JP6023417B2 - Radioactive contaminated soil removal method and vacuum suction device system used therefor - Google Patents

Radioactive contaminated soil removal method and vacuum suction device system used therefor Download PDF

Info

Publication number
JP6023417B2
JP6023417B2 JP2011241600A JP2011241600A JP6023417B2 JP 6023417 B2 JP6023417 B2 JP 6023417B2 JP 2011241600 A JP2011241600 A JP 2011241600A JP 2011241600 A JP2011241600 A JP 2011241600A JP 6023417 B2 JP6023417 B2 JP 6023417B2
Authority
JP
Japan
Prior art keywords
soil
suction
contaminated soil
vacuum
contaminated
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
JP2011241600A
Other languages
Japanese (ja)
Other versions
JP2013096916A (en
Inventor
山口 修一
修一 山口
一弥 木川田
一弥 木川田
佐藤 博
博 佐藤
毅 有泉
毅 有泉
健太朗 森住
健太朗 森住
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tokyo Electric Power Co Inc
Hazama Ando Corp
Original Assignee
Tokyo Electric Power Co Inc
Hazama Ando Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tokyo Electric Power Co Inc, Hazama Ando Corp filed Critical Tokyo Electric Power Co Inc
Priority to JP2011241600A priority Critical patent/JP6023417B2/en
Publication of JP2013096916A publication Critical patent/JP2013096916A/en
Application granted granted Critical
Publication of JP6023417B2 publication Critical patent/JP6023417B2/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Landscapes

  • Cleaning In General (AREA)

Description

本発明は、放射能汚染土除去方法及びこれに用いる真空吸引装置システムに関する。   The present invention relates to a method for removing radioactive contaminated soil and a vacuum suction device system used therefor.

東日本大地震及びこれに伴う津波により原子力発電所に事故が発生したため、放射性物質が大気に拡散され地表に降下して土壌が放射能で汚染されるという事態が起きた。放射能汚染された地域では、汚染土の除去及びその処分が急がれている。この汚染土の除去では、除去された汚染土が、仮置きや中間貯蔵された後、洗浄等の処理を経て、最終処分されることになり、これには、多大な用地面積と費用が必要になるため、この点にも十分に配慮した適切な方法が採用されることが望まれる。
なお、このような放射能による汚染土の除去方法に関する技術の蓄積がないため、記載すべき先行技術文献情報はない。
As a result of the Great East Japan Earthquake and the accompanying tsunami, an accident occurred at a nuclear power plant, causing radioactive materials to diffuse into the atmosphere and fall to the surface of the earth, contaminating the soil with radioactivity. In radioactively contaminated areas, the removal and disposal of contaminated soil is urgently needed. In the removal of this contaminated soil, the removed contaminated soil is temporarily disposed or intermediately stored and then subjected to final disposal, such as washing, which requires a large land area and cost. Therefore, it is desirable to adopt an appropriate method that fully considers this point.
In addition, there is no prior art document information to be described because there is no accumulation of technology related to such a method for removing contaminated soil by radioactivity.

そこで、ここでは、汚染された地域での除染対策と現状の問題点について検討する。
1.除染対策
そもそも放射性物質が地表に降下し土壌を放射能で汚染するという現象は、放射性物質がセシウム134、137等であった場合、これらの物質が土壌粒子に極めて強く吸着される状態である。つまり、降下した放射性物質は、地表面付近の土壌に吸着され、その後降雨等があった場合でも、ほとんど再溶出することなくその場所にとどまり、下方にはわずかしか移行しない。したがって、セシウム134、137等により汚染された土地の土壌は、表面のわずか2cm程度のみが高濃度に汚染され、それ以深はほとんど汚染されていないのが普通である。
よって、汚染された地域での除染対策としては、汚染土の表面の2cm程度の土のみを除去すればよく、これを超えて5cmも10cmも除去(採取)したのでは、除去後の汚染土の仮置き、中間貯蔵、洗浄等の処理、最終処分の数量を大幅に増やすことになり、極めて不経済になるばかりか、用地の確保が困難になる。
このように汚染されている土地を修復するには、土壌表面のわずか2cm程度の高濃度の汚染土を除去するだけで十分である。なお、ここでいう「2cm」は例示であり、実際には状況により異なるが、1〜3cm程度になると考えられる。ここでは代表的な例として2cmと表記する。
2.現状の問題点
しかしながら、汚染されている土地が、学校の校庭のようにほぼ平らで、ある程度以上の広い面積があり、雑草等が繁茂していない土地であれば、モーターグレーダー等の機械を用いて、表面の2cm程度のみの土を除去することは可能であるが、実際に汚染されている土地にこのような好条件のところは少なく、表面に大きな起伏がある、雑草等が繁茂している、作物や雑草等の根が地中に存在している、表面付近の土壌が硬く固結している、地盤の強度が不足し、接地圧の大きな重機や車両は走行できない等、汚染されている土地の状態はさまざまで、表面の2cm程度の土を効率的に除去することは困難な状況にある。
そこで、かかる状況下では、既存の真空吸引装置を用いて土壌を吸引する方法が適していると考えられる。真空吸引装置によれば、狭い場所、障害物の多い場所、畝のような起伏が多い場所などでも表土の除去に有効である。この種の真空吸引装置としては、業務用大型真空掃除機や、し尿や建設汚泥等の吸引回収に用いられる真空吸引車(いわゆるバキュームカー)などがある。しかしながら、これらの装置はそもそも粉体状や泥状のものを吸引搬送する目的で作られているので、汚染土の表面の2cm程度の土を除去するという用途に使用するには大きな問題がある。以下、これらの問題について述べる。
(1)業務用大型真空掃除機
一般的な業務用大型真空掃除機の主な仕様を以下に示す。
吸込仕事率(W):300
運転音(dB):63
最大風量(m3/min):3.5
最大真空度(kPa):22
ホース径:o38mm
このような業務用大型真空掃除機は、家庭用真空掃除機と同様に、吸引した塵埃を本体のタンクに貯留する形式のため、貯留容量はわずか数Lであり、表土除去に利用するには貯留タンクの大型化等、大幅な改造が必要であるが、このような改造ができたとしても、表土の除去に利用するにはさらに次のような問題がある。
(イ)真空度の不足
今回の用途で吸引対象となるのは土壌である。土壌の場合、全くの砂のみからなるさらさらの土壌の場合は別としても、通常は粘土やシルト成分を含んでおり、これら成分によって土壌はかなり大きな粘着力を持つ。その粘着力の値は通常の土壌では少なくとも0.05kgf/cm2(約5kPa)程度はある。
土壌を吸引すると、一度に多量の土壌を吸引してしまい、土壌が満管状態で吸引ホース内を流れる現象が頻繁に発生する。吸引口の形状等を工夫して、一度に土壌のみを吸引せず空気と共にバラバラの状態で土壌を吸引することができたとしても、吸引ホース(配管)の内部の抵抗の多い箇所等では、バラバラで流れていた土壌が再集結し、満管状態になってしまうことが多い。ここで、吸引ホース(φ3.8cm)内の5cm区間内が満管になった状態を想定すると、土壌とホース内面との接触面積は、
3.8cm×3.14×5cm=59.7cm2
となり、その接触面に働く粘着力の合計は、
59.7cm2×0.05kgf/cm2=2.98kgf
となる。したがって、管延長方向の5cm区間内が満管になった土壌を移動させるためには、2.98kgf以上の力が必要である。
これに対して、上記のような業務用大型真空掃除機の最大真空度は22 kPa(約0.22 kgf/cm2)程度であり、ホース断面積
3.8cm×3.8cm×3.14/4=11.3cm2
に作用する吸引力は
11.3cm2×0.22 kgf/cm2=2.49kgf
にしか過ぎず、わずか5cm区間内を満管になった土壌も吸引できない。
(ロ)吸引ホース(配管)径の不足(風量の不足)
土壌には、いわゆる土の成分(砂、シルト、粘土)の他、木屑、根っこのような植物塊や礫、ガラ等の異物が含まれていることが多い。このような異物を一緒に吸引すると、吸引ホース(配管)のつまりの原因となる。つまりを生じることなく安定的に吸引できる異物の大きさは吸引ホース(配管)径のおよそ1/3までであり、上記のような業務用大型真空掃除機に付属しているφ3.8cmの吸引ホース(配管)では、13mm程度までが安定して吸引できる異物の限界である。
ところが、実際の土壌ではもっと大きな異物が多量に含まれていることが多く、少なくとも25mm程度の大きさの異物が含まれていても安定して吸引することが望まれる。このためには、吸引ホース(配管)径を大きくする必要があるが、単純に吸引ホース(配管)径だけを大きくすると、空気の風速が減少し、搬送能力が低下してしまうという問題がある。以下これについて説明する。
土壌を吸引搬送する場合、土壌が吸引ホース等配管内を満管で流れたのでは上述のように大きな真空度が必要となる。真空度はたとえ完全真空が実現できたとしても1気圧(1013hPa=101.3kPa)が限界であるため、土壌を満管にするのではなく、空気の流れに乗せて空気と一緒に搬送する必要がある(いわゆる「空気輸送」と呼ばれる方法である)。この方法で土壌を上方に搬送する場合(地表面の土壌を回収するには土壌を上方に搬送する必要がある)は、配管内を土壌が落下する速度よりも速い上向流で搬送する必要がある。
空気中を球体粒子が落下する速度は、以下に示すストークスの式で計算できる。
ストークスの式
v = g(ρs−ρ)d2/(18μ)
ここで、
v: 粒子落下速度 cm/s
g: 重力加速度 cm/s2 (g=980 cm/s2)
ρs: 粒子密度 g/cm3 (ρs=2.6g/cm3)
ρ: 空気密度 g/cm3 (ρ=0.001293 g/cm3)
d: 粒子直径 cm
μ: 空気の粘度 g/(cm・s) (μ=0.000181 g/(cm・s))
この式で、d=1mm(0.1cm)径の土粒子の落下速度vを求めると、
v=7820cm/s(78.2m/s)
となる。すなわち、1mm径の土粒子を空気の流れに乗せて上方に搬送するには、空気の風速としては78.2m/s以上が必要ということになる。ただし、これは土粒子が球体である場合の理論値であり、実際には土粒子は球体であるとは限らない上、土粒子には他の土粒子が付着したり土粒子が集まって団粒構造をしている場合が多く、この場合は見かけの粒子密度が2.6g/cm3よりも小さくなるため、これよりも若干小さい風速でも上方搬送は可能である。さらに、配管を鉛直ではなく勾配を持たせて配置することによりさらに若干小さい風速でも上方搬送が可能になる。
ここで、上記業務用大型真空掃除機の最大風量3.5m3/min(58300cm3/s)から、φ3.8cmの吸引配管(断面積は上記の通り11.3cm2)を流れる空気の風速を計算すると、
58300/11.3=5160cm/s(51.6m/s)
となる。この風速は、上記のように、1mm径の単独球形土粒子の鉛直上方搬送は不可能ではあるが、土粒子が球形でないことや団粒化していること、鉛直配管にしないことなどを考慮するとなんとか1mm径程度の土粒子の上方搬送は可能な風速である。
これに対し、異物の通過性をよくするため、風量をそのままで配管径のみを、想定する異物サイズ(25mm)の3倍の75mmにした場合、配管断面積は、
7.5cm×7.5cm×3.14/4=44.2cm2
風速は、
58300/44.2=1320cm/s(13.2m/s)
となり、1mm径土粒子の上方搬送に必要な風速78.2m/sと比べてあまりにも小さく、土壌の搬送そのものが不可能となる。
(ハ)土壌の表層剥離の困難さ
土壌の場合は、(イ)で述べたように含まれている粘土やシルト成分によりかなり大きな粘着力を持つため、図5に示すように、単なる真空掃除機の吸引ノズルを土壌表面に近づけただけでは、表面付近の土壌を粘着力に打ち勝って引き剥がして採取することができない。かといって吸引ノズルを土壌表面に全面密着させると、図6に示すように、吸引ノズルが負圧により土壌表面に吸着し吸引ノズルを動かせなくなる。この状態で無理に吸引ノズルを土壌表面から引き剥がすと、図7、図8に示すように、吸引ノズルに土壌が吸着したまま引き剥がされることが多く、このとき引き剥がされる土壌の厚さは、必ずしも望ましい2cmの厚さにならない。2cmの厚さで引き剥がされるとしても、この方法で順次表土除去を行うのではあまりに作業効率が悪すぎる。
(2)真空吸引車
一般的な真空吸引車の主な仕様を以下に示す。
真空度-0.099MPa (740mmhg)
風量(機種により)18〜100m3/min
上記の真空吸引車を使用した場合、真空度に関してはほぼ完全真空に近い値0.099MPa(99kPa)が得られる。これは、上述した業務用大型真空掃除機の4.5倍の真空度である。また、風量18m3/min(300000cm3/s)の機種を使用し、25mmまでの異物が吸引可能なよう
にφ7.5cmの吸引ホース(配管)を使用した場合、管内風速は、
300000/44.2=6790cm/s(67.9m/s)
と、上述した1mm径の球形土粒子の鉛直上方搬送に必要な理論風速78.2m/sに近い値が得られ、実用的には1mm径程度の土粒子までは充分に吸引搬送が可能である。
しかし、今回考えているような放射能汚染土の表層除去にこのような真空吸引車を使用するには、以下のような問題がある。
(イ)真空度が大きすぎる
表層の2cm程度の土壌のみを吸引する場合には、後述するように吸引ノズルと土壌表面との距離を土壌の状態に合わせて微妙に調整する必要があるが、上記の真空吸引車のように真空度が大きい場合は、吸引ノズルが土壌表面に吸い付こうとする力が大きすぎて微妙な調整ができず、その結果として安定して表層の2cm程度の土壌のみを吸引することができなくなる(吸引ノズルと土壌表面との距離を適当な距離に保とうとしても、吸引力が強すぎて勝手に上記図6のように吸引ノズルが土壌表面に吸着してしまう)。
また、吸引ホースも大きい真空度に耐える硬く頑丈なものを使用する必要があり、吸引ホースの取り扱いが困難である。このことがさらに吸引ノズルと土壌表面との距離の調整を難しくする。
(ロ)車両が大きく、作業が必要な箇所に近づけない
車両が最低でも4tタイプの車両となるので、狭い農道等には入り込めない。
3.結び
以上の問題点をまとめると、次のようになる。
(1)業務用大型真空掃除機のような小さな真空度では、吸引ホース(配管)内のわずかな区間が満管状態になった場合でも吸引不能となってしまう。
(2)真空吸引車のような大きな真空度では、ある程度の区間が満管状態になっても吸引可能とはなるが、吸引力が強すぎて、吸引ノズルと土壌表面との距離を適当な距離に保つことができなくなり、土壌表層の2cm程度の土のみを吸引することが困難になる。
(3)また大きな真空度では、それに応じて、吸引ホースも大きい真空度に耐える硬く頑丈なものを使用する必要があり、吸引ホースの取り扱いが困難となる。このことがさらに吸引ノズルと土壌表面との距離の調整を難しくする。
(4)土壌を吸引する場合、混入する25mm程度の大きさの異物まで安定して吸引できるようにするためにはφ7.5cm程度の管径の吸引ホースを使用する必要があり、その際、管内の風速を「空気輸送」が可能な程度の風速にする必要がある。そのためには、業務用大型真空掃除機では風量が全く不足し、真空吸引車程度の風量が必要である。
(5)真空吸引車は、車両が大きすぎるため、作業が必要な箇所に近づくのが困難である。
以上から、既存の真空吸引装置を、放射能により汚染された表層の2cm程度の土壌のみを吸引するような用途に使用する場合、真空吸引装置の真空度は小さすぎても大きすぎても不適であり、風量はある程度大きなものが必要であるが、大きい風量の装置は本体自体が大きくなり、作業が必要な箇所に近づけて設置することが困難になるため、使用に耐える最小限の風量にして、装置をできるだけ小型にすることが望ましいところ、既存の真空吸引装置を汚染土壌の吸引搬送に用いた例がなく、どの程度の真空度の装置であれば、土壌表面の2cm程度の土壌を吸引できるか、どの程度の風量があれば、実用上問題のない管内空気搬送ができるかは、まったくのところ不明である。
Therefore, here we examine the decontamination measures and current problems in the contaminated areas.
1. Measures for decontamination In the first place, the phenomenon that radioactive substances fall to the surface and contaminate the soil with radioactivity is a state in which these substances are adsorbed very strongly by soil particles when the radioactive substances are cesium 134, 137, etc. . In other words, the radioactive material that has fallen is adsorbed by the soil near the ground surface, and even if there is rainfall or the like thereafter, it stays at that location with little re-elution, and moves slightly downward. Therefore, as for the soil of the land contaminated by cesium 134, 137, etc., only about 2 cm of the surface is usually contaminated with high concentration, and it is normal that the depth is not further contaminated.
Therefore, as a decontamination measure in a contaminated area, it is only necessary to remove only about 2 cm of soil on the surface of the contaminated soil. If 5 cm or 10 cm is removed (collected) beyond this, the contamination after removal is removed. The amount of temporary storage of soil, intermediate storage, washing, and final disposal will be greatly increased, which will be extremely uneconomical and difficult to secure land.
To repair such contaminated land, it is sufficient to remove contaminated soil with a high concentration of only 2 cm on the soil surface. Note that “2 cm” here is an example, and it is considered to be about 1 to 3 cm although it actually varies depending on the situation. Here, 2 cm is described as a typical example.
2. However, if the contaminated land is almost flat like a school yard, has a certain area, and weeds are not prosperous, use a machine such as a motor grader. Although it is possible to remove only 2cm of soil on the surface, there are few such favorable conditions in the actually contaminated land, there are large undulations on the surface, weeds etc. Contaminated, such as the roots of crops and weeds exist in the ground, the soil near the surface is hard and solid, the strength of the ground is insufficient, and heavy machinery and vehicles with large ground pressure cannot run The condition of the land is varied, and it is difficult to efficiently remove the soil of about 2 cm on the surface.
Under such circumstances, it is considered that a method of sucking soil using an existing vacuum suction device is suitable. According to the vacuum suction device, it is effective for removing topsoil in a narrow place, a place with many obstacles, and a place with a lot of ups and downs such as dredging. As this type of vacuum suction device, there are a large vacuum cleaner for business use, a vacuum suction wheel (so-called vacuum car) used for suction recovery of human waste, construction sludge, and the like. However, since these devices are originally made for the purpose of sucking and transporting powdery or mud-like materials, there is a big problem in using them for removing soil of about 2 cm from the surface of contaminated soil. . These problems are described below.
(1) Large commercial vacuum cleaner Main specifications of a general commercial large vacuum cleaner are shown below.
Suction work rate (W): 300
Driving sound (dB): 63
Maximum air volume (m3 / min): 3.5
Maximum vacuum (kPa): 22
Hose diameter: o38mm
Such a large-scale vacuum cleaner for business use is a type that stores the sucked dust in the tank of the main body like the vacuum cleaner for home use, so the storage capacity is only a few liters, and it can be used for removing topsoil Significant modifications, such as an increase in the size of the storage tank, are necessary. However, even if such modifications are made, there are the following problems in using it for removing topsoil.
(B) Insufficient degree of vacuum Soil is the target of suction in this application. In the case of soil, aside from the smooth soil consisting entirely of sand, it usually contains clay and silt components, and these components cause the soil to have a considerable adhesive strength. The value of adhesive strength is at least 0.05 kgf / cm2 (about 5 kPa) in normal soil.
When the soil is sucked, a large amount of soil is sucked at once, and the phenomenon that the soil flows in a full pipe state frequently occurs. Even if the shape of the suction port etc. is devised and the soil can be sucked apart with the air without sucking only the soil at once, in places with high resistance inside the suction hose (pipe), In many cases, the soil that was flowing apart gathers again and becomes full. Here, assuming that the inside of the 5 cm section in the suction hose (φ3.8 cm) is full, the contact area between the soil and the hose inner surface is
3.8cm × 3.14 × 5cm = 59.7cm2
The total adhesive force acting on the contact surface is
59.7cm2 × 0.05kgf / cm2 = 2.98kgf
It becomes. Therefore, a force of 2.98 kgf or more is required to move soil that is full in the 5 cm section in the tube extension direction.
On the other hand, the maximum vacuum of the above-mentioned large-scale vacuum cleaners for business use is about 22 kPa (about 0.22 kgf / cm2), and the cross-sectional area of the hose
3.8cm × 3.8cm × 3.14 / 4 = 11.3cm2
The suction force acting on
11.3cm2 × 0.22 kgf / cm2 = 2.49kgf
However, it is impossible to suck soil that is full in a section of only 5 cm.
(B) Insufficient suction hose (pipe) diameter (insufficient air volume)
In addition to so-called soil components (sand, silt, clay), soil often contains foreign matter such as wood chips, roots of plant mass, gravel, and glass. If such foreign matter is sucked together, it will cause clogging of the suction hose (pipe). In other words, the size of foreign matter that can be stably sucked in without causing a problem is up to about 1/3 of the diameter of the suction hose (pipe), and the suction of φ3.8cm that comes with large commercial vacuum cleaners as described above In the case of a hose (pipe), the limit of foreign matter that can be stably sucked up to about 13 mm.
However, actual soil often contains a large amount of larger foreign matter, and it is desirable to stably suction even foreign matter having a size of at least about 25 mm. For this purpose, it is necessary to increase the diameter of the suction hose (pipe). However, if only the diameter of the suction hose (pipe) is simply increased, there is a problem that the wind speed of the air is reduced and the conveying capacity is lowered. . This will be described below.
When sucking and transporting soil, if the soil flows in a full pipe through a pipe such as a suction hose, a high degree of vacuum is required as described above. Even if a complete vacuum can be achieved, the degree of vacuum is limited to 1 atm (1013 hPa = 101.3 kPa), so it is necessary not to fill the soil with a full pipe but to carry it along with the air flow. There is a method (so-called “pneumatic transport”). When transporting soil upward using this method (to recover soil on the ground surface, it is necessary to transport soil upward), it is necessary to transport the pipe in an upward flow that is faster than the rate at which the soil falls. There is.
The speed at which spherical particles fall in the air can be calculated by the Stokes equation shown below.
Stokes formula
v = g (ρs−ρ) d 2 / (18μ)
here,
v : Particle falling speed cm / s
g: Gravity acceleration cm / s2 (g = 980 cm / s2)
ρs: Particle density g / cm3 (ρs = 2.6g / cm3)
ρ: Air density g / cm3 (ρ = 0.001293 g / cm3)
d: Particle diameter cm
μ: Viscosity of air g / (cm · s) (μ = 0.000181 g / (cm · s))
In this equation, when the falling speed v of soil particles having a diameter of d = 1 mm (0.1 cm) is obtained,
v = 7820cm / s (78.2m / s)
It becomes. In other words, in order to carry 1 mm-diameter soil particles on the air flow and transport it upward, the air velocity of 78.2 m / s or more is required. However, this is the theoretical value when the soil particles are spheres. In reality, the soil particles are not necessarily spheres, and other soil particles are attached to the soil particles or gathered together. In many cases, it has a grain structure. In this case, the apparent particle density is smaller than 2.6 g / cm 3, so that it can be conveyed upward even with a slightly lower wind speed. Further, by arranging the pipes with a gradient rather than a vertical direction, it becomes possible to carry the pipe upward even at a slightly lower wind speed.
Here, from the maximum air flow 3.5m3 / min (58300cm3 / s) of the above-mentioned large-scale vacuum cleaner for business use, the wind speed of the air flowing through the suction pipe of φ3.8cm (the cross-sectional area is 11.3cm2 as described above)
58300 / 11.3 = 5160cm / s (51.6m / s)
It becomes. As mentioned above, this wind speed is not possible to vertically convey single spherical soil particles with a diameter of 1 mm, but considering that the soil particles are not spherical, aggregated, or not vertical piping, etc. It is possible to carry soil particles with a diameter of about 1 mm upward.
On the other hand, in order to improve the passage of foreign matter, if the pipe diameter is only 75mm, which is three times the assumed foreign matter size (25mm), with the air flow unchanged,
7.5cm x 7.5cm x 3.14 / 4 = 44.2cm2
The wind speed is
58300 / 44.2 = 1320cm / s (13.2m / s)
Therefore, it is too small compared with the wind speed of 78.2 m / s required for the upward conveyance of 1 mm diameter soil particles, making it impossible to convey the soil itself.
(C) Difficulty of exfoliation of soil surface In the case of soil, as shown in (a), the clay and silt components contained in the soil have a considerably large adhesive force, so as shown in FIG. Just by bringing the suction nozzle of the machine close to the soil surface, the soil near the surface cannot be collected by overcoming the adhesive force and peeling off. However, if the suction nozzle is brought into close contact with the soil surface as shown in FIG. 6, the suction nozzle is adsorbed on the soil surface by the negative pressure, and the suction nozzle cannot be moved. When the suction nozzle is forcibly peeled off from the soil surface in this state, as shown in FIGS. 7 and 8, the soil is often peeled off while the soil is adsorbed to the suction nozzle. Not necessarily the desired 2cm thickness. Even if it is peeled off at a thickness of 2 cm, it is too inefficient to remove the topsoil sequentially by this method.
(2) Vacuum suction wheel The main specifications of a general vacuum suction wheel are shown below.
Degree of vacuum -0.099MPa (740mmhg)
Air volume (depending on model) 18-100m 3 / min
When the above vacuum suction wheel is used, a value of 0.099 MPa (99 kPa), which is close to a complete vacuum, is obtained with respect to the degree of vacuum. This is 4.5 times the vacuum level of the above-mentioned large commercial vacuum cleaner. Also, when using a model with an air volume of 18m 3 / min (300000cm3 / s) and a suction hose (pipe) of φ7.5cm so that foreign matter up to 25mm can be sucked, the wind speed in the pipe is
300000 / 44.2 = 6790cm / s (67.9m / s)
A value close to the theoretical wind speed of 78.2 m / s necessary for the vertical upward conveyance of the above-mentioned 1 mm diameter spherical soil particles can be obtained, and practically suction particles of about 1 mm diameter can be sufficiently sucked and conveyed. .
However, there are the following problems in using such a vacuum suction wheel for removing the surface layer of radioactively contaminated soil as considered this time.
(B) The degree of vacuum is too large. When suctioning only about 2cm of soil on the surface layer, it is necessary to finely adjust the distance between the suction nozzle and the surface of the soil as described later, When the degree of vacuum is large as in the vacuum suction wheel above, the suction nozzle is too strong to attract the soil surface and fine adjustment cannot be performed. (If the distance between the suction nozzle and the soil surface is kept at an appropriate distance, the suction force is too strong and the suction nozzle adsorbs to the soil surface as shown in FIG. 6 without permission. End up).
Further, it is necessary to use a hard and strong suction hose that can withstand a large degree of vacuum, and it is difficult to handle the suction hose. This further makes it difficult to adjust the distance between the suction nozzle and the soil surface.
(B) The vehicle is large and cannot be brought close to the place where work is required. Since the vehicle is a 4t type vehicle at a minimum, it cannot enter narrow agricultural roads.
3. Conclusion The above problems can be summarized as follows.
(1) With a small degree of vacuum such as a large vacuum cleaner for business use, even if a small section in the suction hose (pipe) is full, suction becomes impossible.
(2) With a large degree of vacuum such as a vacuum suction wheel, suction is possible even if a certain section becomes full, but the suction force is too strong and the distance between the suction nozzle and the soil surface is appropriate. It becomes impossible to keep the distance, and it becomes difficult to suck only about 2 cm of soil on the soil surface.
(3) When the degree of vacuum is high, it is necessary to use a hard and strong suction hose that can withstand the high degree of vacuum, which makes it difficult to handle the suction hose. This further makes it difficult to adjust the distance between the suction nozzle and the soil surface.
(4) When sucking soil, it is necessary to use a suction hose with a tube diameter of about φ7.5cm in order to stably suck in foreign matter of about 25mm in size. It is necessary to set the wind speed in the pipe to such a level that “air transportation” is possible. For that purpose, a large-scale vacuum cleaner for business use has a shortage of air volume, and an air volume equivalent to that of a vacuum suction wheel is required.
(5) Since the vacuum suction wheel is too large, it is difficult to approach a place where work is required.
From the above, when using an existing vacuum suction device for the purpose of sucking only the soil of about 2 cm of the surface layer contaminated by radioactivity, it is unsuitable whether the vacuum degree of the vacuum suction device is too small or too large. However, it is necessary to use a device with a large airflow.However, since the main body of the device with a large airflow becomes large and it is difficult to install it close to the place where work is required, the airflow must be kept to a minimum. It is desirable to make the device as small as possible, but there is no example of using an existing vacuum suction device for sucking and transporting contaminated soil. It is unclear at all whether it is possible to suck or how much air volume can be used to carry the air in the pipe without any practical problems.

そこで、本願発明者らは、鋭意研究の結果、表層の2cm程度の土壌のみを問題なく吸引し、回収搬送することのできる真空圧、風量の真空吸引装置を見出し、これを利用した新たな放射能汚染土除去方法及びこの方法に用いる真空吸引装置システムを提供することを目的とする。   Therefore, as a result of earnest research, the inventors of the present application have found a vacuum suction device with a vacuum pressure and an air volume that can suck and recover and transport only about 2 cm of soil on the surface layer without any problem, and use this to create a new radiation. It is an object of the present invention to provide a method for removing contaminated soil and a vacuum suction device system used in this method.

上記目的を達成するために、本発明は、放射能で汚染された土地の汚染土を除去するための放射能汚染土除去方法であって、汚染土を吸引するための吸引管を真空圧30〜70kPa、前記吸引管内の風速を40m/s以上とする風量の真空吸引装置に、汚染土の細粒分を空気と分別して回収するための細粒分回収用サイクロンを有する細粒分回収用ドラム缶及び汚染土の粗粒分を空気と分別して回収するための粗粒分回収用サイクロンを有する粗粒分回収用ドラム缶を介して接し、前記吸引管の吸引口を前記汚染土の表面に前記吸引口と前記汚染土の表面との間に近接する所定の距離を介して対向配置し、前記吸引口と前記汚染土の表面との間に近接する所定の距離を保ちながら、前記吸引管で前記汚染土の表面を真空圧30〜70kPaの範囲で真空吸引することにより、前記汚染土の表層1〜3cm程度を吸引除去するとともに、前記吸引管内を風速40m/s以上にして、前記吸引管で吸引した汚染土を、空気の流れに乗せて空気とともに搬送する空気輸送により、前記細粒分回収用ドラム缶及び前記粗粒分回収用ドラム缶へ搬送回収する、ことを要旨とする。 In order to achieve the above object, the present invention provides a radioactive contaminated soil removing method for removing contaminated soil from radioactively contaminated land, wherein a suction pipe for sucking contaminated soil is provided with a vacuum pressure of 30. -70 kPa , for fine particle collection having a fine particle collection cyclone for separating and collecting fine particles of contaminated soil from air in a vacuum suction device having an air volume of 40 m / s or more in the suction pipe the coarse fraction of the drums and contaminated soil connect via the coarse fraction collecting drum having a coarse fraction collecting cyclone for collecting the separate air, surface suction port of the suction pipe of the contaminated soil The suction port and the surface of the contaminated soil are arranged to face each other through a predetermined distance, and the suction port is maintained while maintaining a predetermined distance between the suction port and the surface of the contaminated soil. A vacuum pressure of 30 to 70 kP is applied to the surface of the contaminated soil with a tube. By vacuum suction in the range of a, as well as aspirate the approximately surface 1~3cm before Symbol contaminated soil, said suction tube in the above wind 40 m / s, the contaminated soil was sucked by the suction pipe, the air by air transport put the flow conveyed with air, the conveying collected into the fine fraction collecting drum and the coarse fraction collecting drum, summarized in that.

また、本発明は、上記放射能汚染土除去方法に用いる真空吸引装置システムであって、真空圧30〜70kPa、吸引管内の風速を40m/s以上とする風量の真空吸引装置と、前記真空吸引装置に接続され、汚染土の細粒分を空気と分別して回収するための細粒分回収用サイクロンを有する細粒分回収用ドラム缶及び汚染土の粗粒分を空気と分別して回収するための粗粒分回収用サイクロンを有する粗粒分回収用ドラム缶と、前記粗粒分回収用サイクロンに接続されて延ばされ、先端に吸引口を有する汚染土を吸引するための吸引管とを備える、ことを要旨とする。 The present invention is also a vacuum suction device system used in the method for removing radioactively contaminated soil, wherein the vacuum suction device has a vacuum pressure of 30 to 70 kPa and a wind speed of 40 m / s or more in the suction pipe, and the vacuum suction device. A drum for collecting fine particles and having a cyclone for collecting fine particles for separating fine particles of contaminated soil from air and connected to the apparatus, and for collecting fine particles of contaminated soil by separating from air A coarse drum collecting drum can having a coarse particle collecting cyclone, and a suction pipe for sucking contaminated soil that is connected to the coarse particle collecting cyclone and extends and has a suction port at the tip , This is the gist.

本発明の放射能汚染土除去方法及びこれに用いる真空吸引装置システムによれば、汚染土を吸引するための吸引管を真空圧30〜70kPa、吸引管内の風速を40m/s以上とする風量の真空吸引装置に、汚染土の細粒分を空気と分別して回収するための細粒分回収用サイクロンを有する細粒分回収用ドラム缶及び汚染土の粗粒分を空気と分別して回収するための粗粒分回収用サイクロンを有する粗粒分回収用ドラム缶を介して接続し、吸引管の吸引口を汚染土の表面に吸引口と汚染土の表面との間に近接する所定の距離を介して対向配置し、吸引口と汚染土の表面との間に近接する所定の距離を保ちながら、吸引管で汚染土の表面を真空圧30〜70kPaの範囲で真空吸引することにより、汚染土の表層1〜3cm程度を吸引除去するようにしたことで、放射能汚染された地域の土地が、表面に大きな起伏がある、雑草等が繁茂している、作物や雑草等の根が地中に存在している、表面付近の土壌が硬く固結している、地盤の強度が不足し、接地圧の大きな重機や車両は走行できないなど、さまざまな状態であっても、汚染された土地の表層1〜3cm程度の高濃度の汚染土を効率的に除去することができ、放射能汚染された土地を効果的に除染することができる。
また、吸引管内を風速40m/s以上にして、吸引管で吸引した汚染土を、空気の流れに乗せて空気とともに搬送する空気輸送により、細粒分回収用ドラム缶及び粗粒分回収用ドラム缶へ搬送回収するようにしたので、吸引管で吸引された汚染土を細粒分回収用ドラム缶及び粗粒分回収用ドラム缶へ円滑に搬送回収することができ、さらに、汚染土を吸引管内に満管で流すことがなく、その分だけ大きな真空度を不要とすることができる。
According to the radioactive contaminated soil removing method of the present invention and the vacuum suction device system used for the method, the suction pipe for sucking the contaminated soil has a vacuum pressure of 30 to 70 kPa, and the wind speed in the suction pipe is 40 m / s or more. In a vacuum suction device, a fine particle collection drum can with a fine particle collection cyclone for separating and collecting fine particles of contaminated soil and air, and for collecting coarse particles of contaminated soil by separating them from air Connected via a coarse particle recovery drum can with a coarse particle recovery cyclone, and the suction port of the suction pipe to the surface of the contaminated soil through a predetermined distance between the suction port and the surface of the contaminated soil The surface layer of the contaminated soil is disposed by facing the surface of the contaminated soil in a vacuum pressure range of 30 to 70 kPa with a suction pipe while maintaining a predetermined distance between the suction port and the surface of the contaminated soil. removed by suction about 1~3cm By was Unishi, radioactive contaminated area of land, there is a large undulating on the surface, weeds and the like are to flourish, the roots of such crops and weeds are present in the ground, the soil in the vicinity of the surface is are hard consolidation, the strength of the ground is insufficient, such as the inability to large heavy equipment and vehicles traveling ground pressure, even different state, contamination of the high concentration of about surface 1~3cm of contaminated sites The soil can be removed efficiently, and the radioactively contaminated land can be effectively decontaminated.
Also, the inside of suction引管wind speed 40 m / s or more over, the sucked contaminated soil in the suction tube, placed on a flow of air by the air transport for transporting with air, the fine fraction collecting drum and coarse fraction recovered since to convey recovered to use drums, the sucked contaminated soil in the suction tube can be smoothly conveyed collected into the fine fraction collecting drum and the coarse fraction collecting drum, further, the polluted soil suction pipe Therefore, a large degree of vacuum can be eliminated.

本発明の一実施の形態における放射能汚染土除去方法に用いる真空吸引装置システムの構成を示す図The figure which shows the structure of the vacuum suction apparatus system used for the radioactive contamination soil removal method in one embodiment of this invention. 同方法及びシステムによる作用(吸引ノズルと土壌表面との距離を適正に保った場合の表面の土壌の吸引状況)を示す図The figure which shows the effect | action (the suction condition of the surface soil when the distance of a suction nozzle and the soil surface is kept appropriate) by the method and system 同方法及びシステムによる作用(吸引ノズルを順次移動させて次々と表面の土壌を吸引している状況)を示す図The figure which shows the effect | action (the situation where the suction nozzle is moved sequentially and the surface soil is sucked one after another) by the method and system 同方法及びシステムによる作用(吸引後の土壌の状況)を示す図The figure which shows the action (the situation of the soil after the suction) by the method and system 既存の真空吸引装置を用いた土壌表面の吸引作用(吸引ノズルを土壌表面に近づけても、土壌表面に浮いている土粒子しか吸引できない状態)を示す図The figure which shows the suction action of the soil surface using the existing vacuum suction device (the state where only the soil particles floating on the soil surface can be sucked even if the suction nozzle is brought close to the soil surface) 同真空吸引装置を用いた土壌表面の吸引作用(吸引ノズルを土壌表面に全面密着させて、吸引ノズルが土壌表面に吸着して動かせない状態)を示す図The figure which shows the suction action of the soil surface using the same vacuum suction device (a state where the suction nozzle is brought into close contact with the soil surface and the suction nozzle cannot be adsorbed and moved on the soil surface) 同真空吸引装置を用いた土壌表面の吸引作用(吸引ノズルが土壌表面に吸着された状態から吸引ノズルを無理に引き剥がそうとしている状態)を示す図The figure which shows the suction action of the soil surface using the same vacuum suction device (the state where the suction nozzle is forcibly removed from the state where the suction nozzle is adsorbed on the soil surface) 同真空吸引装置を用いた土壌表面の吸引作用(土壌表面に吸着された吸引ノズルを無理に引き剥がした結果、厚さ不定の土壌が吸引ノズルに吸着されたまま引き剥がされた状態)を示す図Shows the suction action of the soil surface using the same vacuum suction device (as a result of forcibly peeling off the suction nozzle adsorbed on the soil surface, the soil of indeterminate thickness being peeled off while being adsorbed by the suction nozzle) Figure

以下、この発明を実施するための形態について図を用いて説明する。
この放射能汚染土除去方法は、放射能で汚染された土地の汚染土を除去するためのもので、この方法では、特に、真空圧30〜70kPaの真空吸引装置を用い、この真空吸引装置に汚染土回収容器を介して吸引管を接続し、この吸引管の吸引口を汚染濃度の高い土壌の表面に近接して対向配置して、土壌の表層を真空圧30〜70kPaの範囲で吸引除去する、ものとした。
この場合、真空吸引装置に吸引管内の風速を40m/s以上とする風量の真空吸引装置を用いることが好ましく、吸引管内を風速40m/s以上にして、吸引管で吸引した汚染土を汚染土回収容器へ搬送回収することが望ましい。
Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
This radioactive contamination soil removal method is for removing contaminated soil from radioactively contaminated land. In this method, in particular, a vacuum suction device with a vacuum pressure of 30 to 70 kPa is used, and this vacuum suction device is used. A suction pipe is connected via a contaminated soil collection container, and the suction port of this suction pipe is placed close to the surface of the soil with a high contamination concentration, and the surface of the soil is removed by suction within a vacuum pressure range of 30 to 70 kPa. I was supposed to.
In this case, it is preferable to use a vacuum suction device having an air volume of 40 m / s or more in the suction pipe as the vacuum suction device, and the contaminated soil sucked by the suction pipe with the wind speed of 40 m / s or more in the suction pipe is used as the contaminated soil. It is desirable to transport and collect it in a collection container.

図1にこの放射能汚染土除去方法に用いる真空吸引装置システムを示している。このシステムは、汚染土を吸引するための吸引管1と、吸引管1にサイクロン2を介して接続され、汚染土を回収するための汚染土回収容器3と、汚染土回収容器3に接続される、真空圧30〜70kPa、吸引管1内の風速を40m/s以上とする風量の真空吸引装置本体4とを備えて構成される。
この場合、吸引管1に吸引ホース11、12、13を用い、吸引ホース11の先端に吸引口として吸引ノズル10が連結される。汚染土回収容器3は、汚染土の粗粒分を空気と分別して回収するための粗粒分回収用サイクロン21を一体に有する粗粒分回収用ドラム缶31と、汚染土の細粒分を空気と分別して回収するための細粒分回収用サイクロン22を一体に有する細粒分回収用ドラム缶32とを備え、粗粒分回収用サイクロン21に吸引ノズル10から延びる吸引ホース11が接続され、粗粒分回収用サイクロン21と細粒分回収用サイクロン22との間に吸引ホース12が接続される。真空吸引装置本体4は、既述のとおり、真空圧30〜70kPa、吸引管内の風速を40m/s以上とする風量の真空吸引装置が採用される。この真空吸引装置本体4と細粒分回収用サイクロン22との間に吸引ホース13が接続される。
このようにして吸引ノズル10を汚染濃度の高い土壌の表面に近接して対向配置し、土壌の表層を真空圧30〜70kPaの範囲で吸引除去し、吸引ノズル10で吸引した汚染土を風速を40m/s以上の吸引ホース11、12内を通して各回収用ドラム缶31、32へ搬送回収するようになっている。
FIG. 1 shows a vacuum suction device system used in this radioactively contaminated soil removing method. This system is connected to a suction pipe 1 for sucking contaminated soil, a suction pipe 1 via a cyclone 2 and connected to a contaminated soil recovery container 3 for collecting the contaminated soil, and a contaminated soil recovery container 3. A vacuum suction device body 4 having a vacuum pressure of 30 to 70 kPa and an air volume of 40 m / s or higher in the suction pipe 1.
In this case, suction hoses 11, 12, and 13 are used in the suction pipe 1, and the suction nozzle 10 is connected to the tip of the suction hose 11 as a suction port. The contaminated soil collection container 3 includes a coarse particle collection drum 31 integrally having a coarse particle collection cyclone 21 for separating and collecting coarse particles of contaminated soil from air, and fine particles of contaminated soil. And a fine particle collection drum 32 having a fine particle collection cyclone 22 for separation and collection, and a suction hose 11 extending from the suction nozzle 10 is connected to the coarse particle collection cyclone 21, A suction hose 12 is connected between the granule collection cyclone 21 and the fine particle collection cyclone 22. As described above, the vacuum suction device body 4 employs a vacuum suction device having a vacuum pressure of 30 to 70 kPa and an air volume of 40 m / s or higher in the suction pipe. A suction hose 13 is connected between the vacuum suction device main body 4 and the fine particle collecting cyclone 22.
In this way, the suction nozzle 10 is placed close to the surface of the soil having a high contamination concentration, and the surface layer of the soil is sucked and removed in a vacuum pressure range of 30 to 70 kPa, and the wind speed of the contaminated soil sucked by the suction nozzle 10 is increased. It is transported and collected to the respective recovery drums 31 and 32 through the suction hoses 11 and 12 of 40 m / s or more.

本願出願人は、この真空吸引装置システムを真空圧47.1kPa、風量12.1m3/minの真空吸引装置(外形寸法・重量:1,930×800×H1,230mm,650kg)、ホース径φ7.5cmの吸引ホースにより具体化し、このシステムを使用して、土壌の表層を吸引する実験を行った。
実験の結果、吸引ノズルの形状等は土壌の種類や状態により適、不適はあるものの、どのような形状のノズルを使った場合でも、真空吸引装置本体の真空圧47.1kPaという弱すぎず強すぎない吸引力により、吸引ノズルと土壌表面との距離を適正に保つことができた。この距離を適正に保つことができたことは、真空圧がそれほど大きくないために比較的軽量でフレキシビリティに富む吸引ホースを使用できたことも寄与している。このように吸引ノズルと土壌表面との距離を適正に保つことができた結果、土壌表面に浮いている土粒子のみでなく、土壌の表面を数mm以上の厚さで粘着力に打ち勝って吸引することができた。一回の吸引で所定の2cmの厚さに吸引できない場合には同じ場所を数回吸引することにより2cmの厚さの吸引が可能であった。
図2に吸引ノズル10と土壌表面との距離を適正に保った場合の表面の土壌の吸引状況を示す。このような状態では、図示したように表面付近の土壌を粘着力に打ち勝って引き剥がし、吸引することができる。図3に上記の状態で吸引ノズル10を順次移動させて次々と表面の土壌を吸引している状況を示し、図4に吸引後の土壌の状況を示す。
また、47.1kPa(0.481kgf/cm2)の真空圧で吸引したことにより、径φ7.5cmの吸引ホース11(断面積44.2cm2)の断面積に働く総吸引力は、0.481×44.2=21.3kgfとなった。径φ7.5cmの吸引ホース11の周長は23.6cm2であるため、土壌の粘着力を0.05kgf/cm2とすると、満管になった場合の土壌の総粘着力は、ホース延長方向15cmあたりで17.7 kgfである。よって、吸引ホース内の15cm程度が満管になっても真空圧で吸引可能となったことになる。実際に吸引したところ、一度に多量の土壌を吸引しないように注意していれば、たまに吸引ホース内を土壌が満管で流れることはあっても、吸引不能になることは頻繁には生じず、実用上は問題なく連続吸引することができた。
また、12.1m3/min(202000cm3/s)の風量で吸引したため、径φ7.5cmの吸引ホース(断面積44.2cm2)内の風速は、202000/44.2=4570cm/s(45.7m/s)となった。この値は、上述した1mm径球形土粒子の上方搬送に必要な理論風速78.2m/sよりは小さめの値であるが、前述したような理由により実際には1mm以上の径の土粒子も十分にドラム缶内に搬送、回収できた。
以上により、真空圧47.1kPa、風量12.1m3/minの真空吸引装置を用いた真空吸引装置システムで、表層の2cm程度の土壌のみを問題なく吸引できることが確認された。
このようにこのシステムにより表層2cm程度の汚染土の除去回収が実用的に可能であることが判明したことで、実際にセシウムで放射能汚染されている土地において表層土の除去による除染効果を確認した。この場合、除去前の表土1〜2mmをスコップで剥ぎ取り、この土壌の放射能をゲルマニウム半導体分析器で測定して、処理前の土壌の放射能濃度とし、また、上記システムで2cm程度表層を除去した後の新しい土壌表面の土1〜2mmをスコップで剥ぎ取り、同様に放射能分析して処理後の土壌の放射能濃度とした。その結果を表1に示す。

Figure 0006023417
この表1に示す通り、処理前には882Bq/kgの濃度であったものが、吸引処理後は測定限界(39 Bq/kg)以下の濃度となり、十分な効果が確認できた。 The applicant of the present application uses this vacuum suction device system as a vacuum suction device with vacuum pressure of 47.1 kPa and air volume of 12.1 m 3 / min (external dimensions and weight: 1,930 × 800 × H1,230 mm, 650 kg), suction with hose diameter φ7.5 cm The experiment was carried out by suctioning the surface of the soil using the system, which was embodied by a hose.
As a result of the experiment, although the shape of the suction nozzle is suitable or unsuitable depending on the type and condition of the soil, the vacuum pressure of the vacuum suction device body is not too weak and too strong, regardless of the shape of the nozzle used. With no suction force, the distance between the suction nozzle and the soil surface could be kept properly. The fact that this distance can be maintained properly also contributes to the fact that a vacuum hose is not so large that a suction hose that is relatively light and flexible can be used. As a result of maintaining the distance between the suction nozzle and the soil surface in this way, not only the soil particles floating on the soil surface but also the surface of the soil is overcome by overcoming the adhesive force with a thickness of several millimeters or more. We were able to. When suctioning to a predetermined thickness of 2 cm was not possible with a single suction, suction of a thickness of 2 cm was possible by sucking the same place several times.
FIG. 2 shows the soil suction state on the surface when the distance between the suction nozzle 10 and the soil surface is properly maintained. In such a state, as shown in the figure, the soil in the vicinity of the surface can be removed by overcoming the adhesive force and sucked. FIG. 3 shows a state where the suction nozzle 10 is sequentially moved in the above state to suck the soil on the surface one after another, and FIG. 4 shows the state of the soil after the suction.
In addition, the total suction force acting on the cross-sectional area of the suction hose 11 (cross-sectional area 44.2 cm2) with a diameter of φ7.5 cm is 0.481 × 44.2 = 21.3 kgf by suctioning at a vacuum pressure of 47.1 kPa (0.481 kgf / cm2). became. Since the circumference of the suction hose 11 with a diameter of 7.5 cm is 23.6 cm 2, if the soil adhesive strength is 0.05 kgf / cm 2, the total soil adhesive strength when the pipe is full is about 15 cm in the hose extension direction. 17.7 kgf. Therefore, even if about 15 cm in the suction hose becomes full, it can be sucked with vacuum pressure. In fact, if care is taken not to suck a large amount of soil at the same time, even if soil sometimes flows through the suction hose as a full pipe, it will not frequently become impossible to suck. In practical use, continuous suction was possible.
In addition, because suction was performed at an air flow of 12.1 m 3 / min (202000 cm 3 / s), the air speed in the suction hose (cross-sectional area of 44.2 cm 2) with a diameter of 7.5 cm was 202000 / 44.2 = 4570 cm / s (45.7 m / s) became. This value is smaller than the theoretical wind speed of 78.2 m / s necessary for the upward conveyance of 1 mm diameter spherical soil particles as described above, but in reality, soil particles with a diameter of 1 mm or more are also sufficient for the reasons described above. It was able to be transported and collected in the drum.
Based on the above, it was confirmed that the vacuum suction device system using the vacuum suction device with a vacuum pressure of 47.1 kPa and an air volume of 12.1 m 3 / min can suck only soil of about 2 cm on the surface without any problem.
In this way, it was found that this system can practically remove and collect contaminated soil with a surface layer of about 2 cm, and the decontamination effect of surface soil removal on land that is actually radioactively contaminated with cesium. confirmed. In this case, remove 1 to 2 mm of the topsoil before removal with a scoop, measure the radioactivity of this soil with a germanium semiconductor analyzer to obtain the radioactivity concentration of the soil before treatment, and the surface layer of about 2 cm with the above system 1-2 mm of soil on the surface of the new soil after removal was peeled off with a scoop, and the radioactivity analysis was performed in the same manner to obtain the radioactive concentration of the soil after treatment. The results are shown in Table 1.
Figure 0006023417
As shown in Table 1, the concentration before the treatment was 882 Bq / kg, but after the suction treatment, the concentration was below the measurement limit (39 Bq / kg), and a sufficient effect could be confirmed.

また、この真空吸引装置の実験は仕様を変えて引き続き行った。次の実験では、真空圧53.9kPa、風量17.4m3/min(外形寸法・重量:2,600×1,200×H1,325mm,1,450kg)の真空吸引装置を用いて、表層土壌の吸引実験を行った。この場合、この真空吸引装置の標準ホース径が125mmであるところ、上記真空圧47.1kPaの真空吸引装置の標準ホース(ホース径75mm)をそのまま使用し、ホース内の風速を65.6m/sに高めた。
その結果、この装置でも効率的に表層土壌の吸引ができることを確認した。この場合、ホース内の風速が高まったため、より効率的に表土の除去が可能になった。
Moreover, the experiment of this vacuum suction device was continued by changing specifications. In the next experiment, a surface soil suction experiment was conducted using a vacuum suction device with a vacuum pressure of 53.9 kPa and an air volume of 17.4 m 3 / min (external dimensions and weight: 2,600 × 1,200 × H1,325 mm, 1,450 kg). In this case, when the standard hose diameter of this vacuum suction device is 125 mm, the standard hose of the vacuum suction device with the vacuum pressure of 47.1 kPa (hose diameter 75 mm) is used as it is, and the wind speed in the hose is increased to 65.6 m / s. It was.
As a result, it was confirmed that the surface soil can be efficiently sucked with this apparatus. In this case, since the wind speed in the hose increased, the topsoil could be removed more efficiently.

このような実験から、真空圧30〜70kPa、吸引管内の風速を40m/s以上とする風量の真空吸引装置であれば、同様の結果が得られることが分かった。   From such an experiment, it was found that the same result could be obtained with a vacuum suction device having a vacuum pressure of 30 to 70 kPa and a wind speed of 40 m / s or more in the suction pipe.

以上のことから明らかなように、この放射能汚染土除去方法及びこれに用いる真空吸引装置システムでは、真空圧30〜70kPaの真空吸引装置を用い、吸引管の吸引口を汚染濃度の高い土壌の表面に近接して対向配置し、土壌の表層を真空圧30〜70kPaの範囲で吸引除去するようにしたので、放射能汚染された地域の土地が、例えば表面に大きな起伏がある、雑草等が繁茂している、作物や雑草等の根が地中に存在している、表面付近の土壌が硬く固結している、地盤の強度が不足し、接地圧の大きな重機や車両は走行できない等、さまざまな状態であっても、土壌表面の2cm程度の土を効率的に除去することができ、放射能汚染された土地を効果的に除染することができる。
また、この場合、吸引管内を風速40m/s以上にして、吸引管で吸引した汚染土を汚染土回収容器へ搬送回収するようにしたので、吸引管で吸引された汚染土を、空気の流れに乗せて空気と一緒に搬送する空気輸送により、汚染土回収容器へ円滑に搬送回収することができる。したがって、汚染土を吸引管内に満管で流すことがなく、その分だけ大きな真空度を不要とすることができる。
As is apparent from the above, in this radioactively contaminated soil removal method and the vacuum suction device system used therefor, a vacuum suction device with a vacuum pressure of 30 to 70 kPa is used, and the suction port of the suction tube is used for soil with a high contamination concentration. Since the surface of the soil is removed in a vacuum pressure range of 30 to 70 kPa in close proximity to the surface, the land in the radioactively contaminated area has large undulations on the surface, such as weeds. Overgrown, roots of crops and weeds exist in the ground, soil near the surface is hard and solid, ground strength is insufficient, heavy equipment and vehicles with large ground pressure cannot run, etc. Even in various states, the soil of about 2 cm on the soil surface can be efficiently removed, and the radioactively contaminated land can be effectively decontaminated.
Further, in this case, the inside of the suction pipe is set to a wind speed of 40 m / s or more, and the contaminated soil sucked by the suction pipe is transported and recovered to the contaminated soil collection container. By pneumatic transportation that is carried together with air, it can be smoothly conveyed and collected into the contaminated soil collection container. Therefore, the contaminated soil does not flow into the suction pipe as a full pipe, and a large degree of vacuum can be eliminated.

1 吸引管
10 吸引ノズル
11 吸引ホース
12 吸引ホース
13 吸引ホース
2 サイクロン
21 粗粒分回収用サイクロン
22 細粒分回収用サイクロン
3 汚染土回収容器
31 粗粒分回収用ドラム缶
23 細粒分回収用ドラム缶
4 真空吸引装置本体
DESCRIPTION OF SYMBOLS 1 Suction pipe 10 Suction nozzle 11 Suction hose 12 Suction hose 13 Suction hose 2 Cyclone 21 Cyclone for coarse particle collection 22 Cyclone for fine particle collection 3 Contaminated soil collection container 31 Drum can for coarse particle collection 23 Drum can for fine particle collection 4 Vacuum suction device

Claims (2)

放射能で汚染された土地の汚染土を除去するための放射能汚染土除去方法であって、
汚染土を吸引するための吸引管を真空圧30〜70kPa、前記吸引管内の風速を40m/s以上とする風量の真空吸引装置に、汚染土の細粒分を空気と分別して回収するための細粒分回収用サイクロンを有する細粒分回収用ドラム缶及び汚染土の粗粒分を空気と分別して回収するための粗粒分回収用サイクロンを有する粗粒分回収用ドラム缶を介して接し、
前記吸引管の吸引口を前記汚染土の表面に前記吸引口と前記汚染土の表面との間に近接する所定の距離を介して対向配置し、前記吸引口と前記汚染土の表面との間に近接する所定の距離を保ちながら、前記吸引管で前記汚染土の表面を真空圧30〜70kPaの範囲で真空吸引することにより、前記汚染土の表層1〜3cm程度を吸引除去するとともに、前記吸引管内を風速40m/s以上にして、前記吸引管で吸引した汚染土を、空気の流れに乗せて空気とともに搬送する空気輸送により、前記細粒分回収用ドラム缶及び前記粗粒分回収用ドラム缶へ搬送回収する
ことを特徴とする放射能汚染土除去方法。
A radioactive soil removal method for removing contaminated soil from radioactively contaminated land,
A vacuum suction device for sucking the contaminated soil has a vacuum pressure of 30 to 70 kPa and a wind speed in the suction tube of 40 m / s or more to separate and collect fine particles of the contaminated soil from air. the coarse fraction of the fine fraction collecting drums and contaminated soil having a fine fraction collecting cyclone through the coarse fraction collecting drum having a coarse fraction collecting cyclone for collecting the separate air connections teeth ,
The suction port of the suction pipe is disposed opposite to the surface of the contaminated soil through a predetermined distance close to the surface between the suction port and the surface of the contaminated soil, and between the suction port and the surface of the contaminated soil. while maintaining a predetermined distance in proximity to, by vacuum suction the surface of the contaminated soil in a range of vacuum pressures 30~70kPa in the suction tube, the degree of surface 1~3cm sucks removed before Symbol polluted soil, The fine particle collection drum can and the coarse particle collection material are collected by air transportation in which the inside of the suction tube is set to a wind speed of 40 m / s or more and the contaminated soil sucked by the suction tube is carried on the air flow along with the air. Transport and collect to drums ,
A method for removing radioactively contaminated soil.
真空圧30〜70kPa、吸引管内の風速を40m/s以上とする風量の真空吸引装置と、前記真空吸引装置に接続され、汚染土の細粒分を空気と分別して回収するための細粒分回収用サイクロンを有する細粒分回収用ドラム缶及び汚染土の粗粒分を空気と分別して回収するための粗粒分回収用サイクロンを有する粗粒分回収用ドラム缶と、前記粗粒分回収用サイクロンに接続されて延ばされ、先端に吸引口を有する汚染土を吸引するための吸引管とを備える、請求項1に記載の放射能汚染土除去方法に用いる真空吸引装置システム A vacuum suction device having a vacuum pressure of 30 to 70 kPa and an air flow rate of 40 m / s or more in the suction pipe, and a fine particle fraction that is connected to the vacuum suction device and separates and collects fine particles of contaminated soil. A fine particle recovery drum can having a recovery cyclone, a coarse particle recovery drum can having a coarse particle recovery cyclone for separating and recovering coarse particles of contaminated soil from the air, and the coarse particle recovery cyclone A vacuum suction device system for use in the radioactive contaminated soil removing method according to claim 1, further comprising a suction pipe for sucking contaminated soil having a suction port at a distal end and connected to the pipe .
JP2011241600A 2011-11-02 2011-11-02 Radioactive contaminated soil removal method and vacuum suction device system used therefor Active JP6023417B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2011241600A JP6023417B2 (en) 2011-11-02 2011-11-02 Radioactive contaminated soil removal method and vacuum suction device system used therefor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2011241600A JP6023417B2 (en) 2011-11-02 2011-11-02 Radioactive contaminated soil removal method and vacuum suction device system used therefor

Publications (2)

Publication Number Publication Date
JP2013096916A JP2013096916A (en) 2013-05-20
JP6023417B2 true JP6023417B2 (en) 2016-11-09

Family

ID=48618981

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2011241600A Active JP6023417B2 (en) 2011-11-02 2011-11-02 Radioactive contaminated soil removal method and vacuum suction device system used therefor

Country Status (1)

Country Link
JP (1) JP6023417B2 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015175778A (en) * 2014-03-17 2015-10-05 清水建設株式会社 Removal/collection system of contaminant

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59194805A (en) * 1983-04-18 1984-11-05 工業技術院長 Method and device for cutting concrete material by laser
JP2005155198A (en) * 2003-11-26 2005-06-16 Kobe Steel Ltd Earth and sand remover and method for unearthing buried substance making use thereof

Also Published As

Publication number Publication date
JP2013096916A (en) 2013-05-20

Similar Documents

Publication Publication Date Title
US9770741B1 (en) Pipe cleaning apparatus
JP5260720B2 (en) Resource recovery device and method for collecting resources from soil
CN205851548U (en) A kind of mechanical ventilation system for repairing volatility organic polluted soil
CN106694534A (en) Organic bank-soil leaching system for repairing heavy metal and petroleum soil contamination
CN105750270A (en) System for removing and recovering loose sand in working box of 3D (three-dimensional) printing equipment
CN105625494A (en) Deepwater negative-pressure desilting system
US20150266068A1 (en) Method and system to excavate and remove underground noxious vapors
JP6023417B2 (en) Radioactive contaminated soil removal method and vacuum suction device system used therefor
JP2006181529A (en) Dust removal apparatus
JP5278885B1 (en) Method and apparatus for removing contaminants contained in agricultural soil
KR101350968B1 (en) Vehicle typed apparatus for remedying asbestos contaminated soil
JP2007050071A (en) Powder granule recovery method and powder granule recovery apparatus
JP2014125754A (en) Apparatus and method for recovering sludge
US5589073A (en) System and method for removing asbestos and other solid particles from a slurry
JP3132402U (en) Forest surface soil sampling device
CN206444996U (en) Double pump multiphase extraction device applied to soil and groundwater remediation
CN108565036A (en) Equipment and sweep-out method are quickly removed in a kind of hard dielectric surface radioactive contamination
RU2613751C1 (en) Off-road vehicle
JP6740772B2 (en) Dewatering floor
CN217596841U (en) Recovery system for sand blasting processing
JP6971523B2 (en) Decontamination method and decontamination system
JP2837602B2 (en) Sediment transport system for shield method
CN216741614U (en) Tunnel sludge treatment device for mining engineering
CN218508535U (en) Ditch silt processing apparatus for hydraulic engineering
CN212831154U (en) Cement promotes conveying equipment for cement manufacture

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20140901

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20150715

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20150721

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20150909

A02 Decision of refusal

Free format text: JAPANESE INTERMEDIATE CODE: A02

Effective date: 20160308

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20160519

A911 Transfer to examiner for re-examination before appeal (zenchi)

Free format text: JAPANESE INTERMEDIATE CODE: A911

Effective date: 20160713

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20160907

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20161007

R150 Certificate of patent or registration of utility model

Ref document number: 6023417

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

S531 Written request for registration of change of domicile

Free format text: JAPANESE INTERMEDIATE CODE: R313531

R350 Written notification of registration of transfer

Free format text: JAPANESE INTERMEDIATE CODE: R350

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250