JPH06222178A - Reactivity controller - Google Patents

Reactivity controller

Info

Publication number
JPH06222178A
JPH06222178A JP50A JP3114193A JPH06222178A JP H06222178 A JPH06222178 A JP H06222178A JP 50 A JP50 A JP 50A JP 3114193 A JP3114193 A JP 3114193A JP H06222178 A JPH06222178 A JP H06222178A
Authority
JP
Japan
Prior art keywords
thermal expansion
reactivity
core
wire
absorber
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.)
Withdrawn
Application number
JP50A
Other languages
Japanese (ja)
Inventor
Kazumi Ikeda
一三 池田
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.)
Mitsubishi Heavy Industries Ltd
Original Assignee
Mitsubishi Atomic Power Industries Inc
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 Mitsubishi Atomic Power Industries Inc filed Critical Mitsubishi Atomic Power Industries Inc
Priority to JP50A priority Critical patent/JPH06222178A/en
Publication of JPH06222178A publication Critical patent/JPH06222178A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00Energy generation of nuclear origin
    • Y02E30/30Nuclear fission reactors

Landscapes

  • Structure Of Emergency Protection For Nuclear Reactors (AREA)
  • Monitoring And Testing Of Nuclear Reactors (AREA)

Abstract

PURPOSE:To provide a reactivity controller which provides greater negative reactivity, with a coolant temperature rise effected by use of thermal expansion difference. CONSTITUTION:A reactivity controller has a hexagonal outer shape with a lower inlet nozzle 4, a wrapper tube 2 and a handling head 1 and contains fuel elements 3 and a reactivity control portion 8 therein. The wrapper tube 2 separates other core constituents from a coolant passage and maintains structural strength. The handling head 1 serves as a coolant outlet and the exposed core of a fuel handling machine. The fuel elements 3 each comprise a pellet containing Pu and U and packed in a clad pipe made of stainless steel. The reactivity control portion 8 comprises a coaxial cable and an absorber 7 attached to the end of wire 6 and containing a material that absorbs neutrons of boron or the like well, the coaxial cable consisting of wire 6 with great coefficient of thermal expansion and an outer tube 11 with small coefficient of thermal expansion, and wound to a shaft 5 with small coefficient of thermal expansion. During rated operation, the absorber 7 is located near the upper end of the core.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【産業上の利用分野】本発明は、主としてナトリウム冷
却型高速増殖炉の反応度制御装置に関するものである。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a reactivity control device for a sodium cooled fast breeder reactor.

【0002】[0002]

【従来の技術】従来の原子炉システムにおける反応度制
御装置は、主に制御棒駆動機構に関するものである。従
来の制御棒駆動機構13は、図4に示すように、原子炉
容器15の上部に取り付けられ、動力により、炉心11
に吸収体12の挿入・引抜きを行うことにより、炉心1
1の反応度を制御するように設計されている。
2. Description of the Related Art A reactivity control device in a conventional reactor system mainly relates to a control rod drive mechanism. As shown in FIG. 4, the conventional control rod drive mechanism 13 is attached to the upper portion of the reactor vessel 15 and is driven by power to drive the reactor core 11.
By inserting and withdrawing the absorber 12 into and from the core 1
It is designed to control the reactivity of 1.

【0003】制御棒駆動軸は、炉心11で、昇温された
冷却材に接しているため、その熱膨張により、吸収体1
2が炉心に挿入される。これを制御棒駆動軸の熱膨張効
果と言う。
Since the control rod drive shaft is in contact with the heated coolant in the core 11, the thermal expansion of the control rod causes the absorber 1 to move.
2 is inserted into the core. This is called the thermal expansion effect of the control rod drive shaft.

【0004】[0004]

【発明が解決しようとする課題】上記のような従来の反
応度制御装置における制御棒駆動軸の熱膨張効果には、
次のような欠点がある。
The thermal expansion effect of the control rod drive shaft in the conventional reactivity control device as described above is as follows.
It has the following drawbacks.

【0005】 制御棒駆動軸の熱膨張による伸びが小
さい。
Elongation due to thermal expansion of the control rod drive shaft is small.

【0006】たとえば、駆動軸の長さを6m、駆動軸の
材料がステンレス(SUS)でSUSの熱膨張率を1.
7×10-5/℃とすると、冷却材温度が100℃上昇し
た場合、制御棒の軸の伸びは約1cmである。この伸び
は、制御棒を通常動かす距離、たとえば1mにくらべ、
きわめてわずかである。
For example, the length of the drive shaft is 6 m, the material of the drive shaft is stainless steel (SUS), and the coefficient of thermal expansion of SUS is 1.
At 7 × 10 −5 / ° C., when the coolant temperature rises by 100 ° C., the elongation of the control rod shaft is about 1 cm. This elongation is compared to the distance that the control rod normally moves, for example, 1 m,
Very few.

【0007】 制御棒挿入状態により効果が大きく変
化する。
The effect greatly changes depending on the control rod insertion state.

【0008】図5に示す制御棒吸収体の位置とその効果
との関係からわかるように、制御棒駆動軸の熱膨張効果
は大きく変化する。原子炉の運転期間の末期に、制御棒
吸収体の下端は、炉心上端の近傍にあり、その効果は、
極めて、わずかになる。
As can be seen from the relationship between the position of the control rod absorber and its effect shown in FIG. 5, the thermal expansion effect of the control rod drive shaft changes greatly. At the end of the operating period of the reactor, the lower end of the control rod absorber is near the upper end of the core and its effect is
Extremely small.

【0009】たとえば、前述の想定での設計例では−2
×10-6Δk/k/℃程度である。
For example, in the design example based on the above assumption, -2
It is about × 10 -6 Δk / k / ° C.

【0010】 原子炉容器の熱膨張で相殺される。This is offset by the thermal expansion of the reactor vessel.

【0011】冷却材温度が長時間高温のままであった場
合、一度、駆動軸の熱膨張により、炉心に挿入された制
御棒は、その後徐々に温度上昇した原子炉容器の熱膨張
により、引抜れる。
When the coolant temperature remains high for a long time, the control rod inserted into the core is once pulled out due to the thermal expansion of the drive shaft and the thermal expansion of the reactor vessel after the temperature rises gradually. Be done.

【0012】本発明はかかる従来の課題を解決するため
になされたもので、熱膨張効果の違いを利用した冷却材
温度上昇により大きな負の反応度を生じる反応度制御装
置を提供することを目的とする。
The present invention has been made in order to solve the above conventional problems, and an object of the present invention is to provide a reactivity control device which produces a large negative reactivity due to a rise in coolant temperature by utilizing the difference in thermal expansion effect. And

【0013】[0013]

【課題を解決するための手段】上記の目的を達成するた
めに、本発明の反応度制御装置は、ハンドリングヘッド
と下部入口ノズルを有する六角形状のラッパ管の内部
に、燃料要素と、反応度制御部を内蔵するナトリウム冷
却型高速増殖炉の反応度制御装置において、前記反応度
制御部は、熱膨張率の大きなワイヤと熱膨張率の小さな
外管からなる同軸ケーブルを熱膨張率の小さな軸に巻い
た部分と、前記ワイヤの先に取り付けられた中性子を良
く吸収する材料を含む吸収体とからなるものである。
In order to achieve the above object, the reactivity control device of the present invention comprises a fuel element and a reactivity inside a hexagonal trumpet tube having a handling head and a lower inlet nozzle. In the reactivity control device for a sodium-cooled fast breeder reactor with a built-in control unit, the reactivity control unit includes a coaxial cable composed of a wire having a large coefficient of thermal expansion and an outer tube having a small coefficient of thermal expansion and a shaft having a small coefficient of thermal expansion. And a absorber attached to the tip of the wire and containing a material that absorbs neutrons well.

【0014】[0014]

【作用】たとえば、反応度制御装置がなく、また、その
他の特別な考慮がなかった場合にも、通常は、多重の安
全設備により、事故時にも十分な裕度を持って、炉心の
健全性が確保される。しかし、極めて起こりにくいこと
ではあるが、前述のようなすべての制御棒の挿入も失敗
するようなケースを想定すると、冷却材の沸騰から、燃
料の被覆管の破損、更に炉心全体の崩壊に至る可能性が
ある。
[Function] For example, even if there is no reactivity control device and no other special consideration is taken, normally, multiple safety equipment provides a sufficient margin even in the event of an accident, thus ensuring the integrity of the core. Is secured. However, although it is extremely unlikely to occur, assuming the case where the insertion of all control rods as described above also fails, it will lead to boiling of the coolant, damage to the fuel cladding, and further collapse of the entire core. there is a possibility.

【0015】本発明の構成によれば、万一、何等かの異
常により、冷却材流量と出力の比(冷却材流量/出力)
が小さくなり、冷却材温度が上昇した場合、熱膨張率の
小さな軸5に巻かれた同軸ケーブル(図3)中の熱膨張
率の大きなワイヤ6が伸びて、ボロン等の中性子を良く
吸収する材料を含む吸収体7が炉心の中に挿入され、負
の反応度を生じ、炉心の出力が低下するように設計され
る。同軸ケーブルは、熱膨張率の大きなワイヤ6の伸び
が、たわみなどにより、その効果が小さくなるのを防止
するようになされている。
According to the configuration of the present invention, the ratio of the coolant flow rate to the output (coolant flow rate / output) should be due to some abnormality.
Becomes small and the coolant temperature rises, the wire 6 having a large coefficient of thermal expansion in the coaxial cable (FIG. 3) wound around the shaft 5 having a small coefficient of thermal expansion extends and absorbs neutrons such as boron well. The material-containing absorber 7 is designed to be inserted into the core, causing a negative reactivity and reducing the power of the core. The coaxial cable is configured to prevent the extension of the wire 6 having a large coefficient of thermal expansion from being reduced due to bending or the like.

【0016】[0016]

【実施例】図1は本発明の一実施例である反応度制御装
置の概念図である。また、図2は図1の上面断面図であ
る。
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a conceptual diagram of a reactivity control apparatus according to an embodiment of the present invention. 2 is a cross-sectional top view of FIG.

【0017】その構成は、図1,2から明かなように、
下部入口ノズル4、ラッパ管2、ハンドリングヘッド1
からなる六角形状の外形を有し、その内部に、燃料要素
3と反応度制御部8を内蔵する。
The structure is as shown in FIGS.
Lower inlet nozzle 4, trumpet tube 2, handling head 1
Has a hexagonal outer shape, in which the fuel element 3 and the reactivity control unit 8 are incorporated.

【0018】下部入口ノズル4は、通常の高速炉用燃料
集合体と同様に、冷却材を取り入れ、炉心支持板に装着
することにより反応度制御装置を支持する。
The lower inlet nozzle 4 supports a reactivity control device by taking in a coolant and mounting it on a core support plate, as in a normal fast reactor fuel assembly.

【0019】ラッパ管2は、通常の高速炉燃料集合体と
同じく、他の炉心構成要素と、冷却材流路を分離すると
ともに、構造的強度を保持するようになされる。また、
ハンドリングヘッド1は冷却材の出口であるとともに、
燃料交換機のつかみ代の役割を有する。
The trumpet tube 2 separates the coolant flow passage from other core constituent elements as well as the ordinary fast reactor fuel assembly, and maintains the structural strength. Also,
The handling head 1 is an outlet for the coolant, and
It has a role of holding the fuel refueling machine.

【0020】燃料要素3は、通常の高速炉用燃料要素と
同じく、Pu及びUを含むペレットをステンレス製の被
覆管に装填したものである。
The fuel element 3 is, like a fuel element for a normal fast reactor, a pellet containing Pu and U loaded in a stainless cladding tube.

【0021】反応度制御部8は、熱膨張率の大きなワイ
ヤ6と熱膨張率の小さな外管11からなる同軸ケーブル
を熱膨張率の小さな軸5に巻いた部分とワイヤ6の先に
取り付けられたボロン等の中性子を良く吸収する材料を
含む吸収体7とからなる。そして、定格運転時の吸収体
7の位置は炉心上端近傍にあるようにする。吸収体7の
下部及び支え板10により、冷却温度がある温度以上に
なった場合にも、吸収体が炉心の下側に移動しないよう
にする。また、反応度制御部8は、通常の炉心構成要素
と同様に、下部入口ノズル4が炉心支持板に装着されて
いるため、原子炉容器の熱膨張にともなって、炉心から
抜け出すことはない。
The reactivity control section 8 is attached to the tip of the wire 6 and the portion where the coaxial cable consisting of the wire 6 having a large coefficient of thermal expansion and the outer tube 11 having a small coefficient of thermal expansion is wound around the shaft 5 having a small coefficient of thermal expansion. And an absorber 7 containing a material such as boron that absorbs neutrons well. The position of the absorber 7 during the rated operation should be near the upper end of the core. The lower part of the absorber 7 and the support plate 10 prevent the absorber from moving to the lower side of the core even when the cooling temperature becomes higher than a certain temperature. Further, since the lower inlet nozzle 4 is attached to the core support plate, the reactivity control unit 8 does not come out of the reactor core due to the thermal expansion of the reactor vessel, as in the case of a normal core component.

【0022】同軸ケーブルは、熱膨張率の大きなワイヤ
6が熱膨張率の小さな外管11に収納されたもので、隙
間はわずかで、温度上昇をした場合、熱膨張率の差によ
り、熱膨張率の大きなワイヤ6が伸び、外管11により
途中でたわむことなく、軸方向に伸びる。
In the coaxial cable, the wire 6 having a large coefficient of thermal expansion is housed in the outer tube 11 having a small coefficient of thermal expansion, and there is a small gap. The wire 6 having a high rate is stretched, and is stretched in the axial direction without being bent by the outer tube 11 on the way.

【0023】長く熱膨張率の大きなワイヤ6を内部に含
み、熱膨張率の小さな外管11からなる同軸ケーブルを
熱膨張率の小さな軸5に巻くことにより、熱膨張による
吸収体7の挿入量を大きくする。熱膨張率の大きな材料
としてはSUS(1.7×10-5/℃)などがある。ま
た、熱膨張率の小さな材料としてはモリブデン(0.5
×10-5/℃)などがある。
By inserting a coaxial cable including a long wire 6 having a large coefficient of thermal expansion inside and an outer tube 11 having a small coefficient of thermal expansion around a shaft 5 having a small coefficient of thermal expansion, the amount of insertion of the absorber 7 due to thermal expansion. To increase. As a material having a large thermal expansion coefficient, there is SUS (1.7 × 10 −5 / ° C.) or the like. As a material having a small coefficient of thermal expansion, molybdenum (0.5
× 10 −5 / ° C.).

【0024】下部入口ノズルから取り入れられた冷却材
は燃料要素3の発熱により温度上昇し、熱膨張率の大き
なワイヤ6に熱を伝え、ワイヤ6の熱膨張を生じた後、
ハンドリングヘッド1から出る。ワイヤ6の伸びにより
その先端に取り付けられた吸収体7は下側に移動する。
The temperature of the coolant taken in from the lower inlet nozzle rises due to the heat generated by the fuel element 3, and the heat is transferred to the wire 6 having a large coefficient of thermal expansion to cause the thermal expansion of the wire 6,
Exit from handling head 1. The absorber 7 attached to the tip of the wire 6 moves downward due to the extension of the wire 6.

【0025】たとえば、冷却材が100℃温度上昇した
場合に、100cmの挿入量ΔLを得るため、SUSの
軸5とSUSの外管11とモリブデンのワイヤ6の組み
合わせで必要なワイヤ6の長さは、約833mとなる。
For example, when the temperature of the coolant rises by 100 ° C., in order to obtain the insertion amount ΔL of 100 cm, the length of the wire 6 required by the combination of the SUS shaft 5 and the SUS outer tube 11 and the molybdenum wire 6. Is about 833 m.

【0026】 ΔL = (1.7×10-5−0.5×10-5)(/℃) × 100 (℃) × 8.33×104(cm) = 100 (cm) 反応度制御装置の作用を図6に示す。反応度制御装置
は、図6(イ)に示すように、高速増殖炉の炉心の中に
通常の炉心燃料集合体と同じように装荷される。また、
燃料要素3には、核分裂性物質であるPuを含むため、
発熱しており、図6(ロ)に示すように、冷却材により
除熱されている。吸収体7は定格出力時には、炉心上端
にあるように設計されている。
ΔL = (1.7 × 10 -5 −0.5 × 10 −5 ) (/ ° C.) × 100 (° C.) × 8.33 × 10 4 (cm) = 100 (cm) Reactivity Control Device The action of is shown in FIG. As shown in FIG. 6A, the reactivity control device is loaded in the core of the fast breeder reactor in the same manner as a normal core fuel assembly. Also,
Since the fuel element 3 contains Pu which is a fissile material,
Heat is being generated, and as shown in FIG. 6B, the heat is removed by the coolant. The absorber 7 is designed to be at the upper end of the core at the rated output.

【0027】何らかの異常により、冷却材流量が減少、
あるいは出力が上昇した場合、まず、燃料要素3を除熱
している冷却材の温度が通常の炉心燃料集合体のものと
同様に上昇する。
Due to some abnormality, the coolant flow rate decreases,
Alternatively, when the output rises, first, the temperature of the coolant that removes heat from the fuel element 3 rises as in the case of a normal core fuel assembly.

【0028】この冷却材は、下流側で熱膨張率の大きな
ワイヤ6を含む同軸ケーブル(図3)と接しているた
め、熱は、ワイヤ6に伝えられ、ワイヤ6は熱膨張す
る。熱膨張率の小さな軸5と熱膨張率の小さな外管11
も膨張するが、熱膨張の違いから、ワイヤ6の熱膨張量
のほうが大きい。ワイヤ6の伸びは外管11の作用によ
りたわむことなく、軸方向に伸びて、ワイヤ6を外管1
1から出すように働く。ワイヤ6は、吸収体7をつり下
げているため、下側に引張られており、吸収体7は下側
に移動することになる。
Since this coolant is in contact with the coaxial cable (FIG. 3) including the wire 6 having a large coefficient of thermal expansion on the downstream side, heat is transferred to the wire 6 and the wire 6 thermally expands. Shaft 5 having a small coefficient of thermal expansion and outer tube 11 having a small coefficient of thermal expansion
However, the amount of thermal expansion of the wire 6 is larger due to the difference in thermal expansion. The extension of the wire 6 does not bend due to the action of the outer tube 11 and extends in the axial direction, so that the wire 6 is extended.
Work as if starting from 1. Since the wire 6 suspends the absorber 7, it is pulled downward, and the absorber 7 moves downward.

【0029】吸収体7が下側に移動し、炉心に挿入され
ると、吸収体7が吸収する中性子の割合が増え、負の反
応度が生じる。
When the absorber 7 moves downward and is inserted into the core, the proportion of neutrons absorbed by the absorber 7 increases and a negative reactivity is generated.

【0030】負の反応度により、炉心の出力は低下し、
冷却材流量/出力の比は大きくなり、炉心燃料集合体の
燃料及び冷却材の温度の上昇は抑制される。結果とし
て、異常は、燃料の破損を生じることなく、収束する。
Due to the negative reactivity, the core power decreases,
The coolant flow rate / power ratio is increased, and the temperature rise of the fuel and the coolant of the core fuel assembly is suppressed. As a result, the anomaly converges without causing fuel damage.

【0031】図6及び図8は、反応度制御装置を含む高
速増殖炉の炉心の例を示した図で、以下これについて、
説明する。6個の反応度制御装置が、炉心の中に置かれ
ている。吸収体7が完全に挿入された場合、2.5%Δ
k/kの反応度価値を有している。熱膨張率の大きなワ
イヤ6はSUS、熱膨張率の小さな軸5と熱膨張率の小
さな外管11は、モリブデンを用い、ワイヤ6の長さを
833mとする。その他、冷却材は、ナトリウム(N
a)とし、0%出力から定格出力までの反応度変化は、
1.0%Δk/kである。
FIGS. 6 and 8 are views showing examples of the core of a fast breeder reactor including a reactivity control device.
explain. Six reactivity control devices are located in the core. 2.5% Δ when absorber 7 is fully inserted
It has a reactivity value of k / k. The wire 6 having a large thermal expansion coefficient is made of SUS, the shaft 5 having a small thermal expansion coefficient and the outer tube 11 having a small thermal expansion coefficient are made of molybdenum, and the length of the wire 6 is set to 833 m. In addition, the coolant is sodium (N
a) and the change in reactivity from 0% output to rated output is
It is 1.0% Δk / k.

【0032】この反応度制御装置を含む高速増殖炉が定
格出力運転中に、冷却材を流すためのポンプが動力を失
い、しかも、通常の多重の安全装置が作動せず、原子炉
が停止しなかった場合、以下のように事象は推移する。
During the rated output operation of the fast breeder reactor including this reactivity control device, the pump for flowing the coolant loses power, and the normal multiple safety device does not operate, and the reactor is stopped. If not, the event proceeds as follows.

【0033】 冷却材流量/出力が小さくなり、冷却
温度が上昇する。
The coolant flow rate / output is reduced and the cooling temperature is increased.

【0034】 冷却温度が上昇すると、ワイヤ6、軸
5及び外管11はそれぞれ伸びるが、熱膨張率の差から
ワイヤ6の伸びがより大きい。(外管11の作用によ
り、ワイヤ6はたわまず、そのまま下側にでる。・・・
図6(ロ)参照。) ワイヤ6が伸びて吸収体7が下がる。・・・図6
(イ)参照。
When the cooling temperature rises, the wire 6, the shaft 5 and the outer tube 11 respectively expand, but the elongation of the wire 6 is larger due to the difference in the coefficient of thermal expansion. (Due to the action of the outer tube 11, the wire 6 does not bend, but goes out to the lower side.
See FIG. 6B. ) The wire 6 extends and the absorber 7 descends. ... Figure 6
See (a).

【0035】 吸収体7が炉心に挿入され、負の反応
度が入る。結果として、出力が低下する。
The absorber 7 is inserted into the core and a negative reactivity is introduced. As a result, the output is reduced.

【0036】 反応度制御装置の挿入反応度は、熱膨
張による吸収体の挿入量により、図7のように変化す
る。
The insertion reactivity of the reactivity control device changes as shown in FIG. 7 depending on the amount of the absorber inserted due to thermal expansion.

【0037】 冷却材流量が自然循環による流れ(定
格流量の数%)のみまで減少すると、〜の作用によ
り、反応度制御装置の出口冷却材温度が45℃上昇し、 (1.7×10-5−0.5×10-5)(/℃) × 45 (℃) × 8.33×104(cm) = 45 (cm) ワイヤ6は、軸5や外管11にくらべ45cm長く伸
び、吸収体7は炉心に45cm挿入され、負の反応度が
1.0%Δk/k生じる(図7参照)。
When the coolant flow rate is reduced to only the flow by natural circulation (several percent of the rated flow rate), the action of causes the outlet coolant temperature of the reactivity control device to rise by 45 ° C., and (1.7 × 10 5 -0.5 × 10 -5) (/ ℃) × 45 (℃) × 8.33 × 10 4 (cm) = 45 (cm) wire 6, 45cm elongated compared to the shaft 5 and the outer tube 11, The absorber 7 is inserted 45 cm into the core, and a negative reactivity of 1.0% Δk / k occurs (see FIG. 7).

【0038】 負の反応度が1.0%Δk/kまで大
きくなると、連鎖反応による炉心の出力は0%まで低下
し、発熱は、崩壊熱のみとなる。
When the negative reactivity increases to 1.0% Δk / k, the core output due to the chain reaction decreases to 0%, and the only exothermic heat is decay heat.

【0039】 炉心の崩壊熱は、Naの優れた自然循
環力により、除熱される。このため、冷却材温度は沸点
を超えない。
The decay heat of the core is removed by the excellent natural circulation force of Na. Therefore, the coolant temperature does not exceed the boiling point.

【0040】 〜までの事象推移における炉心内
での燃料の冷却材最高温度は事象の推移の速さにより、
特に炉心内の冷却材流量の低下する割合により変わる
が、十分にゆっくりであったと仮定すると、反応度制御
装置の冷却材出口温度と炉心内の冷却材最高温度の次の
関係から、763℃と推定される。
The maximum coolant temperature of the fuel in the core in the event transitions up to is determined by the speed of the event transition,
In particular, it depends on the rate of decrease of the coolant flow rate in the core, but if it is assumed to be sufficiently slow, from the following relationship between the coolant outlet temperature of the reactivity control device and the maximum coolant temperature in the core, Presumed.

【0041】 Tc − Tin ∝ Tmax − Tin ここで、Tc : 反応度制御装置の冷却材出口温度 Tin : 炉心入口冷却材温度 Tmax: 燃料の冷却材最高温度 Tmax = {(Tmax°−Tin)/(Tc°−Tin)} × (Tc−Tin)+Tin ここで、T°は定格時の温度の値を示す。Tc-Tin ∝ Tmax-Tin Here, Tc: coolant outlet temperature of the reactivity control device Tin: core inlet coolant temperature Tmax: maximum coolant temperature of fuel Tmax = {(Tmax ° -Tin) / ( Tc ° −Tin)} × (Tc−Tin) + Tin Here, T ° represents the value of the temperature at the time of rating.

【0042】 Tmax = {(700−355)/(600−355)} × (645−355)+355 = 763(℃) 以上、〜の事象推移の結果、燃料の冷却材最高温度
は、炉心内でNaの沸点約930℃を超えない。
Tmax = {(700-355) / (600-355)} × (645-355) + 355 = 763 (° C.) As a result of the above event transitions, the maximum temperature of the coolant of the fuel is in the core. The boiling point of Na does not exceed about 930 ° C.

【0043】[0043]

【発明の効果】本発明の反応度制御装置を含む高速増殖
炉の炉心において、炉心に冷却材を流すためのポンプが
停止し、かつ、制御棒が挿入されなかったような場合に
ついて、反応度制御装置の効果を述べる。まず、反応度
制御装置の出口冷却材温度は徐々に上昇し、645℃に
到達したとき、ワイヤ6が伸び、吸収体が約45cm挿
入され、炉心に1.0%Δk/kの負の反応度が挿入さ
れ、連鎖反応による出力は、0%まで低下し、崩壊熱の
みとなる。この時燃料の冷却材最高温度は、約763℃
くらいまで上昇するが、炉心内でのNaの沸点約930
℃に到達することはなく、冷却材の沸騰及び燃料の被覆
管の破損を生じずに、事象は静定すると推測される。
EFFECT OF THE INVENTION In the core of a fast breeder reactor including the reactivity control device of the present invention, when the pump for flowing the coolant into the core is stopped and the control rod is not inserted, the reactivity is reduced. The effect of the control device will be described. First, the outlet coolant temperature of the reactivity control device gradually rises, and when it reaches 645 ° C., the wire 6 is extended, the absorber is inserted about 45 cm, and the negative reaction of 1.0% Δk / k is introduced into the core. Degree is inserted, the output due to the chain reaction decreases to 0%, and there is only decay heat. At this time, the maximum temperature of the fuel coolant is approximately 763 ° C.
The boiling point of Na in the core is about 930
It is assumed that the event does not reach 0 ° C. and the event settles without boiling the coolant and breaking the cladding of the fuel.

【0044】したがって、深層防護の観点から、反応度
制御装置は、高速増殖炉の炉心の安全性向上に寄与す
る。
Therefore, from the viewpoint of defense in depth, the reactivity control device contributes to the improvement of the safety of the core of the fast breeder reactor.

【図面の簡単な説明】[Brief description of drawings]

【図1】本発明の一実施例である反応度制御装置の概念
図である。
FIG. 1 is a conceptual diagram of a reactivity control device that is an embodiment of the present invention.

【図2】図1の上面断面図である。FIG. 2 is a top sectional view of FIG.

【図3】本発明の一実施例である同軸ケーブルの構造を
説明する図である。
FIG. 3 is a diagram illustrating the structure of a coaxial cable that is an embodiment of the present invention.

【図4】従来の技術の一実施例である制御棒駆動軸の熱
膨張効果の説明図である。
FIG. 4 is an explanatory diagram of a thermal expansion effect of a control rod drive shaft that is an example of a conventional technique.

【図5】従来の技術の一実施例である制御棒吸収体の位
置とその効果の関係の説明図である。
FIG. 5 is an explanatory diagram of the relationship between the position of a control rod absorber and its effect, which is one example of the conventional technique.

【図6】本発明の一実施例である反応度制御装置の作用
の説明図である。
FIG. 6 is an explanatory view of the operation of the reactivity control device which is one embodiment of the present invention.

【図7】本発明の一実施例である反応度制御装置の挿入
反応度を示す図である。
FIG. 7 is a diagram showing insertion reactivity of the reactivity control device according to the embodiment of the present invention.

【図8】本発明の一実施例である反応度制御装置の特性
を示す図表である。
FIG. 8 is a chart showing characteristics of a reactivity control device according to an embodiment of the present invention.

【符号の説明】[Explanation of symbols]

1 ハンドリングヘッド 2 ラッパ管 3 燃料要素 4 下部入口ノズル 5 熱膨張率の小さな軸 6 熱膨張率の大きなワイヤ 7 吸収体 8 反応度制御部 9 流路の隔壁 10 支え板 11 外管 1 Handling Head 2 Trumpet Pipe 3 Fuel Element 4 Lower Inlet Nozzle 5 Shaft with Small Thermal Expansion Coefficient 6 Wire with Large Thermal Expansion Coefficient 7 Absorber 8 Reactivity Control Section 9 Partition Wall 10 Support Plate 11 Outer Tube

Claims (1)

【特許請求の範囲】[Claims] 【請求項1】 ハンドリングヘッドと下部入口ノズルを
有する六角形状のラッパ管の内部に、燃料要素と、反応
度制御部を内蔵するナトリウム冷却型高速増殖炉の反応
度制御装置において、前記反応度制御部は、熱膨張率の
大きなワイヤと熱膨張率の小さな外管からなる同軸ケー
ブルを熱膨張率の小さな軸に巻いた部分と、前記ワイヤ
の先に取り付けられた中性子を良く吸収する材料を含む
吸収体とからなることを特徴とする反応度制御装置。
1. A reactivity control device for a sodium-cooled fast breeder reactor, comprising a fuel element and a reactivity control unit inside a hexagonal trumpet tube having a handling head and a lower inlet nozzle, wherein the reactivity control is performed. The part includes a portion in which a coaxial cable consisting of a wire having a large coefficient of thermal expansion and an outer tube having a small coefficient of thermal expansion is wound around an axis having a small coefficient of thermal expansion, and a material attached to the tip of the wire that absorbs neutrons well. A reactivity control device comprising an absorber.
JP50A 1993-01-28 1993-01-28 Reactivity controller Withdrawn JPH06222178A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP50A JPH06222178A (en) 1993-01-28 1993-01-28 Reactivity controller

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP50A JPH06222178A (en) 1993-01-28 1993-01-28 Reactivity controller

Publications (1)

Publication Number Publication Date
JPH06222178A true JPH06222178A (en) 1994-08-12

Family

ID=12323165

Family Applications (1)

Application Number Title Priority Date Filing Date
JP50A Withdrawn JPH06222178A (en) 1993-01-28 1993-01-28 Reactivity controller

Country Status (1)

Country Link
JP (1) JPH06222178A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015500993A (en) * 2011-12-06 2015-01-08 テラパワー, エルエルシー Reactivity control device and control method in nuclear fission reactor, nuclear fission reactor, and method for manufacturing reactivity control device
CN110073443A (en) * 2016-12-22 2019-07-30 泰拉能源公司 Dependent response control in fission-type reactor
CN112366009A (en) * 2020-11-16 2021-02-12 中国原子能科学研究院 Mixed winding and wire winding positioning fuel assembly of sodium-cooled fast reactor

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015500993A (en) * 2011-12-06 2015-01-08 テラパワー, エルエルシー Reactivity control device and control method in nuclear fission reactor, nuclear fission reactor, and method for manufacturing reactivity control device
CN110073443A (en) * 2016-12-22 2019-07-30 泰拉能源公司 Dependent response control in fission-type reactor
CN112366009A (en) * 2020-11-16 2021-02-12 中国原子能科学研究院 Mixed winding and wire winding positioning fuel assembly of sodium-cooled fast reactor
CN112366009B (en) * 2020-11-16 2023-01-10 中国原子能科学研究院 Mixed winding and wire winding positioning fuel assembly of sodium-cooled fast reactor

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