JP2633107B2 - Method for producing boron / carbon composite neutron shielding material - Google Patents
Method for producing boron / carbon composite neutron shielding materialInfo
- Publication number
- JP2633107B2 JP2633107B2 JP3132675A JP13267591A JP2633107B2 JP 2633107 B2 JP2633107 B2 JP 2633107B2 JP 3132675 A JP3132675 A JP 3132675A JP 13267591 A JP13267591 A JP 13267591A JP 2633107 B2 JP2633107 B2 JP 2633107B2
- Authority
- JP
- Japan
- Prior art keywords
- boron
- carbon composite
- pitch
- temperature
- strength
- 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.)
- Expired - Lifetime
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Classifications
-
- Y—GENERAL 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
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- Ceramic Products (AREA)
- Carbon And Carbon Compounds (AREA)
Description
【0001】[0001]
【産業上の利用分野】本発明は、中性子吸収性能、熱的
および機械的性質に優れ、かつ高強度のホウ素/炭素複
合材の製造方法に関する。本発明によるホウ素/炭素複
合材は、原子炉容器内炉心周り中性子遮蔽体、炉心内制
御棒等の構成材料として適している。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a boron / carbon composite material having excellent neutron absorption performance, thermal and mechanical properties, and high strength. The boron / carbon composite material according to the present invention is suitable as a constituent material for a neutron shield around a core in a reactor vessel, a control rod in a core, and the like.
【0002】[0002]
【従来の技術】従来より、中性子吸収性能、熱的および
機械的性質に優れたホウ素/炭素複合材の製造方法とし
ては各種のものが提案されている。たとえば、第1の方
法としては、特開昭52−105917号公報にコーク
スと炭化ホウ素を200kg/cm2以上の加圧下で、かつ2
000℃以上で焼結する方法の開示がある。また、第2
の方法としては、特開昭54−81315号公報に炭化
ホウ素(B4 C)25〜60体積%、遊離炭素50〜5
体積%からなり、熱硬化性樹脂で結合された密度1.4
〜1.8g/cm3 の炭化ホウ素/炭素複合材の製造方法の
開示がある。また、第3の方法としては、特開昭62−
108767号公報にピッチを熱処理して生成したメソ
フェーズ小球体100重量部と、耐熱性無機材質粒子
(炭化ホウ素B4 C)1〜50重量部を常温で成型後、
焼成する方法の開示がある。さらに、第4の方法として
は、第3の方法の改良方法に係り、特開平1−1000
63号公報にメソフェーズ小球体を粉砕して微粉化する
とともに、焼成時に減圧し、焼結助材として人造黒鉛を
添加して強度増加を図る方法の開示がある。2. Description of the Related Art Conventionally, various methods have been proposed for producing a boron / carbon composite material having excellent neutron absorption performance, thermal and mechanical properties. For example, as a first method, Japanese Patent Application Laid-Open No. Sho 52-105917 discloses coke and boron carbide under a pressure of 200 kg / cm 2 or more and for 2 hours.
There is a disclosure of a method of sintering at 000 ° C. or higher. Also, the second
As methods, (4 C B) 25~60 vol% boron carbide in JP-A-54-81315, free carbon 50-5
% By volume, bound by thermosetting resin 1.4
It is disclosed of a method for manufacturing a boron carbide / carbon composite material of ~1.8g / cm 3. A third method is disclosed in
No. 108767, 100 parts by weight of mesophase spheres produced by heat-treating pitch and 1 to 50 parts by weight of heat-resistant inorganic material particles (boron carbide B 4 C) are molded at room temperature.
There is disclosure of a firing method. Further, the fourth method relates to an improved method of the third method.
No. 63 discloses a method of pulverizing and pulverizing mesophase small spheres, reducing the pressure during firing, and adding artificial graphite as a sintering aid to increase the strength.
【0003】[0003]
【発明が解決しようとする課題】しかし、前記第1の方
法の場合には2000℃以上の超温度で加圧成型する必
要があり、この加圧加熱成型設備が極めて高価であるた
め経済的でないなどの問題を有する。また、第2方法の
場合には、結合材として熱硬化性樹脂を使用しており、
樹脂の炭化収率が低いため比較的低密度であり、強度増
加が望めないとともに、樹脂由来の炭素は不定型であり
機械加工性、潤滑性が不良であるなどの問題を有する。
また、第3の方法の場合には、得られる複合材の強度レ
ベルが低く、また中性子吸収率を上げるために炭化ホウ
素の体積含有率を増加させると複合材の強度が低下する
ため、高強度かつ高中性子吸収能を有する複合材を得る
ことは困難であった。さらに第4の方法の場合にも、あ
る程度の強度増加は望めるもののB4 C含有率が高々5
5重量%で、曲げ強度も520kg/cm2と比較的低いもの
であった。However, in the case of the first method, it is necessary to carry out pressure molding at a super-temperature of 2000 ° C. or more. Etc. In the case of the second method, a thermosetting resin is used as a binder,
Since the carbonization yield of the resin is low, the resin has a relatively low density, an increase in strength cannot be expected, and the carbon derived from the resin is irregular and has problems such as poor machinability and lubricity.
Further, in the case of the third method, the strength level of the obtained composite material is low, and when the volume content of boron carbide is increased in order to increase the neutron absorption, the strength of the composite material is reduced. And it was difficult to obtain a composite material having a high neutron absorption capacity. Further, in the case of the fourth method, although a certain increase in strength can be expected, the B 4 C content is at most 5%.
At 5% by weight, the flexural strength was relatively low at 520 kg / cm 2 .
【0004】そこで、本発明の主たる課題は、中性子吸
収性能および曲げ強度等の機械的性質に優れたホウ素/
炭素複合材を廉価に製造する方法を提供するものであ
る。[0004] Accordingly, a main object of the present invention is to provide a boron / boron compound having excellent mechanical properties such as neutron absorption performance and bending strength.
An object of the present invention is to provide a method for producing a carbon composite material at low cost.
【0005】[0005]
【課題を解決するための手段】前記課題は、ホウ素およ
び炭化ホウ素の一種または二種の粉末60〜85体積%
と、バインダーピッチ15〜40体積%とを主体とする
原料を混合し、480〜600℃の温度で加圧加熱成型
後、非加圧下で焼成することで解決できる。The object of the present invention is to provide one or two kinds of powders of boron and boron carbide in an amount of 60 to 85% by volume.
This can be solved by mixing a raw material mainly composed of 15 to 40% by volume with a binder pitch of 15 to 40% by volume, pressurizing and heating at a temperature of 480 to 600 ° C., and then baking under no pressure.
【0006】[0006]
【作用】本発明においては、バインダーとして加熱時溶
融する低揮発分のバインダーピッチを使用する。溶融性
の良好なピッチを使用することによりセラミックス粉に
対するバインダー性が改善され、多量のセラミックス粉
を添加してもバインダー性が不足することがなくなり、
強度の低下が少なくなるとともに、揮発分が少ないこと
により炭化収率が向上するため複合材の密度ならびに強
度増加を図ることができる。また、バインダーピッチの
使用により炭素マトリックスは容易に黒鉛化性組織とな
りその後2000℃程度で焼成することにより摺動特性
および加工性に優れた黒鉛組織となる。なお、前記バイ
ンダーピッチとしては、コールタールピッチや石油ピッ
チを熱処理して得られる、高軟化点でかつ流動性を有す
る低揮発分のバインダーピッチ、具体的には、揮発分2
5%以下、軟化点(島津製作所(株)社製高化式フロー
テスターでの測定値)が230℃以上、流動点350℃
以下のピッチを使用するのが望ましい。また、その添加
量は15〜40体積%とされる。15体積%未満の場合
には十分な接着力が得られず強度増加が望めず、また4
0体積%を超えるとホウ素または炭化ホウ素の含有割合
の低下により中性子吸収能が低下し、またバインダーが
過剰となり成型性が悪化するため強度が低下する。In the present invention, a binder pitch having a low volatile content, which melts when heated, is used as the binder. By using a pitch having good melting property, the binder property to the ceramic powder is improved, and even if a large amount of ceramic powder is added, the binder property does not become insufficient,
The decrease in strength is reduced, and the carbonization yield is improved due to less volatile components, so that the density and strength of the composite material can be increased. In addition, the use of the binder pitch makes the carbon matrix easily a graphitizable structure, and then firing at about 2000 ° C. results in a graphite structure having excellent sliding characteristics and workability. The binder pitch is a binder pitch obtained by heat-treating coal tar pitch or petroleum pitch and having a high softening point and a low volatile content.
5% or less, softening point (measured value by Koka type flow tester manufactured by Shimadzu Corporation) is 230 ° C or more, pour point 350 ° C
It is desirable to use the following pitch: Further, the addition amount is 15 to 40% by volume. If the content is less than 15% by volume, sufficient adhesive strength cannot be obtained, and no increase in strength can be expected.
If the content exceeds 0% by volume, the neutron absorption ability decreases due to the decrease in the content of boron or boron carbide, and the binder decreases due to excess binder and moldability.
【0007】なお、前記ホウ素含有粉末粉とバインダー
ピッチに加え、さらに炭素繊維、アルミナ繊維等のセラ
ミックス繊維を、20体積%以下の範囲で添加すること
も可能である。前記繊維の添加により成型から焼成時の
割れの抑制や、製品としての靱性の向上などを図ること
ができる。[0007] In addition to the boron-containing powder and the binder pitch, ceramic fibers such as carbon fibers and alumina fibers can be added in a range of 20% by volume or less. By the addition of the fibers, it is possible to suppress cracks from molding to firing and to improve toughness as a product.
【0008】一方、本発明で用いられるホウ素含有粉末
粉としては、ホウ素および炭化ホウ素の一種または二種
の粉末60〜85体積%を使用する。高い中性子吸収能
を確保するためには、少なくともその添加率が60体積
%以上必要であり、一方85体積%を超えると、バイン
ダーピッチが15体積%以下となり強度が低下する。ま
た、前記ホウ素含有粉末粉の粒径は、大き過ぎると複合
材の強度が著しく低下するため、好ましくは平均粒径で
20μm以下、より好ましくは10μm以下とされる。On the other hand, as the boron-containing powder used in the present invention, one or two kinds of powders of boron and boron carbide are used in an amount of 60 to 85% by volume. In order to ensure a high neutron absorption capacity, the addition rate must be at least 60% by volume or more, while if it exceeds 85% by volume, the binder pitch becomes 15% by volume or less and the strength is reduced. If the particle size of the boron-containing powder is too large, the strength of the composite material is significantly reduced. Therefore, the average particle size is preferably 20 μm or less, more preferably 10 μm or less.
【0009】他方、加圧加熱成型の目的は、ピッチの発
泡およびそれに起因する低密度化を抑制し緻密性を担保
するためである。加圧はピッチが溶融〜固化する温度域
のみで行えばよいため、本発明の場合には480〜60
0℃の温度で加圧加熱成型し、その後非加圧下で高温焼
成する。ピッチが固化するためには少なくとも480℃
以上、好ましくは500℃以上の温度が必要であり、ま
た600℃を超えるとピッチの収縮に伴う成型体の収縮
が大きくなり、加圧拘束下では成型体に割れが生じ易く
なるため好ましくない。[0009] On the other hand, the purpose of pressurized heat molding is to suppress foaming of the pitch and the resulting decrease in density and to ensure denseness. Pressing may be performed only in a temperature range in which the pitch is melted to solidified.
It is pressurized and heated at a temperature of 0 ° C., and then fired at a high temperature under no pressure. At least 480 ° C for the pitch to solidify
As described above, a temperature of preferably 500 ° C. or more is required, and if the temperature exceeds 600 ° C., shrinkage of the molded body accompanying shrinkage of the pitch becomes large, and cracks tend to occur in the molded body under pressure constraint, which is not preferable.
【0010】本発明での加圧成型は、高々数十〜数百kg
/cm2程度あれば十分であり、具体的には好ましくは20
kg/cm2以上、より好ましくは60kg/cm2以上とされる。
ここで、加圧する温度範囲については、室温状態から加
圧加熱最高温度までの全範囲である必要はなく、最高温
度に達するまでの一部の温度範囲、具体的にはピッチが
固化する500℃近傍の温度域において加圧するだけで
も、加圧加熱成型しない場合に比較して製品複合材の強
度、耐摩耗性などを著しく改善することができる。The pressure molding in the present invention is at most several tens to several hundreds kg.
/ cm 2 is sufficient, and specifically, preferably 20
kg / cm 2 or more, more preferably 60 kg / cm 2 or more.
Here, the temperature range to be pressurized does not need to be the entire range from the room temperature state to the maximum pressurized heating temperature, but a part of the temperature range until reaching the maximum temperature, specifically 500 ° C. at which the pitch solidifies. Even when pressure is applied only in the vicinity of the temperature range, the strength, wear resistance, and the like of the product composite material can be remarkably improved as compared with the case where pressure and heat molding is not performed.
【0011】加圧加熱成型によって得られた前記成型体
を、その後非加圧下で、たとえば2000℃程度の温度で焼
成するが、焼成時の雰囲気は、複合材中の炭素の酸化を
抑制するため、酸化性ガスを含まないことが望ましい。
具体的には、窒素、アルゴン等の不活性ガス、水素等の
還元ガス、あるいは真空雰囲気で行うことが望ましい。The molded body obtained by pressurized heat molding is then fired under non-pressure at a temperature of, for example, about 2000 ° C. The firing atmosphere is to suppress the oxidation of carbon in the composite material. It is desirable not to contain an oxidizing gas.
Specifically, it is desirable to carry out in an inert gas such as nitrogen or argon, a reducing gas such as hydrogen, or a vacuum atmosphere.
【0012】以上の方法により製造されるホウ素/炭素
複合材は、従来の常温焼結法や、樹脂マトリックス法と
比べて、高いホウ素含有粉末含有率と強度を有し、中性
子吸収能、熱的および機械的性質に優れる。また、加圧
加熱成型温度は、600℃以下の温度で足りるため、従
来のような1600℃以上の超高温域まで加熱し加圧す
るホットプレス成型と比べて、加圧加熱成型装置設備が
非常に安価となり経済的に有利となる。The boron / carbon composite material produced by the above-described method has a higher boron-containing powder content and strength, a higher neutron absorption capability, and a higher thermal conductivity than conventional cold sintering and resin matrix methods. And excellent mechanical properties. In addition, since the pressing and heating molding temperature is sufficient at 600 ° C. or less, compared to the conventional hot press molding that heats and presses to an extremely high temperature range of 1600 ° C. or more, the equipment of the heating and heating molding equipment is very much required. Inexpensive and economically advantageous.
【0013】[0013]
【実施例】以下、本発明の効果を実施例に基づき詳説す
る。 (実施例1)ホウ素含有粉末粉として、電気化学工業
(株)製B4 C粉〔商標名;デンカボロンF1〕(ホウ
素含有率75wt%以上、C含有量20〜25wt%、公称
粒径10μm以下)と、バインダーピッチとしてコール
タールを50Torr減圧の下で440℃で熱処理して得ら
れた軟化点255℃、流動点310℃、揮発分21%の
高軟化点ピッチとを用いて、本発明に係るホウ素/炭素
複合材を製造した。The effects of the present invention will be described below in detail with reference to examples. (Example 1) boron-containing powder powder, Denki Kagaku Kogyo Co., Ltd. B 4 C powder [trade name; Denkaboron F1] (boron content 75 wt% or more, C content 20~25Wt%, or less nominal particle size of 10μm ), And a high softening point pitch having a softening point of 255 ° C, a pour point of 310 ° C, and a volatile matter of 21% obtained by heat-treating coal tar at 440 ° C under a reduced pressure of 50 Torr as a binder pitch. Such a boron / carbon composite was produced.
【0014】具体的には、B4 C粉164gと高軟化点
ピッチ36gを秤量後、内容積2lのポリ製広口ビンに
入れ、5分間激しく振って混合し、この混合原料を図1
に示される加圧加熱成型装置の内径100mmのステンレ
ス製金枠5に仕込み、加圧加熱成型を行った。Specifically, 164 g of B 4 C powder and 36 g of a high softening point pitch were weighed, placed in a 2 liter poly wide-mouth bottle having an internal volume of 2 liters, and vigorously shaken for 5 minutes to mix.
Was placed in a stainless steel metal frame 5 having an inner diameter of 100 mm of a pressurizing and heating molding apparatus shown in (1) to perform pressurizing and heating molding.
【0015】前記加圧加熱成型装置は、金枠5の上下開
口に嵌合する上下金型3、4により成型材料6を押圧成
型するとともに、前記上下金型3、4と上下プレスヘッ
ド1、2との間に熱板7、7およびその断熱材8、8を
介在させることによって加圧と同時に加熱できるように
なっている。The pressurizing and heating molding apparatus press-molds a molding material 6 by means of upper and lower molds 3 and 4 fitted into upper and lower openings of a metal frame 5, and simultaneously forms the upper and lower molds 3 and 4 with an upper and lower press head 1. By interposing the heat plates 7, 7 and the heat insulating materials 8, 8 between them, the heating can be performed simultaneously with the pressurization.
【0016】前記加圧加熱成型装置により加圧加熱成型
に際しては、室温から300℃までは1kg/cm2のプレス
圧の下で5℃/分の昇温速度で昇温させ、300℃〜5
20℃までは80kg/cm2のプレス圧の下で5℃/Hrの昇
温速度で昇温し、1時間その状態を保持した後、冷却し
成型体を得、この成型体を粉コークスに詰め、窒素ガス
雰囲気中で15℃/Hrの昇温速度で1000℃まで昇温
し、4時間保持後放冷して炭化し、次にこの炭化した成
型体を、内径150mmφの黒鉛化炉を用いてアルゴン気
流中10℃/分の昇温速度で2000℃まで昇温して黒
鉛化した。こうして得られたホウ素/炭素複合材から寸
法10mm×10mm×60mmの試験片を切り出し、曲げ強
度(スパン40mm)およびショア硬度試験を行った。そ
の試験結果を表1に示す。In the pressurized heat molding by the above pressurized heat molding apparatus, the temperature is raised from room temperature to 300 ° C. under a press pressure of 1 kg / cm 2 at a rate of 5 ° C./min.
The temperature was raised at a rate of 5 ° C./Hr under a press pressure of 80 kg / cm 2 until the temperature reached 20 ° C., and after maintaining the state for 1 hour, a compact was obtained by cooling. In a nitrogen gas atmosphere, the temperature was raised to 1000 ° C. at a temperature rising rate of 15 ° C./Hr, kept for 4 hours, allowed to cool, and then carbonized. Then, the carbonized molded product was subjected to a graphitization furnace having an inner diameter of 150 mmφ. The mixture was heated to 2000 ° C. in an argon stream at a rate of 10 ° C./min to graphitize. A test piece having a size of 10 mm × 10 mm × 60 mm was cut out from the boron / carbon composite material thus obtained, and a bending strength (span of 40 mm) and a Shore hardness test were performed. Table 1 shows the test results.
【0017】[0017]
【表1】 [Table 1]
【0018】上記表1より明らかとなるように、公知の
製造方法(特開昭54-81315号公報、特開平1-100063 号
公報)の場合には前述の如く、高々500kg/cm2程度で
あるのに対して、本発明法によるホウ素/炭素複合材の
場合には、1500kg/cm2程度の曲げ強度を確保するこ
とができ、優れた強度性を有することが判明される。As is clear from the above Table 1, in the case of the known production methods (Japanese Patent Application Laid-Open No. 54-81315 and Japanese Patent Application Laid-Open No. 1-100063), as described above, at most about 500 kg / cm 2 . On the other hand, in the case of the boron / carbon composite material according to the method of the present invention, a bending strength of about 1500 kg / cm 2 can be secured, and it has been found that the material has excellent strength.
【0019】[0019]
【発明の効果】以上詳説のとおり、本発明に係るホウ素
/炭素複合材の場合には、ホウ素含有率を高く設定し中
性子吸収能を確保しながら、かつ高曲げ強度を確保する
ことができ、たとえば原子炉用中性子吸収材として好適
な中性子遮蔽材を得ることができる。また、極めて低温
域での加熱成型であるため加圧加熱成型装置が簡単かつ
廉価となり、それがもたす経済効果も多大である。As described above in detail, in the case of the boron / carbon composite material according to the present invention, it is possible to secure a high bending strength while securing a neutron absorbing ability by setting a high boron content. For example, a neutron shielding material suitable as a neutron absorbing material for a nuclear reactor can be obtained. Further, since the heat molding is carried out in an extremely low temperature range, the pressure and heat molding apparatus is simple and inexpensive, and the economic effect provided by the apparatus is great.
【図1】実施例で使用した加圧加熱成型装置の縦断面図
である。FIG. 1 is a longitudinal sectional view of a pressurized heat molding apparatus used in an example.
1…上プレスヘッド、2…下プレスヘッド、3…上金
型、4…下金型、5…金枠、6…成型材料、7…熱板、
8…断熱材DESCRIPTION OF SYMBOLS 1 ... Upper press head, 2 ... Lower press head, 3 ... Upper mold, 4 ... Lower mold, 5 ... Metal frame, 6 ... Molding material, 7 ... Hot plate,
8… Insulation material
フロントページの続き (72)発明者 野村 茂雄 茨城県東茨城郡大洗町成田町4002 動力 炉・核燃料開発事業団大洗工学センター 内 (72)発明者 角南 好彦 東京都千代田区大手町一丁目1番3号 住友金属工業株式会社内 (72)発明者 酢谷 潔 大阪市中央区北浜4丁目5番33号 住友 金属工業株式会社内 (56)参考文献 特開 昭48−42009(JP,A) 特開 昭54−81315(JP,A) 特開 昭58−172584(JP,A) 特開 昭62−108767(JP,A) 特開 平1−100063(JP,A) 特開 平2−181694(JP,A) 特開 平4−2659(JP,A)Continuation of the front page (72) Inventor Shigeo Nomura 4002 Narita-cho, Oarai-machi, Higashiibaraki-gun, Ibaraki Prefecture Inside the Oarai Engineering Center of the Reactor and Nuclear Fuel Development Corporation (72) Inventor Yoshihiko Sumunami 1-3-1 Otemachi, Chiyoda-ku Tokyo No. Sumitomo Metal Industries, Ltd. (72) Inventor Kiyoshi Sugitani 4-33, Kitahama, Chuo-ku, Osaka-shi Sumitomo Metal Industries, Ltd. (56) References JP-A-48-42009 (JP, A) JP-A-54-81315 (JP, A) JP-A-58-172584 (JP, A) JP-A-62-108767 (JP, A) JP-A-1-100063 (JP, A) JP-A-2-181694 (JP) , A) JP-A-4-2659 (JP, A)
Claims (1)
の粉末60〜85体積%と、バインダーピッチ15〜4
0体積%とを主体とする原料を混合し、480〜600
℃の温度で加圧加熱成型後、非加圧下で焼成することを
特徴とするホウ素/炭素複合系中性子遮蔽材の製造方
法。A powder of one or two of boron and boron carbide in an amount of 60 to 85% by volume and a binder pitch of 15 to 4%.
0% by volume and a mixture of 480 to 600
A method for producing a boron / carbon composite-based neutron shielding material, characterized in that after heating under pressure at a temperature of ° C., the mixture is fired under no pressure.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3132675A JP2633107B2 (en) | 1991-06-04 | 1991-06-04 | Method for producing boron / carbon composite neutron shielding material |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3132675A JP2633107B2 (en) | 1991-06-04 | 1991-06-04 | Method for producing boron / carbon composite neutron shielding material |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH04357497A JPH04357497A (en) | 1992-12-10 |
JP2633107B2 true JP2633107B2 (en) | 1997-07-23 |
Family
ID=15086878
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP3132675A Expired - Lifetime JP2633107B2 (en) | 1991-06-04 | 1991-06-04 | Method for producing boron / carbon composite neutron shielding material |
Country Status (1)
Country | Link |
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JP (1) | JP2633107B2 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2000171587A (en) * | 1998-12-04 | 2000-06-23 | Ishikawajima Harima Heavy Ind Co Ltd | Radiation shield |
-
1991
- 1991-06-04 JP JP3132675A patent/JP2633107B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
JPH04357497A (en) | 1992-12-10 |
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