JPH0431080B2 - - Google Patents
Info
- Publication number
- JPH0431080B2 JPH0431080B2 JP1623285A JP1623285A JPH0431080B2 JP H0431080 B2 JPH0431080 B2 JP H0431080B2 JP 1623285 A JP1623285 A JP 1623285A JP 1623285 A JP1623285 A JP 1623285A JP H0431080 B2 JPH0431080 B2 JP H0431080B2
- Authority
- JP
- Japan
- Prior art keywords
- added
- silicone elastomer
- weight
- polypropylene
- neutron
- 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
Links
- -1 polypropylene Polymers 0.000 claims description 20
- 229920002379 silicone rubber Polymers 0.000 claims description 18
- 239000000463 material Substances 0.000 claims description 16
- 150000001639 boron compounds Chemical class 0.000 claims description 14
- 239000004743 Polypropylene Substances 0.000 claims description 10
- 229920001155 polypropylene Polymers 0.000 claims description 10
- 229910000048 titanium hydride Inorganic materials 0.000 claims description 10
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 7
- 230000007423 decrease Effects 0.000 description 4
- 238000001228 spectrum Methods 0.000 description 3
- 229910000975 Carbon steel Inorganic materials 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 239000010962 carbon steel Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 125000004429 atom Chemical group 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000004992 fission Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- JFALSRSLKYAFGM-OIOBTWANSA-N uranium-235 Chemical compound [235U] JFALSRSLKYAFGM-OIOBTWANSA-N 0.000 description 1
Description
（産業上の利用分野）
この発明はシリコーンエラストマーを基材とす
る中性子遮蔽性能に優れた中性子遮蔽材に関する
ものである。
（従来技術）
従来、原子炉等で使用される中性子遮蔽材とし
て、耐熱性、難燃性の優れた高分子であるシリコ
ーンエラストマーを基材とする遮蔽材が知られて
いる。例えば、特開昭54−1798号公報では、シリ
コーンエラストマーに対して熱中性子吸収のため
にホウ素化合物を添加したものが開示されてお
り、これはシリコーンエラストマー中にホウ素化
合物をいかに均一に分散させるかについての改良
であり、したがつてホウ素をいかに多量に添加さ
せるかに視点が置かれ、５〜75容量％（８〜85重
量％）のホウ素化合物を含有させるようにしてい
る。
ところでシリコーンエラストマーは元来水素含
有量が少ないため、ホウ素化合物の含有量が多い
と水素原子密度が小さくなつて中性子エネルギー
スペクトルの硬い（エネルギーの高い）場合、中
性子遮蔽性能が小さくなるという問題がある。
（発明の目的）
この発明はこのような従来の欠点を解消するた
めになされたものであり、シリコーンエラストマ
ーの特性を生かしつつ水素原子密度が低下しない
ようにした中性子遮蔽性能の優れた遮蔽材を提供
するものである。
（発明の構成）
この発明の第１の要旨は、シリコーンエラスト
マーにホウ素化合物が0.5〜５重量％添加されて
なるものである。また第２の要旨は、シリコーン
エラストマーにホウ素化合物が0.5〜５重量％添
加され、さらにポリプロピレンまたは水素化チタ
ンが添加されてなるものである。
（実施例）
シリコーンエラストマーは、含水素系高分子物
質の中では最も耐熱性および難燃性に優れた材料
の１つである。またシリコーンエラストマーは温
度硬化性があり、硬化前は液体状であるために、
その流動性を利用して複雑な形状の注型ができる
という利点がある。このような性質のシリコーン
エラストマーに対して、ホウ素化合物を加えると
熱中性子を吸収する能力を向上させることができ
る。このホウ素化合物としては、B4C、BN、
B2O3等があり、これらを粉末の状態で加えれば
よい。
上記ホウ素化合物の添加量は、遮蔽材が使用さ
れる場所の中性子エネルギースペクトルによつて
設定すればよい。ホウ素化合物の添加量とその効
果との関係を調べるために、ウラン235の核分裂
スペクトルを持つ中性子の線源を30cmの厚さの炭
素鋼の壁で遮蔽し、その状態での中性子線量率を
１とし、さらにこの炭素鋼の壁の外側を10cm厚さ
の遮蔽材で遮蔽した状態における中性子線量率を
計算した。なお、上記遮蔽材としてはシリコーン
エラストマーに対して添加するB4Cの割合を種々
変化させたところ、第１図曲線１に示すような結
果がえられた。すなわちB4Cの添加量が0.5〜５
重量％の範囲内では線量率は2.9以下と小さいの
に対し、５重量％を超えると急激に増加する。し
たがつて、B4Cの添加量は0.5〜５重量％の範囲
内に設定する必要がある。その他のホウ素化合物
の添加量についても同様と考えられる。
また上記遮蔽材にポリプロピレンまたは水素化
チタンを添加することによつて水素原子密度を増
加させることができる。例えば、上記遮蔽材の水
素原子密度が５×1022atoms／cm3の場合に、これ
をポリプロピレン30重量％、または水素化チタン
50重量％を添加すれば水素原子密度が６×
10atoms／cm3となつて、水素原子密度が20重量％
増加することになる。
上記添加量は、水素原子密度を向上させるため
には多いほどよいが、添加量が増加するとポリプ
ロピレンの場合は難燃性が低下し、水素化チタン
の場合は硬化前の流動性が低下する。したがつ
て、要求される遮蔽材の特性に応じて、添加量を
決定すればよく、またポリプロピレンと水素化チ
タンとの両者を適当な割合で添加してもよい。
第１表において、シリコーンエラストマーに対
してB4Cを種々の割合で加えた遮蔽材、さらにそ
れにポリプロピレンまたは水素化チタンを加えた
遮蔽材の線量率が減衰率を示す。同表において、
ＡはB4Cを8.2重量％加えた従来品、Ｂ〜Ｈはそ
れぞれ本願の実施例であつて、その他の添加物と
してＥはポリプロピレンを、Ｆ，Ｇ，Ｈはそれぞ
れ水素化チタンを加えている。
(Industrial Application Field) The present invention relates to a neutron shielding material having excellent neutron shielding performance and having a silicone elastomer as a base material. (Prior Art) Shielding materials based on silicone elastomer, which is a polymer with excellent heat resistance and flame retardance, have been known as neutron shielding materials used in nuclear reactors and the like. For example, JP-A-54-1798 discloses a silicone elastomer in which a boron compound is added for absorption of thermal neutrons. Therefore, the focus is on how much boron can be added, and the boron compound is contained in an amount of 5 to 75% by volume (8 to 85% by weight). By the way, silicone elastomers inherently have a low hydrogen content, so if the content of boron compounds is high, the hydrogen atom density will decrease, and if the neutron energy spectrum is hard (high energy), there is a problem that the neutron shielding performance will decrease. . (Purpose of the Invention) This invention was made in order to eliminate such conventional drawbacks, and it provides a shielding material with excellent neutron shielding performance that takes advantage of the characteristics of silicone elastomer and prevents the hydrogen atom density from decreasing. This is what we provide. (Structure of the Invention) The first aspect of the present invention is that 0.5 to 5% by weight of a boron compound is added to a silicone elastomer. The second feature is that 0.5 to 5% by weight of a boron compound is added to a silicone elastomer, and polypropylene or titanium hydride is further added. (Example) Silicone elastomer is one of the materials with the best heat resistance and flame retardancy among hydrogen-containing polymer substances. In addition, silicone elastomers are temperature-curable and are in a liquid state before curing.
It has the advantage of being able to be cast into complex shapes by utilizing its fluidity. Adding a boron compound to a silicone elastomer having such properties can improve its ability to absorb thermal neutrons. This boron compound includes B 4 C, BN,
There are B 2 O 3 , etc., and these can be added in the form of powder. The amount of the boron compound added may be determined depending on the neutron energy spectrum of the location where the shielding material is used. In order to investigate the relationship between the amount of boron compounds added and their effects, a neutron source with the fission spectrum of uranium-235 was shielded with a 30 cm thick carbon steel wall, and the neutron dose rate in that state was reduced to 1. Furthermore, we calculated the neutron dose rate when the outside of this carbon steel wall was shielded with a 10 cm thick shielding material. When the ratio of B 4 C added to the silicone elastomer was varied as the above-mentioned shielding material, results as shown in curve 1 in FIG. 1 were obtained. In other words, the amount of B 4 C added is 0.5 to 5
While the dose rate is small within the range of 2.9% by weight, it increases rapidly when it exceeds 5% by weight. Therefore, the amount of B 4 C added must be set within the range of 0.5 to 5% by weight. The same may be said of the amounts of other boron compounds added. Further, by adding polypropylene or titanium hydride to the above-mentioned shielding material, the hydrogen atom density can be increased. For example, if the hydrogen atom density of the above-mentioned shielding material is 5 x 10 22 atoms/cm 3 , it may be made of 30% by weight polypropylene or titanium hydride.
If 50% by weight is added, the hydrogen atom density increases to 6×
10atoms/ cm3 , hydrogen atom density is 20% by weight
will increase. The above addition amount is better as it increases in order to improve the hydrogen atom density, but when the addition amount increases, the flame retardance decreases in the case of polypropylene, and the fluidity before curing decreases in the case of titanium hydride. Therefore, the amount to be added may be determined depending on the required characteristics of the shielding material, and both polypropylene and titanium hydride may be added in an appropriate ratio. In Table 1, the dose rates of shielding materials in which B 4 C is added in various proportions to silicone elastomer, as well as shielding materials in which polypropylene or titanium hydride are added thereto, indicate the attenuation rate. In the same table,
A is a conventional product with 8.2% by weight of B 4 C added, B to H are examples of the present application, and other additives include E with polypropylene and F, G, and H with titanium hydride added respectively. There is.
【表】
同表から明らかなように、Ａの従来品では線量
率の減衰率は0.352であるのに対し、B4Cを0.5〜
５％の範囲で添加したＢ，Ｃ，Ｄでは0.355以上
となつており、さらにこれにポリプロピレンまた
は水素化チタンを添加したものでは0.386以上と
なつて、減衰率が向上していることがわかる。
（発明の効果）
以上説明したように、この発明はシリコーンエ
ラストマーにホウ素化合物が0.5〜５重量％添加
されてなるものであり、あるいはシリコーンエラ
ストマーにホウ素化合物が0.5〜５重量％添加さ
れ、さらにポリプロピレンまたは水素化チタンが
添加されてなるものであり、これによつてシリコ
ーンエラストマーの特性を生かしつつ、中性子遮
蔽性能の向上を達成したものである。[Table] As is clear from the table, the dose rate attenuation rate for the conventional product A is 0.352, while the attenuation rate for B 4 C is 0.5~
It can be seen that the attenuation rate is 0.355 or higher for B, C, and D added in a range of 5%, and that the attenuation rate is 0.386 or higher for those in which polypropylene or titanium hydride is added. (Effects of the Invention) As explained above, the present invention is made by adding 0.5 to 5% by weight of a boron compound to a silicone elastomer, or adding 0.5 to 5% by weight of a boron compound to a silicone elastomer, and further adding polypropylene to the silicone elastomer. Alternatively, titanium hydride is added, thereby achieving improved neutron shielding performance while taking advantage of the characteristics of silicone elastomer.
図面はB4Cの添加量と線量率との関係を示す特
性図である。
１……特性曲線。
The drawing is a characteristic diagram showing the relationship between the amount of B 4 C added and the dose rate. 1...Characteristic curve.
Claims (1)
0.5〜５重量％添加されてなる中性子遮蔽材。 ２ シリコーンエラストマーにホウ素化合物が
0.5〜５重量％添加され、さらにポリプロピレン
または水素化チタンが添加されてなる中性子遮蔽
材。[Claims] 1. Silicone elastomer contains a boron compound.
A neutron shielding material containing 0.5 to 5% by weight. 2 Boron compounds in silicone elastomer
A neutron shielding material containing 0.5 to 5% by weight of polypropylene or titanium hydride.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1623285A JPS61173198A (en) | 1985-01-29 | 1985-01-29 | Neutron shielding material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1623285A JPS61173198A (en) | 1985-01-29 | 1985-01-29 | Neutron shielding material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61173198A JPS61173198A (en) | 1986-08-04 |
| JPH0431080B2 true JPH0431080B2 (en) | 1992-05-25 |
Family
ID=11910805
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1623285A Granted JPS61173198A (en) | 1985-01-29 | 1985-01-29 | Neutron shielding material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61173198A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2833402B1 (en) * | 2001-12-12 | 2004-03-12 | Transnucleaire | NEUTRONIC SHIELDING AND SUB-CRITICITY MAINTAINING MATERIAL BASED ON VINYLESTER RESIN |
| JP5037011B2 (en) * | 2005-12-26 | 2012-09-26 | 株式会社リコー | Optical sensor device |
-
1985
- 1985-01-29 JP JP1623285A patent/JPS61173198A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61173198A (en) | 1986-08-04 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |