Study on the burn-up characteristics of a thermal neutron filter containing BC particles for NTD-Si irradiation

NTDシリコン照射のためのBC粒子を用いた熱中性子フィルターの燃焼特性に関する研究

米田 政夫   ; 小原 徹*

Komeda, Masao; Obara, Toru*

無数のBC粒子から構成される熱中性子フィルターの燃焼特性について明らかにした。熱中性子フィルターの燃焼に伴う透過中性子数変化の評価方法について検討を行い、その評価方法の適用範囲について熱中性子フィルター試験片を用いた実験により明らかにした。さらに熱中性子フィルターで用いるBC粒子の粒径及び濃度の評価方法を明らかにした。

We have investigated an alternative irradiation method for silicon doping using a thermal neutron filter to increase the irradiation efficiency in the Japan Research Reactor No. 3 (JRR-3). Because of the restrictions caused by engineering design and radioactivity, aluminum mixed BC particles was adopted as a filter material. The burn-up characteristics of a thermal neutron filter containing a zillion BC particles were described. A method for evaluating neutron transmissivity as boron burning in the neutron filter was developed. The applicable scope of the method via experiments using thermal neutron filters was clarified. A method by which we could calculate the suitable diameter and density of BC particles was derived.