HWRR屏蔽层活化源项研究

Study on Source Term in Shielding Layer of HWRR

反应堆屏蔽层通常由钢筋混凝土浇筑而成,体积及重量巨大,是反应堆退役源项的重要来源之一。通过建立反应堆3D计算模型,利用MCNP和ORIGEN活化计算程序计算了重水研究堆(HWRR)屏蔽层不同位置的中子注量率和活化源项。为验证计算模型和计算结果的准确性,在HWRR屏蔽层活性区中央位置沿水平方向进行钻孔取样,对获得的混凝土样品中的60Co和152Eu的活度进行了测量,分析结果与计算结果较吻合,证明了理论计算模型的准确性。最后对HWRR屏蔽层的活化深度进行了计算,得出反应堆屏蔽层活化深度最大值为600 mm。计算结果证明保留外层屏蔽层的退役方案从理论上是可行的。

Reactor shielding layer is usually made of reinforced concrete,which is of great volume and weight,and is one of the important parts of reactor decommissioning source term.The neutron flux rate and activation source terms in different positions of the shielding layer of the Heavy Water Research Reactor(HWRR)were calculated by using MCNP and ORIGEN programs with establishing the reactor 3 D model.In order to verify the accuracy of the calculation model and the calculation results,a sample was obtained in the central area of the shielding layer of the HWRR,and the activity of 60Co and 152Eu in the samples was measured.The measurement results are in good agreement with the calculation results,which prove the accuracy of the theoretical calculation model.The activation depth of the shielding layer was calculated,and the results prove that the maximum activation depth of the shielding layer is about 600 mm.According to the calculation,it is proved that the decommissioning scheme of retaining the outer partial layer is theoretically feasible.