Abstract

The Versatile Test Reactor (VTR) is currently under development by the U.S. Department of Energy. It will provide very high fast neutron flux irradiation capabilities that are currently unavailable in the United States. Given the increasingly large number of advanced reactor concepts being pursued in recent years, this irradiation testing capability will be essential to support maturation of these designs. Radiation protection is an important part of the VTR design. High neutron fluxes can pose a challenge for radiation protection of the structures and equipment near the reactor core. This paper provides a summary on the status of the radiation protection considerations and shielding analysis performed for VTR under a nominal operating condition. The main radiation sources identified and examined in the study are applicable only under this operating condition. The paper focuses on three areas of radiation protection and shielding: secondary sodium activation in the intermediate heat exchanger, air activation in the reactor vessel auxiliary cooling system, and dose rate above the head access area due to primary sodium activation. VTR design and development are continuously progressing, and as such, the shielding considerations discussed in this paper will evolve alongside the overall VTR design.

摘要

美国能源部目前正在开发多功能试验反应堆（VTR）。它将提供目前在美国无法获得的非常高的快中子通量辐照能力。鉴于近年来越来越多的先进反应堆概念被追求，这种辐照测试能力对于支持这些设计的成熟至关重要。辐射防护是录像机设计的重要组成部分。高中子通量可能对反应堆堆芯附近的结构和设备的辐射防护构成挑战。本文概述了在标称操作条件下对 VTR 执行的辐射防护考虑和屏蔽分析的状态。研究中确定和检查的主要辐射源仅适用于这种操作条件。本文重点关注辐射防护和屏蔽的三个领域：中间换热器中的二次钠活化、反应堆容器辅助冷却系统中的空气活化以及由于一次钠活化而导致的头部接近区域上方的剂量率。VTR 的设计和开发在不断进步，因此，本文中讨论的屏蔽考虑因素将与整体 VTR 设计一起发展。