本文件为计算轻水反应堆非循环核燃料的衰变热功率提供了依据。为此，应考虑以下部件: -？核裂变产物的贡献； -？锕系元素的贡献； -？裂变产物中中子俘获产生的同位素的贡献。 本文件适用于装有由235和238铀组成的核燃料混合物的轻水反应堆（压水反应堆和沸水反应堆）。裂变产物对衰变热的贡献应用于其他热反应堆设计，包括重水反应堆，如果锕系元素和中子俘获的其他贡献是针对特定反应堆类型确定的，则是允许的。 不允许将其应用于回收的核燃料，如混合氧化物或再加工铀。 计算程序适用于0秒到10秒的衰变热周期。

This document provides the basis for calculating the decay heat power of non-recycled nuclear fuel of light water reactors. For this purpose the following components are considered: —？the contribution of the fission products from nuclear fission; —？the contribution of the actinides; —？the contribution of isotopes resulting from neutron capture in fission products. This document applies to light water reactors (pressurized water and boiling water reactors) loaded with a nuclear fuel mixture consisting of ²³⁵U and ²³⁸U. Application of the fission product contribution to decay heat developed using this document to other thermal reactor designs, including heavy water reactors, is permissible provided that the other contributions from actinides and neutron capture are determined for the specific reactor type. Its application to recycled nuclear fuel, like mixed-oxide or reprocessed uranium, is not permissible. The calculation procedures apply to decay heat periods from 0？s to 10⁹？s.