Two models are currently taken as reference for the breeding blanket (BB) of DEMO, the Helium Cooled Pebble Bed (HCPB) and the Water Cooled Lithium Lead (WCLL). For both the models two Balance of Plant (BOP) configurations are currently investigated. They are all based on four independent primary heat transfer systems (PHTSs). The largest PHTS is devoted to remove the BB thermal power, two PHTSs for the divertor (DIV) and one for the vacuum vessel (VV) heat removals. Both DIV loops and VV loop transfer their thermal power directly to the power conversion system (PCS). The two BOP configurations are investigated to cope with the pulsed operation of the reactor. The first configuration consists of an “indirect coupling” of the BB PHTS to the PCS by an Intermediate Heat Transfer System placed in between them. The second configuration consists in a “direct-coupling” of the BB PHTS to the PCS.

Reliability, availability, maintainability and inspectability (RAMI) analyses for the four PHTS and PCS configurations are presented in this paper. The Failure Mode, Effect Analysis (FMEA) and the Reliability Block Diagram (RBD) methodologies have been used to perform the studies. As main result can be highlighted that even the low reliability of the systems to operate without failure and the large number of requests of corrective maintenance, all the systems are in compliance with an operational availability target of 30 %.

目前，DEMO的繁殖毯（BB）有两种模型作为参考，分别是氦冷卵石床（HCPB）和水冷锂铅（WCLL）。对于这两种模型，目前正在研究两种工厂平衡（BOP）配置。它们全部基于四个独立的主传热系统（PHTS）。最大的PHTS专门用于去除BB热能，两个PHTS用于分流器（DIV），一个用于真空容器（VV）的除热。DIV回路和VV回路都将其热功率直接传输到功率转换系统（PCS）。研究了两种防喷器配置，以应对反应堆的脉冲运行。第一种配置包括BB PHTS通过放置在它们之间的中间传热系统“间接耦合”到PCS。

本文介绍了四种PHTS和PCS配置的可靠性，可用性，可维护性和可检查性（RAMI）分析。失效模式，影响分析（FMEA）和可靠性框图（RBD）方法已用于进行研究。主要结果表明，即使系统无故障运行的可靠性很低，并且对纠正性维护的要求很高，所有系统都符合30％的可用性目标。