Modeling the Accumulators of the Advanced Neutron Source Reactor

An improved capability for modeling the transient behavior of the unique Advanced Neutron Source Reactor (ANSR) accumulator design has been developed. The ANSR accumulator behavior may now be simulated using an external model that is coupled to a RELAP5/MOD3 ANSR facility system model via a parallel virtual machine (PVM) connection. Existing RELAP5 code models were found to provide marginal results for simulating behavior of the unique ANSR accumulator design, and an improved accumulator modeling capability was desired. A new model for representing the ANSR accumulators, assessment and demonstration of that model, and the general methods by which external models may be coupled with RELAP5 system models using PVM connections are described.