GAS-PASS/H : a simulation code for gas reactor plant systems.
A simulation code for gas reactor plant systems has been developed. The code is intended for use in safety analysis and control studies for Generation-IV reactor concepts. We developed it anticipating an immediate application to direct cycle gas reactors. By programming in flexibility as to how components can be configured, we believe the code can be adapted for the indirect-cycle gas reactors relatively easy. The use of modular components and a general purpose equation solver allows for this. There are several capabilities that are included for investigating issues associated with direct cycle gas reactors. Issues include the safety characteristics of single shaft plants during coastdown and transition to shutdown heat removal following unprotected accidents, including depressurization, and the need for safety grade control systems. Basic components provided include turbine, compressor, recuperator, cooler, bypass valve, leak, accumulator, containment, and flow junction. The code permits a more rapid assessment of design concepts than is achievable using RELAP. RELAP requires detail beyond what is necessary at the design scoping stage. This increases the time to assemble an input deck and tends to make the code slower running. The core neutronics and decay heat models of GAS-PASS/H are taken from the liquid-metal version of MINISAS. The ex-reactor component models were developed from first principles. The network-based method for assembling component models into a system uses a general nonlinear solver to find the solution to the steady-state equations. The transient time-differenced equations are solved implicitly using the same solver. A direct cycle gas reactor is modeled and a loss of generator load transient is simulated for this reactor. While normally the reactor is scrammed, the plant safety case will require analysis of this event with failure of various safety systems. Therefore, we simulated the loss of load transient with a combined failure of the bypass valve to open and with the bypass valve open. The stability and the asymptotic state of the plant is of interest from the safety standpoint. GAS-PASS/H simulates the transient reasonably well. However, one can see that at a steady state the mechanical power delivered to the generator is less than 10 percent of the reactor power. This is less than the typical value of greater than 40 percent for a GTMHR. This result suggests that some work is needed to optimize the turbomachine efficiencies through better choice of turbomachine steady state reference operating points.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 943419
- Report Number(s):
- ANL/NE/CP-113708; TRN: US0900398
- Resource Relation:
- Conference: 2004 International Congress on Advances in Nuclear Power Plant (ICAPP '04); Jun. 13, 2004 - Jun. 17, 2004; Pittsburgh, PA
- Country of Publication:
- United States
- Language:
- ENGLISH
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