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Title: Preliminary design report for SCDAP/RELAP5 lower core plate model

Technical Report ·
DOI:https://doi.org/10.2172/663261· OSTI ID:663261
 [1];  [2]
  1. Lockheed Martin Idaho Technologies Co., Idaho Falls, ID (United States). Idaho National Engineering and Environmental Lab.
  2. Oak Ridge National Lab., TN (United States)

The SCDAP/RELAP5 computer code is a best-estimate analysis tool for performing nuclear reactor severe accident simulations. Under primary sponsorship of the US Nuclear Regulatory Commission (NRC), Idaho National Engineering and Environmental Laboratory (INEEL) is responsible for overall maintenance of this code and for improvements for pressurized water reactor (PWR) applications. Since 1991, Oak Ridge National Laboratory (ORNL) has been improving SCDAP/RELAP5 for boiling water reactor (BWR) applications. The RELAP5 portion of the code performs the thermal-hydraulic calculations for both normal and severe accident conditions. The structures within the reactor vessel and coolant system can be represented with either RELAP5 heat structures or SCDAP/RELAP5 severe accident structures. The RELAP5 heat structures are limited to normal operating conditions (i.e., no structural oxidation, melting, or relocation), while the SCDAP portion of the code is capable of representing structural degradation and core damage progression that can occur under severe accident conditions. DCDAP/RELAP5 currently assumes that molten material which leaves the core region falls into the lower vessel head without interaction with structural materials. The objective of this design report is to describe the modifications required for SCDAP/RELAP5 to treat the thermal response of the structures in the core plate region as molten material relocates downward from the core, through the core plate region, and into the lower plenum. This has been a joint task between INEEL and ORNL, with INEEL focusing on PWR-specific design, and ORNL focusing upon the BWR-specific aspects. Chapter 2 describes the structures in the core plate region that must be represented by the proposed model. Chapter 3 presents the available information about the damage progression that is anticipated to occur in the core plate region during a severe accident, including typical SCDAP/RELAP5 simulation results. Chapter 4 provides a description of the implementation of the recommended model and Chapter 5 discusses the testing which could be done to verify the design and implementation of the model.

Research Organization:
Lockheed Martin Idaho Technologies Co., Idaho National Engineering and Environmental Lab., Idaho Falls, ID (United States)
Sponsoring Organization:
USDOE Office of Environmental Restoration and Waste Management, Washington, DC (United States)
DOE Contract Number:
AC07-94ID13223
OSTI ID:
663261
Report Number(s):
INEEL/EXT-98-00702; ON: DE98058446; TRN: 99:000413
Resource Relation:
Other Information: PBD: Jul 1998
Country of Publication:
United States
Language:
English