Document: NRC Regulatory Guide
Document ID: 6f0a99f2-d25a-44e3-b7f2-3286449a9752
Document Type: regulatory_guide
Title: Water Sources for Long-Term Recirculation Cooling Following a Loss-of-Coolant Accident (Rev. 5)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2126/ML21266A185.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.82
CFR Part: 
CFR Title: 

Content:
staff review guidance (Ref. 13) provides a general approach to plant-specific head loss testing. This guidance document discusses the staff positions on various aspects of head loss testing, including scaling of the plant strainer to the test strainer module, considerations for debris transport and debris accumulation on the strainer during testing, surrogate debris similitude requirements, and posttest data processing extrapolation. 1.3.12.2 The objective of prototypical head loss testing is to determine the potential peak or bounding head loss that could occur across a suction strainer debris bed during a postulated LOCA scenario. If the test facility is scaled properly and the testing procedures and inputs are conservative, the measured head loss is also expected to be conservative. To ensure adequate strainer function, licensees should design the test facility properly and follow conservative procedures for testing. The conditions within the test tank should be prototypical or conservative with respect to the plant, including the postulated debris loading, the recirculation system hydraulics, and key aspects of various accident scenarios. The primary scaling parameters are the screen area, the dimensions of the strainer elements (e.g., disks), the submergence level, the number of strainer elements, the debris amounts, and the local fluid flow conditions, as applicable. These parameters affect the flow velocities approaching the test strainer and the velocities through accumulated debris. DG-1385, Page 31 1.3.12.3 The test specifications should be designed to determine a reasonably bounding head loss from all possible types of debris beds that could accumulate on the strainer, considering the plant-specific debris quantities transported from various break scenarios. In some cases, more than one scenario will need to be modeled during a plant test program. This may be necessary if a plant has various debris types that are not uniformly distributed throughout