Document: NRC Regulatory Guide
Document ID: da2e0703-3488-44b0-b6d0-089aac7cae3d
Document Type: regulatory_guide
Title: Format and Content of Plant-Specific Pressurized Thermal Shock Safety Analysis Reports for Pressurized Water Reactors
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003740028.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.154
CFR Part: 
CFR Title: 

Content:
d be defined and i t s frequency noted. 4. THERMAL-HYDRAULIC ANALYSIS \[ This chapter is to present the reactor coolant pressures, temperatures, and heat transfer coefficients at the vessel's interior surface in the beltline region for the set of overcooling sequences that envelops the plant's potential for experiencing a PTS event. A good example is presented in Chapter 4 of Reference 3. Also the chapter is to present the details of the analysis methods used to obtain these fluid conditions and is to include the following sections: 1. The thermal-hydraul ic analysis plan and 1 ogic. 2. A description and evaluation of the thermal-hydraul ic models. 3. A description of any simplified analysis methods used in the study. 4. A description of the methods used to evaluate the effects of thermal stratification and mixing. 5 . Graphs of a1 1 the best-estimate thermal -hydraul ic results with their associated uncertainties and a detailed explanation of the transient behavior observed. Thermal-Hydraulic Analysis Plan This section should out1 ine the logic and identify the subtasks in the thermal-hydraul ic analysis. Subtasks incl ude detai led thermal- hydraul ic systems 1 analysis, simp1 ified thermal-hydraul ic systems analysis, and thermal stratifica- tion analysis. The logic should describe the sampling plan used to select sequences for detailed or simplified analysis. ORNL experience favors selecting detailed thermal-hydraulic analysis sequences, including at least a few severe examples of each type of postulated overcooling transient in order to understand and benchmark the plant behavior for subsequent simplified calculations. The order in which the scenarios are evaluated can result in a considerable reduc- tion in expenditures. By first analyzing the scenarios that are expected to be the bounding cases (i. e. , the most severe), calculations for an entire class of overcooling scenarios may be deemed unnecessary if the bounding case is not of PTS concern. Similarly,