Document: NUREG-0800
Document ID: ef559b35-0671-46e4-b172-09155cca8b81
Document Type: srp
Title: SPECTRUM OF ROD DROP ACCIDENTS (BWR)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350427.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.4.9
CFR Part: 
CFR Title: 

Content:
n subsection II of this SRP (the reviewer may do an audit calculation when appropriate). 15.4.9-2 Rev. 2 - July 1981 3. The number of fuel rods experiencing clad failure and fuel melting is determined (for use in evaluating the radiological consequences) by the following procedures: a. The reviewer determines that the transient critical power ratio (CPR) has been computed by an acceptable technique (either pre- viously reviewed or reviewed de novo during this review) for analyses using full power conditions. b. The reviewer determines that the number of rods with enthalpy exceeding 170 cal/gm has been computed by an acceptable method. c. The reviewer determines that the amount of fuel exceeding melting conditions has been computed by an acceptable method. IV. EVALUATION FINDINGS The reviewer verifies that sufficient information has been provided and his review supports conclusions of the following type, to be included in the staff's safety evaluation report: The staff concludes that-the analysis of the rod drop accident is acceptable and meets the requirements of General Design Criterion 28. This conclusion is based on the following: The applicant met the requirements of GDC 28 with respect to preventing. postulated reactivity accidents that could result in damage to the reactor coolant pressure boundary greater than limited local yielding or cause sufficient damage that would significantly impair the capability to cool the core. The requirements have been met since the staff has evaluated the applicant's analysis of the assumed control rod drop accident and finds the assumptions, calculational techniques, and consequences acceptable. Since the calculations predict peak fuel enthalpies less than 280 cal/gm, prompt fuel rupture with consequent rapid heat transfer to the coolant from finely dispersed molted U02 was assumed not to occur. The pressure surge was, therefore, calculated on the basis of conventional heat transfer from the fuel and resulted in a pressure