Document: NUREG-0800
Document ID: 7abc5861-4ac1-4f27-ab53-f9997c382301
Document Type: srp
Title: SPECTRUM OF ROD EJECTION ACCIDENTS (PWR)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550014.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.4.8
CFR Part: 
CFR Title: 

Content:
ion(s). 15.4.8-5 Revision 3 - March 2007 D. The reviewer inspects the control rod insertion assumptions, which include trip parameters, trip delay time, rod velocity curve, and differential rod worth. Trip parameters and delay time are reviewed under SRP Section 7.2. Control rod worth is checked by the reviewer for consistency with the review under SRP Section 4.3. E. The applicant's analytical methods are reviewed. The reviewer may use the results of previous case work if the analytical methods have been reviewed and approved by the staff. Otherwise, he must do a de novo review. Alternatively, the reviewer may audit several calculations, using methods acceptable to the staff (or staff consultants). The reviewer’s primary concern is how well the elements of the analytical model represent the true three-dimensional problem. The reviewer also checks feedback mechanisms, number of delayed neutron groups, two-dimensional representation of fuel element distribution, primary flow treatment, and scram input. 2. For acceptance criterion II.2, the number of fuel rods with clad failure is determined (for use by SRP section 15.0.3 reviewer in evaluating radiological consequences of the rod ejection accident) by the following procedure: A. The reviewer determines whether an acceptable procedure for calculating a departure from nucleate boiling (DNB) condition during the reactivity excursion is used. This determination may be done by reference to previous cases for the same nuclear steam supply system vendor. If no approved technique is available (e.g., the first project using a new or substantially revised model), the reviewer must perform a separate detailed review which may be documented separately in a topical report. DNB must be calculated in accordance with the criteria reviewed and accepted under SRP Section 4.4. Typically, the criteria define a departure from nucleate boiling ratio (DNBR) less than 1.30 when NRC-approved CHF correlations are used. B. The reviewer must