Document: NUREG-0800
Document ID: dcd79479-0633-4d67-ba17-e369513aa55d
Document Type: srp
Title: SPECTRUM4 OF ROD EJECTION ACCIDENTS (PWR)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350410.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.4.8
CFR Part: 
CFR Title: 

Content:
wer may use the results of previous case work, if the analytical methods have been previously reviewed and approved by the staff. Otherwise 15.4.8-2 Rev. 2 - July 1981 he must perform a de novo review on this case. Alternatively an audit of several calculations, using methods considered acceptable to the staff, may be done by the reviewer (or consultants to the staff). The primary concern oF the reviewer is how well the elements of the analytical model represent the true three-dimen- sional problem. Other items checked by the reviewer include feedback mechanisms, number of delayed neutron groups, two-dimen- sional representation of fuel element distribution, primary flow treatment, and scram input. f. Results of the calculations done by procedures described in steps a-e are expressed as values of the radially-averaged fuel rod enthalpy (in units of cal/gm). The reviewer determines that the maximum value does not exceed 280 cal/gm. 2. Verification of compliance with the second acceptance criterion is accomplished as follows: a. The same procedures considered in steps a-f above are followed. b. For each accident, the maximum primary system pressure should be calculated by an analytical method acceptable to the staff or, as before, an independent audit calculation is made by the staff. The reviewer checks the results (as obtained by the applicant or the staff) for compliance with the second criterion. 3. The number of fuel rods experiencing clad failure is determined (for use in evaluating the radiological consequences) by the following procedure: a. The reviewer determines that an acceptable procedure for calculating a departure from nucleate boiling condition during the reactivity excursion has been used. This may be done by referring to previous cases for the same nuclear steam supply system (NSSS) vendor. If no approved technique is available, as might be the case for the first project using a new or substantially revised model, the reviewer must perform a separate