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:
ar 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 detailed review (which may be documented separately in a topical report). b. The reviewer must determine that the number of rods used in the radiological evaluation is the number of rods calculated to have a departure from nucleate boiling. Departure from nucleate boiling must be calculated in accordance with the criteria reviewed and accepted under SRP Section 4.4. Typically, the criterion defines a departure from nucleate boiling ratio (DNBR) less than 1.30 when DNB correlations such as W-3 (Ref. 4) or BAW-2 (Ref. 5) are used. 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 ejection accidents is acceptable and meets the requirements of General Design Criterion 28. This conclusion is based on the following: 15.4.8-3 Rev. 2 - July 1981 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 by demonstrating that the regulatory positions of Regulatory Guide 1.77, "Assumptions Used for Evaluating a Control Rod Ejection Accident for PWR's" are complied with. The staff has evaluated the applicant's analysis of the assumed control rod ejection accident and finds the assumptions, calculation techniques, and consequences acceptable. Since the calculations resulted in peak fuel enthalpies less than 280 cal/gm, prompt fuel rupture with consequent rapid heat transfer to the coolant from finely dispersed