Document: NUREG-0800
Document ID: 7c5a6f62-3fbc-4bde-8062-2eb15eeb6d45
Document Type: srp
Title: UNCONTROLLED CONTROL ROD. ASSEMBLY WITHDRAWAL FROM A SUBCRITICAL OR LOW POWER
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350326.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.4.1
CFR Part: 
CFR Title: 

Content:
lysis should be presented and should include maximum power levels reached for the reactor and the peak fuel rod, reactor temperatures and pressures, maximum heat flux levels, and the related fuel duty (operating conditions and performance). The latter are compared with the acceptance criteria in subsection II of this SRP. IV. EVALUATION FINDINGS If the staff, on completion of the review finds the applicant's analysis accept- able, conclusions of the following type should be included in the staff's safety evaluation report: The possibilities for single failures of the reactor control system which could result in uncontrolled withdrawal of control rods under low power startup conditions have been reviewed. The scope of the review has included investigations of initial conditions and control rod reactivity worths, the course of the resulting transients or steady-state conditions, and the instrument response to the transient or power maldistribution. The methods used to determine the peak fuel rod response, and the input into that analysis, such as power distributions and reactivity feedback effects due to moderator and fuel temperature changes, have been examined. (If audit calculations have been done, they should be summarized.) The staff concludes that the requirements of General Design Criteria 10, 20, and 25 have been met. This conclusion is based on the following: 15.4.1-3 Rev. 2 - July 1981 The applicant has met the requirement of GDC 10 that the specified acceptable fuel design limits are not exceeded, GDC 20 that the reactivity control systems are automatically initiated so that specified acceptable fuel design limits are not exceeded, and GDC 25 that single malfunctions in the reactivity control system will not cause the specified acceptable fuel design limits to be exceeded. These require- ments have been met by comparing the resulting extreme operating conditions and response for the fuel (i.e., fuel duty) with the acceptance criteria for fuel damage (e.g.,