Document: NUREG-0800
Document ID: 1734e678-943d-4e2c-a9a5-1e89a00a9865
Document Type: srp
Title: UNCONTROLLED CONTROL ROD ASSEMBLY WITHDRAWAL FROM A
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0636/ML063600413.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.4.1
CFR Part: 
CFR Title: 

Content:
asonably conservative and that specified acceptable fuel design limits will not be exceeded. For BWR/6 Designs 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 staff concludes that the requirements of General Design Criteria 10, 13, 17, 20, and 25 have been met. This conclusion is based on the following: 1. The applicant meets GDC 13 requirements by demonstrating that all credited instrumentation was available, and that actuations of protection systems, automatic and manual, occurred at values of monitored parameters that were within the instruments’ prescribed operating ranges. 2. The applicant has met the requirements 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 with and without offsite electrical power availability in accordance with the requirements of GDC 17. These requirements have been met since the system design contains a Rod Pattern Control System. This system has been reviewed and found acceptable because single failures in the reactor control system which could result in uncontrolled withdrawal of control rods under low-power conditions have been precluded. The scope of the review has included the design features, eighteen of which act to prevent such withdrawals. This review has shown that no single failure will permit an uncontrolled rod withdrawal that could lead to reactivity insertions greater than those routinely encountered during operation. For DC and COL reviews, the findings will also summarize the staff’s evaluation of requirements and restrictions (e.g., interface requirements and site