Document: NUREG-0800
Document ID: f813a982-efc9-4295-a0ff-eb6a289f39ba
Document Type: srp
Title: BOILING WATER REACTOR STABILITY
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550017.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.9
CFR Part: 
CFR Title: 

Content:
ity LTSs and facilitates meeting the requirements of GDC 20: A. The LTS should protect against SAFDL violations automatically. B. The LTS should demonstrate by analysis that either (i) the probability of instabilities in the allowed operating region is sufficiently small or (ii) unstable power oscillations can be detected and suppressed readily without SAFDL violations. The LTS may use a combination of both demonstrations for different instability modes. 15.9-5 March 2007 C. If the licensing basis option is declared inoperable the LTS should provide a backup option that may implement manual or administrative actions only if operator actions required to prevent SAFDLs can be accomplished within the two minutes allowed for operator action in the demonstration calculations. D. The LTS option should include generic technical specifications that address: i. The methodology for setpoint and region calculation and documentation of the setpoint on a cycle-specific basis (e.g., COLR). ii. Operability and surveillance requirements for the licensing basis option. iii. A time limit (120 days maximum) for operation under the backup option. 10. To meet requirements of GDC 13, stability-related instrumentation functionality should be demonstrated by analysis. Hardware implementation should follow SRP Section 7.2. 11. In addition to the density-wave instability modes, the applicant should ensure that the plant is free from other instability modes that could violate SAFDLs (e.g., startup or control system instabilities) or that oscillations can be detected and suppressed readily. Note: Some instability modes may be acceptable with no potential for SAFDL violation, (e.g., bi-stable flow or small-flow oscillations during low-pressure startup). Technical Rationale The technical rationale for application of these requirements to reviewing this SRP section is discussed in the following paragraphs: 1. GDC 12 states, “The reactor core and associated coolant, control, and protection