Document: NRC Regulatory Guide
Document ID: 74c49394-8dbf-46e7-b62a-b85de93b47d8
Document Type: regulatory_guide
Title: Initial Test Programs for Water-Cooled Nuclear Power Plants + HISTORY - HISTORY 11/2012 – DG-1259 , Proposed Revision 4 11/2006 – DG-1166 , Proposed Revision 3 (Rev. 4)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1229/ML12298A071.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.68
CFR Part: 
CFR Title: 

Content:
ns has been reached or invoked. C-3. Initial Criticality Procedures This section provides some specific guidance for the detailed procedure for operations associated with bringing the reactor critical for the first time. The guidance provided in Section 1, “Preoperational Test Procedures,” of this appendix is also considered applicable. The initial criticality procedure should include steps to ensure that the startup will proceed in a deliberate and orderly manner, changes in reactivity will be continuously monitored, and inverse multiplication plots will be maintained and interpreted. A critical rod position (boron concentration) should be predicted so that any anomalies may be noted and evaluated. All systems needed for startup should be aligned and in proper operation. The emergency liquid poison system should be operable and in readiness. Technical specification requirements must be met. Nuclear instruments should be calibrated. A neutron count rate (of at least 1/2 counts per second) should register on startup channels before the startup begins, and the signal to noise ratio should be known to be greater than 2. A conservative startup rate limit (no shorter than approximately a 30-second period) should be established. High flux scram trips should be set at their lowest value (approximately 5 percent to 20 percent). Implement containment closure procedures before changing plant modes that allow the reactor to start the approach to critical. Implement the radiation monitoring program to include operation of radiation barriers, airborne radiation monitors, air sampling, and baseline surveys before pulling control rods for the approach to critical. In accordance with TS requirements, all containment penetrations, the equipment hatch, and containment airlocks should be closed. Appendix C to DG-1259, Page C-8 C-4. Low-Power and Power-Ascension Procedures This section provides guidance for planning and preparing procedures for use in conducting the initial