Document: NRC Regulatory Guide
Document ID: d0bc0d48-8edb-492d-b813-53be9418b4aa
Document Type: regulatory_guide
Title: Maintenance of Water Purity in Boiling Water Reactors (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003740192.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.56
CFR Part: 
CFR Title: 

Content:
raliz ers, some contaminants, at very low concentrations, pass into the reactor vessel. Chloride ions and high or low pH conditions, which may promote stress corrosion cracking of austenitic stainless steel com ponents and structures, are of particular concern. To control contaminants within limiting condi tions, the conductivity of the coolant at the inlet.and outlet of the reactor water cleanup system should be continuously monitored. The chloride content and pH of the reactor water should be determined periodi cally. The reactor should not be operated for ex tended periods of time with the reactor water cleanup system out of service. Limits on chloride concentration and pH in the reactor vessel water of BWRs that have been found acceptable to the NRC staff are presented in the ap pendix to this guide. Also presented in the appendix are representative limits for the electrical conductiv ity of the water at several other locations in the BWR water cycle. C. REGULATORY POSITION Condensate demineralizers in boiling water reac tors should be designed and operated so as to permit an orderly shutdown of the reactor in case of serious leakage in the condenser or in other heat exchangers without contaminating the reactor coolant pressure boundary or core structural components with poten tially harmful constituents of the condenser cooling water. Sufficient instrumentation should be provided so that (1) the electrical conductivity of the conden sate is known, (2) the available capacity of the con d~nsate demineralizers can be determined at all times, and (3) the conductivity of the reactor coolant water at the inlet and outlet of each demineralizer is 1.56-2 known. Additional protection to the pressure vessel and core structural components should be provided in the form of a functioning reactor water cleanup sys tem and instrumentation to measure reactor water conductivity. An acceptable approach is as follows: 1. The licensee should establish appropriate limits for the