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:
e the changes with lines in the margin. boiling water reactors (BWRs) by maintaining ac ceptable purity levels in the reactor coolant. It further describes instrumentation acceptablejthe NRC staff for determining the condition of reactor coolant and coolant purification syste i S. B. DI Water quality ro s during construction when extensive e e n essary to ensure that components p e clean. Concern with proper ter n m start even before the plant operate• .. nti~e through all operations until finlshu aintenance of high water quality is nt ng all operations since water is often mra fn one part of the plant to another dur -ta s and this water can easily find its way to he ell and from there to the reactor. "Tn a typical BWR direct or single cycle reactor sys tem (see Fig. 1 in the appendix), water is boiled by means of a nuclear fission heat source. The steam and water mixture produced in the core area passes through steam separators where much of the water is removed. Wet steam passes from the separators to the steam dryers to produce relatively dry steam (less than 1/10 of a percent moisture). The steam at ap proximately 1000 psi and 550'F (288°C) enters the main steam lines and passes through the turbine to the main condenser. Condensed steam is collected in the hotwell located below the cooling tubes of the condenser. Leaks in the condenser tubes can result in circulating water entering the hotwell and introducing impurities. When the circulating water in the conden sers is seawater, the consequences of tube leaks may be quite significant; therefore, special precautions are required in seawater-cooled plants. De-aeration in the condenser reduces the oxygen content of the water. The condensate then passes USNRC REGULATORY GUIDES Comments should be sent to the Secretary of the Commission, US. Nuclear Regu Regulatory Guides are issued to describe and make available to the public methods latory Commission, Washington, D.C. 20555. Attention Docketing and Service