Document: NUREG-0800
Document ID: e6a79bdb-930d-4b57-91b9-39db4d8a76f1
Document Type: srp
Title: ENGINEERED SAFETY FEATURES MATERIALS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0631/ML063190010.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.1.1
CFR Part: 
CFR Title: 

Content:
ted with normal operation, maintenance, testing, and postulated accident conditions, including loss-of-coolant accidents, and to assure that the concentration of hydrogen in the containment atmosphere following postulated accidents is controlled to maintain containment integrity, hydrogen generation resulting from the corrosion of metals by containment sprays during a design-basis accident should be controlled as described in RG 1.7, position C.6. A. Pressurized Water Reactors (PWRs). To meet the requirements of GDC 4, 14, and 41, the composition of containment spray and core cooling water should be controlled to ensure a minimum pH of 7.0, as addressed in Branch Technical Position (BTP) 6-1, “pH for Emergency Coolant Water for PWRs.” Experience has shown that maintaining the pH of borated solutions at this level will help to inhibit initiation of stress corrosion cracking of austenitic stainless steel components. Hydrogen generation from the corrosion of materials within containment, such as aluminum and zinc, depends upon the corrosion rate, which in turn depends upon such factors as the coolant chemistry, the coolant pH, the metal and coolant temperature, and the surface area exposed to attack by the coolant. The assumed corrosion rates of materials in containment should be consistent with standard corrosion rate data. B. Boiling Water Reactors (BWRs). To meet the requirements of GDC 4, 14, and 41, the water used in the ESF systems should be controlled to provide assurance against stress corrosion cracking of unstabilized austenitic stainless steel components. Water used for emergency core cooling systems and spray systems should be controlled to ensure the following limits: Conductivity #0.5 mS/m (#5 μmhos/cm) @ 25 EC Chloride (Cl-) < 0.20 ppm pH = 5.3 to 8.6 @ 25 EC Hydrogen generation in BWR containments is assumed to follow the same characteristics as in pressurized water reactors (PWRs) in that the rates of hydrogen generation will rise with increasing