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:
etion is reached. a. Recording conductivity meters should be in stalled at the inlet and outlet of both the condensate treatment system and reactor water cleanup system. The range of these instruments should be sufficient to measure all levels of potential water conductivity specified in the plant technical specifications. For the condensate treatment system, the conductivity meter readings should be calibrated so that estimates of condenser leakage can be made based on cooling water conductivity, condensate conductivity, and flow rate. The chemical composition of the cooling water and its relation to specific conductance should be established and periodically confirmed so that es timates of residual demineralizer capacity can be made. b. A recording flowmeter should be used to measure the rate of flow through each demineralizer. c. The quantity of the principal ion(s) likely to cause demineralizer breakthrough should be calcu lated by: (1) Converting the conductivity readings of the water entering the demineralizer to weight fraction (e.g., ppm or ppb) of the principal, ion(s) and (2) Integrating over time the product of con centration of this ion(s) and demineralizer flow. The input quantity of ion(s) to the demineralizers should be determined at a frequency adequate to en sure sufficient residual ion exchange capacity in the event of a major condenser leakage to prevent ex ceeding reactor coolant limits. d. Each demineralizer unit should be replaced or regenerated when the remaining capacity (calculated by subtracting the total utilization determined from conductivity and flow measurements in accordance with regulatory position 4.c from the initial capacity 1.56-3 determined in accordance with regulatory position 3) approaches the minimum residual demineralizer capacity determined in accordance with regulatory position 2. The accuracy of the above calculation should be checked by measurements made on resin samples taken when demineralizer units are removed from