Document: NUREG-0800
Document ID: 66e7af3b-21c0-444f-8737-0830bb176eba
Document Type: srp
Title: PROCESS AND EFFLUENT RADIOLOGICAL MONITORING INSTRUMENTATION
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1502/ML15029A182.pdf
Revision Date: 2023-06
Chapter: 11
Section ID: 11.5
CFR Part: 
CFR Title: 

Content:
monitored, sampled, or analyzed (as indicated) prior to release. 11.5-60 Revision 6 – January 2016 APPENDIX 11.5-A DESIGN GUIDANCE FOR RADIOLOGICAL EFFLUENT MONITORS PROVIDING SIGNALS FOR INITIATING TERMINATION OF FLOW OR OTHER MODIFICATION OF EFFLUENT STREAM PROPERTIES 1. Background The primary design function of a radiological effluent monitor is the detection and measurement of radioactive materials released in gaseous or liquid effluent streams of light- water-cooled nuclear power reactors. An additional design function of some monitors is to provide a signal to automatically terminate or otherwise modify the effluent stream. Examples of this function are the termination of exhaust airflow by closure of containment ventilation or purge isolation valves and diversion of building ventilation exhaust streams from an untreated discharge path to an alternative treatment system using high-efficiency particulate air and charcoal filters. Depending on plant design and onsite meteorology, such an action may be necessary to mitigate the consequences of a design-basis accident (DBA). The need for such mitigation is determined by calculating the offsite doses that would result from the DBA. In other plant designs, radiological effluent monitors are used to actuate systems to modify or terminate releases for other purposes (e.g., to terminate releases from AOOs occurrences to ensure that offsite doses are maintained within the limits specified in the plant TS and RETS or SREC and ODCM. The design and QA criteria applied to the design, procurement, installation, testing, and operation of radiological effluent monitors installed in light-water-cooled nuclear power reactors should provide reasonable assurance that the monitors will perform all of their design safety functions using the guidance of SRP Chapter 7, SRP BTP 7-10, SRP Chapter 13, and RG 1.97 for safety-related systems and RG 1.143, and industry guidance for nonsafety-related systems. If the DBA analysis indicates