Document: NUREG-0800
Document ID: e459fbaa-1cf6-4054-a83a-500a6895feaf
Document Type: srp
Title: PROCESS AND EFFLUENT RADIOLOGICAL MONITORING INSTRUMENTATION AND
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350110.pdf
Revision Date: 2023-06
Chapter: 11
Section ID: 11.5
CFR Part: 
CFR Title: 

Content:
s, Structures, and Components Installed in Light-Water-Cooled Nuclear Power Plants." 11.5-13 Rev. 3 - July 1981 APPENDIX 11.5-A DESIGN GUIDANCE FOR RADIOLOGICAL EFFLUENT MONITORS PROVIDING SIGNALS FOR INITIATING TERMINATION OF FLOW OR OTHER MODIFICATION OF EFFLUENT STREAM PROPERTIES A. 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 that of providing a signal to automatically termi- nate or otherwise modify the effluent stream. Examples are the termination of exhaust air flow 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, such as a standby gas treatment system for a BWR plant. 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 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 due to anticipated operational occurrences to assure that offsite doses are maintained within the limits specified in the plant technical specifications. The design and quality assurance criteria applied to the design, procurement, installation, testing, and operation of radiological effluent monitors installed in light-water-cooled nuclear power reactors should provide assurance that the monitors will perform all of their design functions. If the DBA analysis noted above shows that the actuation of an engineered safety feature (ESF) system is required to mitigate the consequences of a DBA, and that a signal from a radiological