ML19270F714
| ML19270F714 | |
| Person / Time | |
|---|---|
| Issue date: | 06/13/1978 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| References | |
| RTR-NUREG-75-087, RTR-NUREG-75-87 ETSB-11-4, NUDOCS 7903200096 | |
| Download: ML19270F714 (6) | |
Text
s Branch Technical Position, ETSB 11-4 Design Guidance For Radiological Effluent Monitoring Instrumentation Installed In Light-Water-Cocied Nuclear Power Reactors A.
Background
The primary design function of a radiological effluent monitor is the detectior, and measurement of radioactive materials released in gaseous or liquid effluent streams of light-water-cooled nuclear power reactors.
A second design function may bg that of generating a signal for the actbation of other systems which are capable of terminating or otherwise modifying the flow or nature of the effluent stream.
Examples of such systems are containment ventilation or purge isolation valves (PWR/BWR) and systems for diversion of building ventilation exhaust stre?ms from an untreated discharge path to an alternative treatment system such as a HEPA filter and charcoal adsorber system (BWR/PWR).
Depending on plant design characteristics and on site-specific meteorological uispersion parameters, the actuation of such systems as described above may be essential in mitigating the potential consequences of a design basis.
accident (DBA).
The need for such mitigating features is determined by calculating offsite doses resulting from the DBA.
The design and quality assurance criteria applied to the design, pro-curement, installation, testing, and operation of radiological effluent monito"s installed in light-water-cooled nuclear power reactors should provide assurance that the monitors will perform their design functions.
7903200096.
If the DBA analyses show that the actuation of engineered safety feature SF) systems is required to mitigate the consequences of a DBA, the ESF systems should be designed to appropriate ESF design criteria and should be subject -to ESF quality ~ assurance' criteria.
If a signal from a monitor is required for actuation of the ESF system,
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then that monitor should be designed and qualified to the design and.
quality assurance criteria applicable to the ESF system.
In other plant designs, monitors may be used to actuate systems to modify or tenninate releases from anticipated operational ocurrences to assure that offsite doses are maintained within limits specified in the plant Technical Specifications.
For these systems, the monitors should be designed and qualified to the design and quality assurance criteria applicable to the actuated system.
In some plant designs, a monitor may be required to provide a signal for the actuation of a ; ingle system which has a dual function:
(1) acting as an ESF system to mitigate the consequences of a DBA; and (2) to control releases from anticipated ov erational occurrences within the limits specified in the plant Technical Specifict Lions.
Examples of such systems are the standby gas treatment s ' stem of a BWR and containment purge isolation valve system of a PWR.
If the monitor is required to generate the actuation signal for both functions, or if it generates the actuation signal for the ESF function, then the design and quality assurance criteria applicable to the-monitor should be in accordance with the ESF criteria.
. A single system whose actuation serves this dual function may receive a signal for actuation of the non-ESF function (control or modification of effluent stream to meet the limits specified in the plant Technical
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Specifications) from a radiological effluent monitor and the s'ignal for the ESF function (accident mitigation) from another source, such as a pressu'r~e rise signal from the reactor protection system.
In this case the monitor should be designed and qualified to the criteria applicable to the non-ESF function.
A " system" of radiological effluent monitors for a single unit nuclear power reactor usually consists of five remote monitors connected by cable to a central console or cabinet where the data from each monitor is processed and recorded.
If one or more of the monitors measures a level of radioactivity greater than a predetermined limit, indicative of an accident condition, and it generates a signal for the actuation of an ESF system, then that monitor and all portions of the monitoring system which are active in generating the ESF actuation signal should be designed and qualified to the design and quality assurarce criteria for the ESF system.
In a given case, this might include the monitor, the electrical power to the monitor, the connecting cable and cable trays between the nionitor and a centrally located cabinet or console, the cabinet or console containing the cable termination, and instrumentation located within the cabinet or console.
. Components of the system which are not active in generating the ESF actuation signal, such as recorders and non-ESF channels, the failure of which will not affect the response capability of designated ESF channels, should be designed and qualified to criteria applica'ble to a non-ESF system.
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The design guidance set forth in this position paper provides reasonable assurance that monitors used to provide initiation signals for actuation of systems to control the release of radioactive materials in effluents are designed, constructed, installed, tested, and maintained on a level commensurate wi.th their intended function.
This position paper sets forth minimum branch requirements and is not intendea to prohibit the implementation of other equivalent design codes, standards, or quality assurance measures than those indicated hc ein.
B.
Definitions Radiological Effluent Monitor:
A device which removes a representative sample from the effluent stream, detects and quantitatively measures the radioactive meterials present in the sample, discharges the sampled medium back to the effluent stream, and transmits the measurement data to a central point.
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. Monitoring Systemi A system consisting of one or more remote monitors, a centrally located cabinet or console where data from the monitors is received, recorded, and displayed, and the necessary interconnecting cables,
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power supplies, pumps, motors, alarms, recorders, display panels, relays, and other auxiliary components.
C.
Branch Technical Position Design and quality assurance criteria for radiological effluent monitors should be consis' tent with the design and quality assurance criteria applicable to the systems which are F.ctuated by alann from the radiological effluent monitors.
Monitors actuating engineered safety feature (ESF) systems should be designed and qualified to the design and quality assurance criteria applicable to the ESF systems, as shown in Table 1.
Monitors actuating r.on-ESF systems should be designed and qualified to the design and quality assurance criteria applicable to the actuated system or to the criteria shown in Table I, below.
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TABLE I DESIG?! GUIDAtlCE FOR RADIOLOGICAL EFFLUEUT liO?lITORING It:5TRUMEilTATI0tl IllSTALLED Ill LIGHT UATEP. COOLED HUCLEAR PO' Category Design Criteria Quality Assurance Criteria
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s Group A-
' Review:
Reviewedunderl
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Standard Review Plan j
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7 Effluent Radiological j.3..
t' ltonitoring Instrumentation e
providing a signal to JReviewedby-Instrumeni initiate actuation of an j tation and Contr61 ESF system which is
? Systems Branch (ICSS) l Criteria:- Qual.ity capable of mitigating f
' Assurance criteria of the consequences of iCriteria:
Qualified to',Section 4 of IEEE Std. 279-a postulated accident.
jSeismic Category I per l1971 and requirements of
$and criteria set forth ( ppendix B to 10.CF I egulatory Guide-1.29, f A R
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]inIEEEStd 279-1971 i
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Group B Review:
Reviewed underl Review:
Reviewed under Standard Review Plan. ! Standard Review Plan 11.5 11.5 '
l Effluent Radiological Reviewed by:
Effluent fionitoring Instrumentation Reviewed by:
Effluent l Treatment Systems Branch.
providing a si.knal to Treatment Systems Branch (ETSB) initiate actda ion of a system required to (ETSB)
Criteria:
Quality Assur-reduce releases of radio-Manuf acture-ante criteria set forth in 4 active materials in Criteria:
effluents to' limits r's Standard per AtlSI Reg 61atoryI Guide :1.:143, specified in plant H13.10-1974.
Section.IV..
l Technical Specifications.
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!!ot required to initiate actuation for an ESF system.
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.=f VALUE-IMPACT ANALYSIS For Issue of Branch Technical Position ETSB 11-4 Design Guidance For Radiological Effluent Monitoring Instrumentation Installed In Light-Water-Cooled Nuclear Power Reactors 8
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