ML19308B719

For Commentissue of Reg Guide 1.97, Instrumentation for Light-Water-Cooled Nuclear Power Plants to Assess Plant Conditions During & Following Accident

ML19308B719
Person / Time
Site:	Crane
Issue date:	12/31/1975
From:	NRC OFFICE OF STANDARDS DEVELOPMENT
To:
Shared Package
ML19308B699	List: ML19308B698 ML19308B714 ML19308B716 ML19308B718 ML19308B719 ML19308B722 ML19308B723 ML19308B724
References
TASK-TF, TASK-TMR REGGD-01.097, REGGD-1.097, NUDOCS 8001160788
Download: ML19308B719 (4)

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- APPENDIX-D

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' U.S. NUCLEAR REGULATORY COMMISSION.46.-?f.J4 _,. (.

December 1975

,,s, OFFICE OF STANDARDS DEVELOPMENT 1

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- REGULATORY GUIDE 1,297 1

a INSTRUMENTATION FOR LIGHT. WATER-CdOLED NUCLEAR POWER PLANTS TO ASSESS PLANT CONDITIONS DURING AND FOLLOWING AN ACCIDENT M.

A. INTRODUCTION possible situations that were not completely anticipated in the design of the plant;(2) to help predict the course Criterion 13. " Instrumentation and Control." of that an accident will take;(3) to d.. ermine whether the Appendix A " General Design Criteria for Nuclear Power reactor trip and engineered safety.fe ' systems are Plants." to 10 CFR Part 50. "Ucensing of Producti n functioning properly;(4) to determine ther the plant l

and Utilization Fad!ities," includes a requirement that is responding properly to the safety meMurs in opera-.

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instrumentatiort be provided to monitor variables and tion;(5) to allow for early irgtiin pf actIEd to protect systems for accident conditions as appropriate to ensure the public safety (if neccesary); (6 to furnish data needed to take manual aptioFif,(ah an)ingineered safety.

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adequate safety.

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feature malfunctions @) innanticipated conditions rec

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p CFR Part 50 includes a requirement that a control :oom 2' 1 esp 6Eding' effective 1 Criterio

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1 be provided from which actions can be taken to tioni(7) togrovideinformnon to the operator that wi!!" ' ~

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(c) the plant is not --..

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k maintain the nuclear power unit in a safe condition enable him..to deteTmine whether there has been d*J under accident conditions, including loss-of-coolant acci.

significant Tucl"d' Fsystem damage; and (8) to provide

~ k:.ta appropriate locations outside the control room be causciand consequences ef the event.

D I;g t'ents. Criterion 19 also requires that equipment at matelaf evidedce for post. accident investigation into the provided. Including instrumentation and controls to ( *v

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$4!wrys immediately determine what accident has -,

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maintain the ' unit in a safe condition during hot ft the start o s "#F4 shutdown.

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Criterion 64," Monitoring Radioactivity Releasei.".,,pf eccurred or is occurring and therefore cannot determin,e Appendix A to 10 CFR Part 50 includes a rEliiremerit/the appropriate response. For this reason, the reactor l

that means shall be provided for monitoring the reactor trip and certain safety actions (e.g.. emergency core _

containment atmosphere. space containing components co ling actuation, containment isolation. or depressuri.

for recirculation ofloss of-coolant accident fluids.efflu.

zation) are designed to be performed automatically I

ent discharge paths. and the plant environs for radio.

durirg the initial stages of an accident. Instrumentation activity that may be released from postolated accidents.

is also provided to indicate plant' parameters that are required to enable the operation of manually initiated P

'Ihis guide describes a rne'thod acceptable to the NRC safety related systems and other appropriate actions.

i staff for complying sith'the Commission's requirements to provide instrumentation to monitor plant uriables If normal power plant instrumentation remains func.

and systems duriag and following an accident in a tional for all accident conditions. it can provide indica.

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li;;ht water-cooled nuclear power plant.

tion, records, and (with certain types of instruments) q.s time history response for many parametersimportant to y7 following the course of the accident. Ilowever. since B. DISCUSSION

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4 some accidenu impose-severe operstmg requirements on e

l Monitored variables and systems should be used by instrumentation components, it may be necessary to the operator in accident surveillance (!) to help deter.

upgrade some instrumentation components to withstand j rnine the nature of an accident, with emphasis on more severe accident conditions and to measure a greater

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,te range of momtored variables than might normally be power systern should be displayed at all umes to the expested.

operator m the mam control room.

Examples of senous events that threaten safety are The effcetneness of containment atmosphere cleanup loss-of coolant accidents (LOCAsh anucipated tranuents systems m removmg airborne actinty from the contam-without seram ( ATWSst. reactmty excursions.~ and ment atmosphere should be monitored (i c.. measured).

radioactmty releases that iratiate s:entamment isolanon The temperature > and humidity of iodme traps should Such events require the operator to understand.~m a also be monitored to determme whether the traps are short time period, the state of readmess of enpucered overheating and thus potentia!!y in danger oflosing their safety features and their potential for bemg challenged radionuchde insentory or failmg to remove the radio-by an accident m progress. Instrumentauon provided for nuclides frorn the containment atmosphere.

this purpose should simphry the acudent assessment process and the determmation of the status oT eng.

The, required mstrumentation should be capable of

. neered safety features.

serviving the accident ennronment that it must momtor.

It therefore should either be designed to withstand the To determme the important variables and systems accident ennronment or be protected by a local.

whose salues or status should be displayed to the artificia! en ironment. If the ensironment surroundmg operator and therefore the momtonng mstrumentation an mstrument component is the same for acadent and that should be installed, a' study (Rei.1) was made of a normal operstmg conditions (e.g.. the mstrumentation range of postulated accidents. The study concluded that components m the mam control room). the instrumen-the following capabihties are most important to mam.

tation components need no special ennronmental capa-taining the integrity of the power plant after an bility.

accident: reactor shutdown. core cochng. contamment isolauon contamment pressure control, pnmary system The required mstrumentation should also be capable pressure control, and a heat transfer path from the core of functiomng after, but not necessanly dunng, a safe to a heat sink. These ntal capabilines are designed to shutdown earthquake.

preserve the integnty of the barners to radioactmty release (i.e., the fuel claddmg. primary coolant bound.

Instrumentation selected for accident monitoring ary. and containment).

should permit relatnely few deuces to proude the essential information needed by the operator to satisfy in selectinF parameters for accident surveillance.

the general objectives. %here practical. the same instru-attention should be pven to prouding mformatmn that ments should be used for normal and accident operation will aid the operator in achievmg and maintaining a safe to obtam the adsantage of normalinsernee surseillance.

shutdown condition, with emphasis on controlling reac.

Ilowever, the instruments should be specitically identi-tivity and estabbshing a heat transfer path from the core fied on control panels so that the operator can easily to the heat sink. Particular attention should be given to determme that they are mtended for use under accident, parameters that indicate that the barners to radioaeunty as well as normal. conditions.

release are being challenggd and that pubhc safety may be m jeopardy. Thus, instrumentauon that shows the C. REGULATORY POSITION absence or presence of ugmficant fuel damage or metal water reaction is of special importance.

1. For each postulated accident that threatens public safety (for example, a LOCA or ATWS event. reactivity Information concerning the integnty of the primary excur* on. or radioactivity release that initiates contam-coolant boundary and the containment is also of utal ment ts)lation). the applicant should perform detailed interest For example, the character of a postulated safety analyses to determme (a) the parameters to be LOCA dunng the first two or three mmutes of the measured and (b) the mstrument ranfes, responses. and accident can best be determmed by momtonng the accuracies required to proside the operator with the reactor coolant pressure transient. An analog recorder information necessary to assess the nature of the with a response and senuunty consist nt with the accident, the course the aci.Jent will take. the response anticipated pressure transient would be the type of of the safety features, the potential for breselung the instrument needed for tlus purpose. Comparable records barners to radioactivity release, the need for manual of the pressure transients and temperature gradient in action, and the operatingstatus of significant equipment the containment could also be very useful.

during and followmg the accident. The guidehnes m References I and 2 should be used to make such Because both short and long term operational effec-analyses along with the Fuidehnes in Reference 3 tiveness of the emergency core co21mg system (ECCS) deahng with morutoringinside the power plant.

are important, sufficient informauon concerning the ICCS status should be prouded to permit post. accident.

2. Tlie essential instrumentation required by the surveillance. Sinularly. the status of the emergency operator to diagnose and monitor significant accident D-2 S

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conditions should be speciGed for each system required

7. To the extent practical, accident monitonng in-to be operable dunng and after the accident. A strum-cution mputs should be from sensors that tabulation of such mstrumentation should be provided.

directly measure the desired vanables, along with a documented justification to show that the instrumentation is adequate to pronde the operator with

8. To the extent practical, the same indicators should the necessary mformation: The table should include the be used for accident momtonng as are used in the instruments major operational parameters and indicate normal operations of the plant.

the manner m which the instrument outputs wdl be recorded.

9. The accident momtonng instrumentation should be speciGcally identided on control panels so that the

3. The accident monitoring instrumentation compo-operator can easily discem that they are intended for use nents. and modules should be of a quahty that is under accident conditions. The displays should be consistent with min mum rnanntenance requ rements and arranged to simphfy the operator's surveillance. mterpre-i i

low fadure rates. Oaahty levels should be achieved tation. and response determmation following an accident through the speettication of requtrements known to signal.

promote high quality.

10. Anf equipment that is used for both accident

4. The axident monitonng instrumentation should momtonng and controi functions should be classitied as be designed with sufficient margm to mamtam necessary part of aeddent monitonng instrumentation. The trans-

- functional capability under estreme conomons (as appli-rmssion o signals from accident momtormg equipment cable) relating to nnronment. energy supply. malfune-for control system use should be through isolation tions, and seeident. The instrumentation should either devices that are classiGed as part of the accident-be quahtied to surdve the appropnate operstmg conda.

monitormg instrumentation and that meet all recom-tions or be suitably protected from the ennronment.'Its mendations of this document.

qualifiestions should be in accordance with Regulatory Guide 1.89. "Qualifiestion of Class IE Equipment for

11. $ leans should be provided for checking. with a Nuclear Power Plants." and it should contmue to high degree of conridence, the operational asadabdity of function within the.equired accuracy subsequent to.

each input sensor dunng resetor operation. This may be but not necessanly dunng. a safe shutdown carthquake.

secomphshed m sarious ways;for example:

5. The accident momtonng instrumentation should

a. By perturbmg the monitored vanable; be designed with redundant channels so that a smg!e failure does not present the operator from determinmg

b. By introducing and sarymg. as appropnate, a the nature of an accident, the functiomng of the substitute input to the sensor of the same nature engmeered safety features, the need for operator action.

as the measured vanable;cr' and the response of the plant to the safety measures m operation. One channel of each redundant set of

c. By cross. checking between channels that bear a channels should be recorded and energized from the known relationship to each other and that have station Class I E instrumentatmn s.c. system.

readouts avadable.

NOTE: " Single fadure" includes such events as the

12. Capability should be provided for servicing, shorting or open-circuitmg of interconnectmg signal or testmg. and cahbratmg the accident momtonng instru.

power cables. It also includes single credible malfune-mentation. For those parts of the instrumentation where tions or esents that cause a number of consequential the required interval between testing will be less than the component, module, or channel fadures. For example.

nermal tm.e mierval between generstmg stauon shut-the ' overheatmg of an amphtier module would be a downs. 2 eapabihty for testmg durmg power operanon "smgle radure" even though sescrat transist it radures should be prouded. serwmg. testmg. and ealibration might result. Nicehanical damage to a mode switch programs should be specified to ensure proper perfor.

would be a " single fadure" although seseral channels mance at all t mes.

' might become mvolved.

13. ihe design should permit administrative control

6. Channels that provide signals for redundant chan.

of the means for manually bypassmg channels.

nels should be independent and physiea!!y separated to accomphsh decourhng of the etieets of unufe ennron-I 4. The deugn should permit aditumstratne control mental faetors, eteetne tranuents. and phy9 eat accident of the access to all setromt adjustments, module con >equences documented m the deugn basis and to eahbration adjtstments.and test pomis.

reduce the likelihood of mteracuans between channels dunng mamtenance operations or in the event of

15. The accident monitonng instrumentation should channel malfunction.

be designed to proside the operator with securate.

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complete, and timely information regardmg its own REFERENCES status. The daign should nummise the development of conditions that would cause meters, annunciators, recorders, alarms, etc., to pse anomalous indications

1. Battelle<olumbus Laboratones."Momtoring Post-confusir.g to the operator.

Accident Conditions m Power Reactors," Bhll.X.647

^ I' *

16. The instrumentation should be designed to facih-tate the recognition. location. replacement, repair or adjustment of malfunctionmg components or modules.

2 U.S. Nuclear Regulatory Commission. " Standard Format and Content of Safety Analysis Reports far D. IMPLEMENTATION Nuclear Power Plants.' NUREG-75/094. Replatory Guide t.70. Rev. 2. Sept.1975.

The purpose of this section is to provide information to applicants and licensees regarding the NRC stafi's plans for te.ing this reFulatory guide.

3. BNW1-1635. " Technological Considerations in Except in those cases in which the applicant proposes Emergency Instrumentation Preparedness," May 1972.

an acceptable alternative method for complying with specified portions of the Commission's regulations. this d

guide will be used by the staff in evaluatmg all Copies of the above documents are available from the construction permit applications submitted after August National Technical Information Senice, Spnngfield, Va.

1,1976.

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