ML20066F988

Proposed Tech Spec Table 3.3.7.10-1, Radioactive Gaseous Effluent Monitoring Instrumentation

ML20066F988
Person / Time
Site:	Nine Mile Point
Issue date:	01/21/1991
From:	NIAGARA MOHAWK POWER CORP.
To:
Shared Package
ML20066F978	List: ML20066F976 ML20066F983 ML20066F988
References
NUDOCS 9101240308
Download: ML20066F988 (11)

Text

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ATTACHMENT A-NIAGARA MOHAWK POWER CORPORATION-

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LICENSE NO. NPF-69 DOCKET NO.'50-410-Proposed Changes to the Technical Sptgifications' ]'

. Replace existing pages-3/4 3-98', 99, 100,-101, and 102 1. .a-tihe-attached revised pages. These pages have marginal markings;to indicate the change to;theltext. -j t

1 000449GG5 9101240308 DR 910121

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i" 3 1 iTABLE-. 3;3.7.10-1 y

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JRADI0 ACTIVE GASEOUS EFFLUENT-MONITORING INSTRUMENTATION:

i MINIMUM . - - . .

CHANNELS: APPLICA-- _

ACTION' O INSTRUMENT- . OPERABLE 'BILITY--

1. Offgas System j

a. Noble Gas Activity Monitor.-1 -

Providing Alarm and Automatic -

Termination of' Release -2 1351

b. System Flow-Rate-Measuring Device ~ - 136- ,

c. Sample Flow-Rate Measuring Device :2 136e

2. Offgas System Explosive Gas Monitoring- ]

Sys tem" -

a. Hydrogen Monttor Train-A 1: 137 (Instrument 20FG-AT-16A or 7 20FG-AT_- 115) .

b. Hydrogen Monitor Train.'B-  : 137 1 (Instrument.20FG-AT-16B or_.

4 20FG-AT-115) .;

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- 3. Radwaste/ Reactor Building Vent Effluent) ,

System i 4'

a Noble Gas Activity Monitorti fl . tt 139

b. Iodine-Sampler .lc tt; 138'

c. Particulate. Sampler ;1< t t --

138

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d. Flow-Rate Monitoi :1: 'tt , 136!

e. Sample Flow-Rate-Monitor 1- tt -.

1136-

4. Main Stack Effluent: i f

? a. Noble Gas Activity'Monitort'- <1 ft" 139- l

.b. Iodine-Sampler 1 .

tt 138 j>

c. Particulate _ Sampler '

tt. 138J j

d. Flow-Rate Monitor-- 1- ~tt. 136 11

e. Sample Flow-Rate Monitor 1_ ' tt: 136-- g; l

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j NINE' MILE.~ POINT -l UNIT 2 1 3/5 3-98: i

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' RADIOACTIVE GASEOUS EFFLUENT- HONITORING INSTRUMENTAT80N' TABLE: NOTATIONS i

• - During offgas system %. *lon.

.Only one train l required to b6 in operation..-

t. Includes high range' noble gas _ monitoring capability.

t tt At all times. l ACTIONS  :

s ACTION 135 - a. W1th-thr 'mber.of:0PERABLE channels'one less than required by1 4 the.Mir T .1 Channels CPERABLE requirement,'effluenttreleases via:. :j this pathway may continuesprovided the inoperable-channel is 1

-placed in.the/ tripped condition-withincl2 hours.  ;

b.- Hith the number-of'.0PERABLE ciannels two.less than'. required by- f the Minimum Channels OPERABLE _ requirement, effluentereleases via: 1 this pathway may continue-provided. grab samples are taken at- 4 least_once per--12-hours-andithese samples are analyzednfor: gross

. activity within 24: hours.- ,

ACTION 136 - Hith the number ofi channelsc0PERABLE-less than-required by the  ;

' Minimum. Channels OPERABLE requirement,? effluent releases vlaithis  !

pathway may continue provided the_ flow rate for'the inoperable ~ q channel (s) is estimatediat leastionce per 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.-

ACTION 137 - With the number.of channels' 0PERABLE .less than required by. the Minimum Channels OPERABLE _ requirement,qoperation of,the.offgas system:- t may continue-provided grab samples are collected'at least once per 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />!and analyzed _within the:foilowing 4-hours.

q ACTION 138 - With the number of. channels 0PERABLE less than required by the' .  ;

Minimum' Channels OPERABLE requirement, effluent releases via this pathway may continue provided-samples areJcontinuously collected; j starting within 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />sLof-discovery, using1 auxiliary sampling .l equipment as required in TableL4.ll'.2-1.

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4 ACTION 139-- a. With the number of channels' 0PER/BLE less inan required oy the

. Minimum Channels 0PERABLE require sent,' effluent releases lVia?this _.

pathway may continue provided:grao samples are- taken at ileast  ?

once per 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />s-and-theseisamples are analyzed for gross ___ _. ,

activity within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />'for a radioactivity-limit of detection of at least-1 x'.10" microc # 3/ml.

b. Restore the inoperabi'e channel (s) to OPERABLELstatus'within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or-in . lieu _of another re.w c required by Specification 6.9.1, prepare-and submit.a Sg cial Report to:the Commission-  ;

pursuant;-to-Specification 6.9.2 within_-14 days followingDthe  ;

event outlining the action!tarsen; the cause of the inoperability and the' schedule for restoring the system to 0PERABLE status.

UNINE. MILE POINT.- UNIT 2 3/4'3-99

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TABLE-4.3.7.10-1

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- RADIOACTIVE GASEOUS EFFLUENT HONITORING INSTRUMENTATION SURVEILLANCE REQUIREMENTS- ^- :j s2 r>> - - +

_ x- .

.. CHANNEL- MODES IN HHICH'

^ p CHANNEL - SOURCE CHANNEL FUNCTIONAL ... SURVEILLANCE -

r" , INSTRUMENT CHECK CHECK- ~ CALIBRATION . TEST REQUIRED j -

. T g l.- ' -1. Offgas. System .

I L a. . Nobis Gas' Activity Monitor -. **

D NA R(a.e) M(b.c) 'l ., i il 1 - Providing' Alarm ~and-Automatic '

, y --Termination"of Release 1 m .

.b. System Flow-Rate Measuri.ng Device.- .D - NA R' . Q.  !

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[. c. -Sample Flow-Rate Measuring Device.. NA- ,R  :. Q --

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. 2. Offgas System Explosive' Gas '

it Moriitoring L System - - .

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2 a'. .. Hydrogen Monitor Train ~A- D NAl  : Q(d) sM

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' Hydrogen Monitor Train D -D - NA- -'Q(d)

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3. .

Radwaste/ Reactor Building Vent'-

Effluent System. <

- 'a. .. Noble,sas Activity 1 Monitor.it 'D} :M R(a)

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. Iodine Sampler :NA'

-* ~b'. H2  : NA: NA-

.c; ' ParticulSte Samplei H - NA: ' NA . N A ---

I- -d. Flow-Rate' Monitor-. JD ~NA. R '

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- e' . Sample Elow-Rate Monitor' D .. . NA[ 3 R .Q . .. .

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TABLE 4.3.7.10-1 (Continued) 3 RA_DI0 ACTIVE GASEOUS EFFLUENT MONITORING INSTRUMENTATION SURVEILLANCE REQUIREMENTS r5 y CHANNEL MODES IN HHICH C CHANNEL SOURCE CHANNEL FUNCTIONAL SURVEILLANCE E INSTRUMENT CHECK CHECK CALIBRATION TEST ' REQUIRED

14. Main Stack Ef t iuer;t g

i a. Hoble Gas Activity Monitort D M R(a) QCc)

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t Iodifie Sampler Particulate Sampler H

H NA NA NA NA NA NA

d. Flow-Rate Monitor D NA R Q

e. Sample Flow-Rate Monitor D NA R Q l Y

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ITABLE 4 . 3 . 7 .-1 0 -11 (Continued)-

RADI0 ACTIVE GASEOUS EFFLUENT MONITORING- I INSTRUMENTATION SURVEILLANCE REQUIREMENTS..

TABLE' NOTATIONS

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At all times.

-- l Dur.ing-offgas: system operation. l H

t Includes.high range noble gas monitoring capability. .!

1 (a) The initial-: CHANNEL CALIB_ RATION shall be. performed using=one or more of the reference standards certified by-the National-Bureau of Standardsi(NBS) or using:standhrds that-have been obtained from a

-suppliers that' participate in measurement-assurance activities with  !'

NBS, or using actual samples of gaseous? effluents:that have been-

-analyzed on a system that has been calibrated:with NBS: traceable- >

sources. These standards shall; permit calibrating theisystem over its intended range of energy'and' measurement.. For subsequent' CHANNEL CALIBRATION,{ sources that have beenirelated to the: initial calibration may be used.

(b)- The CHANNEL FUNCTIONAL-TEST shallialso demonstrate:the: automatic i isolation capability of,this pathway.and-that: control;: room alarm annunciation occurs if the-instrument indicates' measured levels above 1 the Alarm / Trip 1Setpoint (Each channel willLbe tested independently;so j as'to not initiate isolation during-operation)..

(c) 'The CHANNEL _ FUNCTIONAL TEST)shallcalso demonstrate-that control room 1

-alarm annunciation occurs if any oftthe.following conditions exists: "

(1) -Instrument-indicates measured levels.above the alarm setpoint J (2) Circuit failure.

(3) : Instrument indicates a downscale failure.

(4) Instrument controls :not set in operate modei (d) The CHANNEL CALIBRATION'shall include'the.'use ofLstandard gasJsamples containi'ng a nominal:

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-(1) One-volume percent-hydrogen, baiance nitrogen, and (2)- Four volume percent: hydrogen, t:. lance nitrogen.

(e) The CHANNEL' CALIBRATION shalliaiso-demonstrate that automatic t +

isolation of this pathway occurs when the_ instrument channels indicate, measured levels above?the Trip Setpoint.- u NINE' MILE POINT - UNIT 2- 3/4 3-102

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. ATTACHMENT ~B1 , ,

' NIAGARA MQHAWK POWER [ CORPORATION, LICENSE <NO.-NPF-691

DOCKET.NO. 504410- ,

c 3.upportino Information and-No'Sionificant Basards References,

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1) " Technical Specifications!- Enhancing:the: Safety Impact?"

NUREG-1024, November 1983; q

In t roduc tiorl The Nine Mile Point'Unitf2GTechnica14 specifications, specificallyJ -

sItem 1.a .on. Table E4!. 3,.7.10-0, ? require.Disolation of-: the 'of fgas -;

system as part of;the monthlyEfunctiona17testiofithe-offgas?

rystem noble gascactivity monitors.; ' Isolation:of the:Loffgas( .  :

system while the,plantiisfoperating!createsithe-=possibilityLoft loss ofi condenser' vacuum-and anlassociateduturbinestrip..fTesting)  ;

of thegisolation function---in thisTmannerebaniresult::.in j undesirable challengeszto plant' shutdown;systemsR The proposed 1  ;

! -changes replace the requirement?to--isolate-theloffgas'systemLwith L a requirementLtorverify:theLisolationicapabilityjof,the:

, individual noble gas monitor channels'. In' addition,-TableL. >

L 3.3.7.10-1_ is being proposed fortrevisiontto more accurately reflect the design of the nobleOgashmonitor41nstrumentation.;

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Discussion Theloffgas' system noble oe; activity monitoring-instrumentation; i

~-is;part of the RadioactiveiGaseous Effluent: Monitoring! .

.-Instrumentation -system. The coble:; gas 1 activity mo'nitoring:-system ,

consists of two of f -line gaseot.1: monitors,120FG-CAB-13A and 13B, c j '

ar ranged -in 'two-out-of-two l'ogic. f The 1 monitors: isolate the'.

offgas:systemiupon sensing highiradiation i~nithe'offgas .

pretreatment. inlet line--by closing 120FG-AOV-103.- Both monitors ,

must-detect radiationElevelsfabove?theitrip!setpoint;in order for- 1 the..offgas system to. isolate.: :The setpoint ifor. the monitors -

corresponds to--a = predetermined < releasenrate dete ainedHin accordanceowith'10 CFR 20:and is documented.in"the Offeite Dose -

Calculation 1 Manual'(ODCM). .The two-out-of-two' logic is. utilized 2000449GG6 3

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d to preclude spurious isolations and resultant turbine trips. -The-monitors are discussed in-Sections 11.3.2.1 and 11.5.2.1.3,-en r Pages 11.2-6 and 11.5-10 respectively, of the-Unit 2 Updated i i

Safety Analysis' Report.(USAR). The monitors are depicted schematically in USAR Figure 11.5-2 and their location in the offgas system is shown on USAR Figure 11.3-lb. Valve 20FG-AOV~

103 is shown on USAR Figure 11.3-ic. Technical Specification Table 4.3.7.10-1 currently. requires-a monthly functional test of the offgas monitors (See Item 1.a of-the-table). . Note (b) of Table-4.3.7.10-1' states the functional test shall also.

demonstrate that automatic isolation of the-effluent pathway occurs. Isolation of the offgas_ system, if it is not: restored to operation within a matter of minutes,-will result in a1 turbine I trip and associated reactor scram due to a loss of vacuum. The proposed change would add note (e) to Table 4.3.7.10-1 to; require 4 verification of actual valve closure as partHof the refueling frequency channel calibration. Note-(b) has been revised to require thet the monthly functional test verify that each individual channel trips upon_ sensing-a high radiation condition.

Nuclear Regulatory Commission' findings related to identified problems in testing-intervals in Technical Specifications l -(Reference 1) concluded that frequent testing of certain components can potentially lead to. undesirable challenges to-

plant shutdown systems. : There is a strong Lincentive - to mini'mize i

instrumentation testing in order to reduce the total-time.the plant is vulnerable-to. unnecessary-challenges to plant shutdown  ;

systems. As stated-above, isolating the offgas-system on.a monthly basis incurs the risk of a reactor scram. Plant scrame, or the potential for plant _ scrams, have a detrimental-effect on plant safety in terms of core damage frequency. Revising the requirements such that the isolation capability of the_ system is verified when the plant is shutdown for refueling results;in a net increase in plant safety _-since it_ eliminates the challenges to shutdown systems' associated'with the potential reactor scrams.

While the. decrease in the testing frequency of the' isolation valve may result in an incremental decrease in the overall reliability of the isolation system,-the isolation function of l the offgac monitors is not directly-related to plant safety. The oftgas monitors provide monitoring capability in_accordance with 10 CFR 20 and terminate releases to prevent exceeding release limits determined in the ODCM. The indirect impact on-plant safety is fu;ther illustrated by the fact that the Technical F Specifications permit alternate grab campling;upon loss of the monitors ar4d not a plant shutdown. Therefore, the decrease in the relietil.ity of the isolation system is more than offset by.

the increase in plant safety due to the elimination of challenges l to shutdown systems.

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V As stated above, there are two gaseous monitors in a two-out-of-two configuration. Each monitor has a separate flow meter that monitors the flr;w-rate of the sample stream. These sample flow-rate measuring devices: alarm at a central control panel upon sensing sample flow outside the required range. The sample flow-rate measuring devices are identified as Item 1.c on Technical '

Specification Tables 3.3.7.10-1 and 4.3.7.10-1. Table 3.3.7.10-  ;

1 specifies 1 as the Minimum Channels operable requirement for  ;

both the Noble Gas Activity Monitors (Item 1.a) and their associated Samp30 flow-Rate Measuring Devices (Item 1.c). Since-there are two of each, and the Noble Gas Activity Monitors are arranged in a two-out-of-two logic,'the correct number of Mit:'.aum Required Operable Channels for both Item 1.a and 1.c is 2. Table 3.3.7.10-1 is being proposed for revision to reflect this. .

i The Actions ascociated with inct-rable channels require revision os a result of changes to the number of Required Operable Channels. In addition, the numbering of Actions 135 and 136 has been reversed to maintain numerical' sequence. This numbering change was also made elsewhere on Table 3.3.7.10-1 to assure consistency. Proposed Action 135 (formerly Action 136) has been  ;

revised to allow continued' effluent release, without grab sampling, with one noble-gas activity monitor channel inoperable and in the tripped condition. Placing one channel in a two-out-of-two logic system-in the tripped condition increases the I overail reliability of the logic system. Action 135 has also i

been revised to allow continued effluent release with two  ;

l inoperable noble gas activity monitors provided grab sampling is 1

performed every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. This is consistent with the previous ,

I requirement for a one channel system.

Proposed Action 136 (formerly 135).has been. revised to allow continued efflusnt release with an inoperable sample flow-rate measuring device provided the flow rate for the inoperable channel (s) is estimated at least.once per four hours. This is consistent with the previous requirement for a one channel system. The change to Action 136 does not alter the required actions for the other monitors in the Specification. It-is understood that the requirements of Action 13i are only applicable for noble gas activity monitors which are operable in accordance with the requirements of Table 3.3.7.10-1. Finally, an editorici change is proposed to Tables 3.3.7.10-1 and 4.3.7.10-1. " Sampler Flow-R6te" in Items 1.c, 3.e, and 4.e should read as " Sample Flow-Rate" to provide consistency w3th design documentation.

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Conclusion The proposed changes result in a net overall increase in plant safety due to the reduction in potential challenges to plant shutdown systems. The capability of the Radioactive Gaseous Effluent Monitoring System remains intact and provides adequate assurance that the limits of 10 CFR 20 will be maintained.

10 CFR 50.91 requires that at the time a licensee requests an amendment, it must provide to the Commission its analysis using_

the standards in 10 CFR-50.92 concerning the issue of no significant hazards consideration. Therefore, in accordance with 10 CFR 50.91, the following analysis has been performed:

The operatior. af Nine Mile Point Ucit 2, in accordance with the proposed amenuaent, will not involve a significant increase in the probability or consequences of an accident previously evaluated.

The design of the offgas system and the associated process gaseous monitors has 3.ot changed. The existing operability requirements for the noble ges monitors will remain intact. The capability of the monitors themselves and their associated instrumentation will still be verified on a monthly basis.

Verifying automatic isolat:on on a refueling cycle frequency provides adequate assurance of the operability of the isclation valve and assures that overall system performance remains at an acceptable leval. With one monitor in the trip condition, the-remaining operable monitor provides a level of protection equivalent to or greater than that provided with both monitors operable. With both monitors inoperable, grab sampling on a twelve-hour interval provides assurance that noble gas releases in excess of predetermined levels will not go undetected.

Also, revising the operability and surveillance requirements has no effect on the probability of an accident since a gaseous monitor does not initiate an accident. In addition, the editorial changes provide consistency and do not alter the intent or interpretation of the Specification. Therefore, operation of Nine Mile Point Unit 2, in accordance with the proposed amendment, will not involve a significant increase in the i

probability or consequences of an accident previously cvaluated.

l The operation of Nine Mile Point Unit 2, in accordance with the l proposed amendment, will not create the possibility of a new or-l different kind of accident from any accident previously i evaluated.

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The design of the offgas system and the associated process gaseous monitors has not changed. The existing operability requirements for the noble gas-monitors will remain intact. The editecial changes do not alter the intent of the Specification.

Thur, the proposed change will not alter the plant configuration or any mode of operation. Therefore, operation of Nine Mile  :

Point Unit 2, in accordance with the proposed amendmsnt, will not j create the possibility of a new or different kind of accident q from any accident previously evaluated.

The operation of Nine Mils Point Unit 2, in accordance with the proposed amendment, will not involve a significant reduction in a f margin of safety.

The proposed change revises the surveillance requirements for .Te l offgas process gaseous monitors to minimize challenges to plant shutdown systems and corrects the prescribed number of Minimum Channels operable for the gaseouz monitors and their associated 3 sample flow-rate device. The change will not affect the reliability or performance of the gasecus monitors. The changes involve only the surveillance requirements and do not alter the ,

current Limiting condition for Operation or the intent of accompanying Action Statements for the Gaseous Effluent Monitoring System. The proposed surveillance requirements provide adequate assurance that the. Gaseous Effluent Monitoring l Syster will .naintain radioactive releases within the prescribed l limits of 10 CFR 20. Finally, the proposed editorial changes i

provide consistency and do not alter the intent or interpretation Therefore, operation of Nine Mile Point of the Specifications.

, Unit 2, in accordance with the proposed amendment, will not involve a significant reduction in a margin of safety.

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