ML20155G634

Informs of Approval of Documents Re Station Blackout, W/Exceptions.Requests That Generic Response Document Be Revised.Satement Re Unavailability of HVAC in Licensee Response Necessary

ML20155G634
Person / Time
Issue date:	10/07/1988
From:	Thadani A Office of Nuclear Reactor Regulation
To:	Rasin W NUCLEAR ENERGY INSTITUTE (FORMERLY NUCLEAR MGMT &
References
TAC-40577, NUDOCS 8810170275
Download: ML20155G634 (17)

Text

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October 7,1938 .

Mr. William H. Rasin Nuclear Management and Resources Council 1776 Eye St. N.W. i Suite 300 Washington, D.C. 20006-2496

SUBJECT:

APPROVAL OF NUMARC 0000MENTS ON STATION BLACK 0UT (TAC 40577)

By letter to T.E. Murley (NRC) dated September 28, 1988, you submitted six final documents for staff approval. These documents have been discussed between NUMARC personnel and the staff in one or more of the working .neetings that took place on July 28, September 15 and Septeriber 22,1988 (suninaries of these treetings are dated August 15, September 12 and October 3,1988, respectively).

The technical staff has reviewed these six documents, and conclude that the final versions that you submitted on Se mber 28, 1988, reflect agreements trade in the three working meetings stat above. However, it is noted that on one particular issue, agreerrent was not required; NUMARC and the staff agreed to disagree. This issue involves the identification in the "Generic Response to Station Blackout Rule for Plants Using Alternate AC Power" of the unavailat'ility of HVAC in specific areas of concern including the control roce corrplex, it is our view that the explicit statement of this unavailability of HVAC in the licensee response is necessary to facilitate and assure the effectiveness of our review process, and of the subsequent audits of supporting documentation that may be required to e;'1blish full conformance to 10 CFR '

50.63. Therefore, we request that this generic response document be revised as indicated below.

With the exceptions noted, these docunents are approved as follows: '

1 & 2. "Genet ic Response to Station Blackout Rule for Plants Using Alternate KC' P'cVeP'"a n d*GFnFrli F RFs)FniF roTtst'isn' Bl FckFuTRWe"fo'r' Pl a n t'; i

_U, sing, A,C,,In_ dependent StFt'ioF WaHFu't'R'el)[o[niF PFw'e'r C'"""~""~

These two docurrents provide acceptable fomats for a licensee to i provide its plant-specific response in accordance with 10 CFR 50.63(C).

However, pages 6, 7, 10 and 12 of the generic response for plants using alternate AC power should be revised as shown on the enclosed marked-up pages. With these revisions, these documents define the amount and depth of infomation needed by the staff; additional infotration ny be requested of a licensee if needed to detemine whether a licensee has achieved full confotrance with 10 CFR 50.63, i

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fir, Rasin 3. _",Re,sponses to luestions Raised at the Ste' f on Bla_ckout Seminars" This document serves as appropriate clarif cation to the existing acceptable guidance for addressing the station blackout issue. This document should be revised as indicated on the enclosed marked-up pages.

4 & 5. "Guidelines and Technical Bases for NUMARC Initiatives Addressing e'n' dexta'n'd YtstToh'B%Eoiit"afITghFMitiiTeiciFrF:~"Ap"p'YistEis

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Addressing t

Yt'aYisn~M FcWu't','a t].[ijghlt[K, ale rl,)](aftJ,r's)[77p',e'nifjQY,oyi c aTR,ep,o r,t" These documents provide an acceptable n:eans of addressing equipment operability in a station blacko'2t; they can be viewed as providing clarification of, and replacing, the existing Appendix F founti in NUMARC 87-00. Therefore, the reference to Appendix F in Regulatory Guide 1.155 now refers to these documents. Appendix F should be revised as indicated on the enclosed marked-up pages.

6. "Errata to NUMARC_87 00" This docunient is accepted as providing corrections, including those indicated on the enclosed marked-up pages, to NUMARC 87-00.

Copies of the above documents may be distributed to participating licensees.

Sincerely, OrfOlitcd S/ M by M Ned tJ for ,

Ash [dC.Thada1,AssistantDire or '

for Systems i Division of Engineering and Systems  !

Technology 1 Office of fiuclear Reactor Regulation '

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Enclosure ENCLOSURE TO LETTER, A. THADANI TO W. RASIN, DATED OCTOBER 7,1938.

The following marked-up pages are included:

Document Page Generic Response, 6 Alternate AC Power 7 10 12 Questions and Answers 13 16 21 37 52 Errata 8 (with NUMARC 87-00 pages 2-12 and 2-13 attached)

Appendix F F-3 F-8 i

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GENERIC RESPONSE TO STATION BLACKOUT RULE YOR PLANTS USING ALTERNATE AC POWER decay heat removal for (insert required coping duration category frca NUMARC 87-00, Section 3.2.5) hours. LIST SOURCES AND NUMBER OF GALIANS PROVIDED BY EACH SOURCE.

SELECT ONE OF THE FOLLOWING TWO SENTENCES AND INSERT HERE:

a. No plant nodifications or procedure changes are

[ ' needed to utilize these water sources; or h b. The following plant modifications and/or procedure changes are necessary to utilize these water 4

• sources. LIST MODIFICATIONS (S) WITH A BRIEF DESCRIPTION.

(D 2. Effects of Loss of Ventilation (Section */.2.4)

SELECT ONE OF THE FOLLOWING TWO PARAGRAPHS.

- T g The AAC power source provide, power to HVAC systems

, serving dominant areas of concern. Therefore, the effects of loss of ventilation were not assessed; or 4

\k HVAC systems serving the following dominant areas of concerm@are (list the dominant areas of not available: Reasonable assurance of the operability of

, concert .

~ station blackout response equipment in the above area (s)

. has been assessed using Appendix F to NUMARC 87-00.

Q *- NOTE: IF THE REQUIRED COPING DURATION CATEGORY IS LESS TRAN EIGHT IiOURS, NUMARC 87-00 TOPICAL REPORT MAY ALSO

{ BE USED.

. .  % SELECT ONE OF THE FOLicWING TWO PARAGRAPHS.

i No modifications and/or procedures are required to provide reasonable assurance for equipment operability; or ,

.i The following nodifications and/or prochdures are

.G y. required to provide reasonable asstrance of equipment operability. LIST AND BRIEFLY DESCRIBE.

3. Reactor Coolant Inventerv (Section 2.51 SELECT ONE OF THE FOLLOWING THREE PARAGRAPHS:

The AAC source powers the necessary'make-up systems to maintain adequate reactor coolant system inventory to

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GENERIC RESPONSE TO STATION BLACKOUT RULE FOR PLANTS USING ALTERNATE AC POWBR ensure that the core is cooled for the required coping duration; or The ability to maintain adequate reactor coolant system l inventory to ensure that the core is cooled has been assessed for (insert required coping durationThe category).

generic SELECT ONE OF THE FOLLOWING TWO SENTENCES.

analyses listed in Section 2.5.2 of NUMARC 87-00 were used for this assessment and are applicable to the specific design of (insert plant name); or, A clant- )

specific analysis was used for this assessment. Note: l THE GENERIC NSSS VENDOR ANALYSES REFERENCED IN SECTION J 2.5 DO NOT APPLY FOR A SBO BEYOND FOUR HOURS. OTHER NSSS VENDOR ANALYSES OR PLANT-SPECIFIC ANALYSES MAY NEED TO BE REVIEWED IF THE RIQUIRED COPING DURATION CATEGORY EXCEEDS FOUR l LOURS. The expected rates of reactor coolant inventory loss under SBO conditions do not result in core uncovery (for a PWR) or more than a momentary core uncovery (for a BWR) in a SBO of (insert required coping duration category) .Therefore, makeup systems in addition to those currently available under SBO conditions are not required to maintain core cooling under natural circulation (including reflux boiling); or The ability to maintain adequate reactor coolant system inventory to ensure that core is cooled has been evaluated for the required SBO duration. It has been determined that the expected rates of reactor coolant inventory loss under SBO conditions result in core uncovery (for a PWR) or more than a momentary core uncovery (for a BWR) in the specified SBO duration. The following modifications and associated procedure changes are required to ensure that appropriate reactor coolant makeup water can be provided under SBO conditions. LIST AND BRIEFLY DESCRIBE.

COMPLETE THE FOLI4 WING SECTIONS IF THE AAC POWER IS NOT AVAILABLE WITHIN TEN MINUTES OF THE ONSET OF STATION BLACKOUT Condensate Inventory For Decay Heat Renova 1[Section X 1.

- 7.2.11)

SELECT ONE OF THE FOLI4 WING TWO PARAGRAPHS:

It has been determined from section 7.2.1 of NUMARC 87-00 that [ insert number) gallons of water are required for decay heat removal for (insert required coping duration category from NUMARC 87-00, Section 3.2.5).

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' GENERIC RESPONSE TO STATION BLACK 0DT RULE FOR PLANTS USING ALTERNATE AC POWER ABEA TEMPERATURE HPCI/HPCS Room (insert value)

RCIC Room (insert value)

Main Steam Tunnel (insert value)

c. Control Room complex for PWR's or BWR's The assumption in NUPARC 87-00, Sact on 2.7.1 that o-thecontrolroomwillnotexceed120{Fduringa station blackout has been assessed.

SELECT ONE OF THE FOLI4 WING TWO PARAGRAPHS.

The controg room at [ insert plant name) does not exceed 120 F during a station blackout. Therefore, the control room is not a dominant area of concern; or The control room at [ insert plant name) has been l calculated to reach a steady stgte ambient air temperature of (insert value) F during a station i blackout. Therefore, the control room is a  !

a dominant area of concern. i

? i SELECT ONE OF THE FOLI4 WING TWO PARAGRAPHS.

Reasonable assurance of the operability of station blackout response equipment in the above dominant area (s) of concern has been assessed using Appendix F to -

NUMARC 87-00 and No modifications or/or the Topical associated Report. are procedures required to provide or reasonable assurance for equipment operability;

• Reasonable assurance of the operability of station blackout response equipment in the above dominant area (s) has been assessed usinl 2Appendix F to NUMARC 87-00 and/or the Topical Report. The following modifications and/or associated procedure changes are required to provide reasonable assurance for equipment operability:

} LIST AND BRIEFLY DESCRIBE.

5. Containrent Isolation fSection 7.2.5) i SELECT ONE OF THE FOLI4 WING TWopAGRAPHS1 g

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" ', GENERIC RESPONSE TO STATION BLACKOUT RULE FOR PLANTS USING ALTERNATE AC PCWER systems in addition to thor,e currently available under SBO conditions are not required to maintain core cooling under natural circulation (including reflux boiling); or The ability to maintain adequate reactor coolant system inventory to ensure that core is cooled has been evaluated for the required SBO duration. It has been determined that the expected rates of reactor coolant inventory loss under SBO conditions result in core uncovery (for a PWR) or more than a momentary core uncovery (for a BRR) in the specified SBO duration. The following modifications and associated procedure changes are required to ensure that appropriate reactor coolant makeup water can be provided under SBO conditions. LIST AND BRIELY r DESCRIBE.

The modifications and associated procedure changes identified in ai Qs B and C above will be completed (insert time) after the notification provided by the Director, Office of Huclaar Reactor Regulation in accordance with 10 C.F.R. 50. 63 (c) (3) .

Very truly yours, company Official cc: NUMARC l

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3.2.2 EAC Power Conficuration

24. Q: Define emergency AC.

1 A: Emergency AC is your s' andby AC power supplies as l

defined in NUMARC 87 JO to meet GDC-17. '

25. Q: If a site has tv , units, both 1 out of 2 EDG configuration is there any argument for going to 2 FOG '.6NFt'Gv A AT70'Y cut of 4 ,a* that site?

7 SOO A: The T out of 43 configuration is for diesels which are norna11v shared between the units. If the diesels are not normally shared, there is no basis for using the 2 out of 4 configuration. .

26. Q: When determining the number of necessary EAC standby power supplies, what load requirements should be considered?

l A: As described in NUMARC 87-00, Section 3.2.2 part 2.B, the safe shutdown loads associated with loss of I offsite AC power are the minimum loads which should be considered when determining the number of necessary EAC s6urces. These loads do not necessarily include LOCA loads.

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A: Current actual reliabilities are determined per Section 3.2.3 and these in turn are used to determine TAMET' the EDG g, reliability in section 3.2.4 and these target reliabilities are used in part to determine the required station blackout coping duration. Once the '

coping duration, with target reliabilities, is

(

established then utilities will maintain these reliabilities through a program discussed in Appendix -

D of the NUMARC 87-00 document. This program is currently under further devalopment by NUMARC as resolution to Generic Issue B-56. De, tailed criteria ,

- W4 for maintaining performance to sustaingt he target re11 abilities will be part of the EDG Reliability Program.

33. Q: What happens if a plant uses .975 reliability in i order to get itself into the 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> category, then later falls below this level?

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A: Target reliabilities should be meintained through a maintenance program which may be comprised of the I elements found in NUMARC 87-00, Appendix D. I The process of maintaining the target reliabilities will be detailed in the EDG Reliabi'lity Program developed

, as resolution to Generic Issue B-56.

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A: No. A utility can determine the order in which water sources are used as long as they are defined procedurally.

44. Q: Do we need to perform a study to identify safe shutdown instrumentation?

A: A study is probably not needed since such a list was required for Appendix R. Also the EOPs should already identify the instrumentation being used to achieve and maintain safe shutdown.

45. Q: Can credit be taken for diesels that have dedicated 4/42ID makeup capability?

A: Yes. Using the AC-independent approach, dedicated water makeup capability may be relied upon if the .

diesel does not normally provide power to the '

essential and non-essential power supplies (see the definition of station blackout). The support systens for such diesels r.ust also'be independent of these

• power supplies in order to credit their operation in a station blackout. In order for the diecel to be credited as an AAC machine it must also meet the criteria set forth in Appendix B of NUMARC 87 00.

-- - - - - - - - - - - - - _ _ , _ , . - _ _ m 7----.,y_

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affected by the temperatures reached in the steam tunnel?

A: Temperature sensors for detecting high energy line breaks are located in the main steam tunnel. In a station blackout, bulk air temperatures may rise to a ___

level that could trip the RCIC turbin k - - -

85. Q: What assumptions apply to the area on the other side of a door that may be considered for providing supplementary ventilation?

A: To take credit for opening doors during a station blackout, the adjacent area must be sufficiently large to maintain a relatively constant temperature when considering the additional heat loa"1 imparted to the room from the dominant area of concern. In addition, the adjacent room's bulk air temperature should not exceed the initial wall temperature in the dominant area of concern due to heat sources located

. in that adjacent area.

86. -Q: What is the assumed location of doors?

O

i 130. Q: Are breakers that are necessary for the operation 6f AAC power required to be operated from a controller or can they be operated manually?

A: Manual operation of breakers is allowed as long as it can be demonstrated that the necessary actions can be carried out such that the AAC power source is available within one hour. Alternate AC that is considered available within 10 r.inutes must meet the requirements of NUMARC 87 00 Section 7.1.2.

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4. Q: In the case of AAC configuration 2B, if the Llacked-out diesel's batterien control the cross-tis break'ers and wo assume that the batteries fail, it would then be necessary to provide operator actions to supply power to the blacked out unit. Does this mean that the AAC rource would not be eble to ha considered as a 10-minute U source?

l' A.s. 1 s' 'o. In order for an AAC source to meet the 10-minute 1

criteria, circuit breakers necessary to bring power 1 to mate shutdown buses must be capable of being actuated in the control room in that period.

132. Q: On AAC configuration 2B, are cross-ties required for both trainJ7 -

. . 2rrato to NP! ARC 37-00 POgo 8

'35. P. C The "A" buses should be connected to each other and the "B" buses should also be connected to each other. For Unit 2 change the "A" to "B" and the "B" to "A".

36. P. E Appendix E, Saction E.3.2 - in second to last sentence change "72 F" to "68 F" and in last sentence insert

"(79 F)" after "44 C."

37. PP. F-1 through F delete in entirety and replace with Appendix F, Revision 1 dated September 26, 1988 and the Topical Report dated September 26, 1988.

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GUIDELINES AND TECHNICAL BASIS FOR NUMARC thTTTATIVES f NUMARC.8700 _

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deug niew u,r,,aaen uacuu,. rus don u be,ed on operatug s, eerie-n aa nan concerning she operabulty of mariou classes ofequipment e.xposed to elemed temperatures.

in a ssadon blackout. forced coolkg will be ton to nest plant areas and the potendal aists in l Canddon 1 erasfor bulk air temperatwee to rke q w 120 *F. For most meckedcal and electical 1

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egspment and in. .=' nfound k Conddon i dominent areas, severnare rkes q w 120 *F would likely not adnesely geet operabilley.

Candnaa2 Conddon 2 roonss we likely so include a relantwly sub.nandal heat generados nowre and a small room geometry. Thou conditions are more typical of roo=uss containing steen.drinn nunkeup pumps, such as RCICS and AFWS whlch are generally qualytad or daisned to operms in elemsted

'*Teraturst.

The NRC has considered equipment operability during nation blackout condidons (see '

Jacobus (19871). One of the conclusions of this revsew is that earnain elsanes of comnents (e.g.,

relays and swisehn) will likely rema!a operable in thermal environmeus of130 *F to 30 *Ffor up to ei3 ht hours. While the Jacobus study was not assessin. she general assumpden of equipment operabdityfor Condidon 2 shermal ennronmous is considered ulld because (!) only afour hour ssados blackout ennt is considered. and (2) in praedce, leu than the fullfor hows would be involved since there would be a pened of thermal buildup during the pont.end of the station Mackout omnannt.

Candaeal Conduien 3 reenn reprenant classes of skarmal environments where. plant.npechte seasideradon

• • y be ePProprinne.

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Appendin F proMas a mathedfor assenkg the operability of equipmeu, exposed a Condiaan 1,2, and 3 am4ennents. -

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NUM ARC INTT1ATTVES _

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7 c tb) Bauery capacity is re.tuce.iIf the electrolyte tempe stwe drops dgnifcantly below design temperatures. Clan batteries are houud in mismic Category i strutwas, and are not typically subjected w the direct e anernal ennronment. Therefore, the temperates decrease in the bettery room is not dgnifcant ner a fo p riod. Also, the mass of battery electrolyte is adicient to raskt dgnyteent temperstwe drops over afow pcied du to lower batury room temperstwas sace batury cell materials we not *Bfelen thermal conductors.

Thergfore, a decrease in banary emacity du a temperatwe decreases k elecrolyu sader anion blackout conditions does ne marratpnherconsideracion.

C) Carreet Macm HabitaNiiry Control room habitabitity la not an impo.sant couributor w amion blackout risk, panicut.1rlyfor eve I durations. NUREG.!332 poina ow Ihas the donunant accident ugunces involve etther an early corei or a subseguns ton of core cooling (ne Appendix C, hJREG.1032 for a more complete discussion of s blackout accident uguences). Both uqunen are dominated by thefallet of automatic equipme function on denand. Even these evenu have failee probabilities ofleu than 1% per ennt, ref7ec excepdenally hugh reliability of thou systems and componsnu. With respect w human error, such as du t i habitability concerns. NUREG 1072 nates "The posential efect ofoperator error esunng lou of has not beenfound to be a larte conmbuwe to core damagapequency, fadequate amain NUREG.1032, pote C.13). Since NUMARC laisiatin 2, as provided in Seedon 4 guidelines, stainint and procedwes di enst, the concern regarding ope-ators' ability w perform cognidw ta m .L T _. h td,. m,. l.- A i

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74hhabitability was never an issu, Studies suggen that long term occupancy in higher temper ennronmenu does not prewn performance of task of ursou ddiculties (see Eickna (1943] and imells (1946]for nulltay appliendons). Such audies how been the basis of gundanes in \

industry kendbookt (e.g., ASHVE (1930] and ASHRAE (1983]). ASHRAE in panicular, cor humidity, and preuure sad concludes that light work at 110*F and relative humsdidos up u 30% w anielerable.

Before the naden blackout ennt, it is auumed that the control room it at 78 *F and about Althoug h temperarve increases me~ be expected du w len of HVAC, the relative hunu'dit appro.timately 30%. Guidance provided for military app!! cations may enablish a technical b 4

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CUIDELINES AND TECHN! CAL BASES FOR NUMARC INITIAT!YES NUMARC 37 00 DRAFT Septe:bar 26, 1988 . Revision 1 (5) Establish reasonable assurance by following any of the approches discussed in this appendix.The NUCSBO equipment operabillry databue (EODB) may contain informadon to help suppon the evaluadon.

Determine the station blackout temperature fcr the STEP 1 dominant area of concem, Tx , in accordance with Section 7.2.4 of NUMARC 87 00 V

Identify Sution Bla:kout

. STEP 2 '

Response Equipment i 4 s 1

W e .- $ ,

De'termine the Tir?.e Period that Assume the Equipment Must

, . Equipment Must Remain Remain Operable For the Entire STEP 3 rable for the Appropriate Duration of the Star.:en Su .. . n Bla: Lout Coping Method Bla: Lout j ., 0.e., one, two, or four hours)

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I Does the Equipment

• l Fit into a Oenen: YES Reasonable Assurance of STEP 4

• Cs'esory?(see Table F.1 >

i Operability is Established

' j and Se:tions and

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Establish Renonable Assurarse -

of Operability Using the Methods STEP 5-

. Dis:uned in Sc:: ions F.1Through i

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. CL*!DELINES AND TECHNICAL BASES FOR NL' MARC INITIATIVES NL'M ARC 37 00 DRAFT Gepte:ber 26, 1988 . Revislin 1 UY supplies 8 small rooms or en:1 s), and (3) the absence of heat remov&! capability in a station blackout Wthout operator nedon.*Ihese areas ari have been de.armined to be:

(1) Steam Driven AFW Pump Room (PWRs only);

(2) HPCUHPCS Room (BWRs only);

, (3) RCIC Room (BWRs only); and, (4) Main Steam Tunnel (BWRs only).

It should be noisd that any alte specific plant area found meedng the three futors above aheld also be considered to be a dominant arei of concern, STA' MON BLACKOUT EQUIPMEFT equipment lacsted in dominant arus of concen whi:h are used to bring the plant to safe shutdown during staden b!xkoyt conidons.

I STATION BLACKOUT TEMPERATURE (Tore) . the average steady sute bulk air 'emperature in a dominant area of con:em during a four hour station bla:kout.

l. STAT 10N BLACKOUT OPERABILITY TEMPER ATURE ITopp) the temperature for whi:h reasonable assuran:e

) of operability has been established for a spe:ifi component or for an equipment category. This temperature is established for a variety of equipment cawsories in the Appenda F Topical Report, and may be established for indis idaa! eq uipment using the a; pros:hes described herein.

SIMILAR EQUIPMENT . equipment w hose chara:teruti:s a : such that; (1) the limiung sub-componenu have comparable or less limiting thermal properties; and, (2) the lirruting materials has e comparable or less limiting therma! prt.,perties.

In the context of statioa bla:kout,limiring sub compossau or timing m. steri.21s are those sub componen or materials whi:h are most susceptible to signifirst degradnion at elevated temperatures. The appli: acon of this prin:iple is illustrated in Enample 3 c. Section F.2.4, e

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