ML20150B093

Informs of Initiation of New Multi-Plant Action A-22, Implementation of Station Blackout Rule,10CFR50.63, to Be Effective on 880721.Encl Fr Notice to Be Forwarded to Licensee

ML20150B093
Person / Time
Issue date:	06/23/1988
From:	Tam P Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
References
FRN-53FR23203, REF-GTECI-A-44, REF-GTECI-EL, RTR-REGGD-01.155, RTR-REGGD-1.155, RULE-PR-50, TASK-A-44, TASK-OR TAC-40577, NUDOCS 8807110275
Download: ML20150B093 (19)

Text

_ - _ _

June 23, 1988 9,. DISTRIBUTIONS

. CentraluFile/PDI-4 Filo MEMORANDUM FOR: All NRR Project Managers PTas THRU: John F. Stolz, Director-Project Directorate I-4 Division of Reactor Projects I/II FFCM: Peter S. Tam, Project Manager Project Directorate I-4 Division of Reactor Projects I/II

SUBJECT:

MULTIPLANT ACTION A-22 IMPLEMENTATION OF THE STATION BLACK 0UT RULE, 10 CFR 50.63 l This is to inform you of the initiation of a new multiplant action', MPA A-22, l as follows:

Title of MPA: Implementation of The Station Blackout Rule, 10 CFR 50.63 Lead PM: Peter S. Tam (PDI-4, J. Stolz, Project Director)

Lead-Reviewer: A. Paul Gill (Electrical Systems Branch, F. Rosa, Chief)

! Priority: 1 l Dates: Regulation published on Ju e 21, 1088, to be effective July 21, 1988.

PM Action: Licensees / applicants would find out a.mJt this rule through the Federal Register, as well as thc e their participation in NUMARC. There is no need for foru . PM action. However, please be sure ycur licensee has received a copy of the regulation. A copy is enclosed for your use.

TAC nurrbers: They are being requested by the lead FM for each reactor unit, and will appear in your PM Report in the rear future. Each operating and NTOL LWR should receive a TAC number.

The Staticn Blackout Rule (and the associated Regulatory Guide 1.155) requires that light-water-cooled nuclear power plants be capable of withstanding a loss of offsite and onsite energency ac power for a specified duration and nalntaining reactor core cooling and containnent integrity during that period. The Rule l

and R.G. 1.155 provide acceptance criteria for the evaluation. l l

8807110275 880623 K.f0 PDR OTECI GELA-44 PDR i

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2-The specified duration would be determined for each plant based on a comp 3rison of the individual plant design with factors that have been identified as the main contributors to risk of core melt resulting from station blackout. These factors are: (1) the redundancy of onsite emergency ac reliability of the onsite energency ac power sources, (power sources. (2)

3) the frequency of the loss of offsite power and (4) the probable tine needed to restore offsite pcwer. The regulaticns are anended by adding a new paragraph 50.63 and by adding a new final paragraph to General Design Criterion 17, Appendix A of 10 CFR Part 50.

The rule-making represents the resolution of Unresolved Safety Issue (USI)

A-44, which was opened as a consequence of closecut of MPA B-63. The NRC receive.d extensive centrents from the general public on the draft regulation, and has worked closely with the industry group NUMARC (Nuclear Managenent and Resources Council).

The licensees have the next action, which is submittal of information in accordarce with the new 10 CFR 50.63(c)(1) within 270 days. Applicants that bectne licersees, likewise, have 270 days after OL issuance to submit the needed information. Submittals are expected to folicw the standard format developed by NUMARC, which is presenting a series of training sessions to utilities.

I shall provide status infortiation and additional guidance in future nenoranda.

If you need detailed inforrcation or copies of the Rpg. Guide, please feel free to contact r,e (2-1314). -p i Pete'gna W/Project Manager r S. Taml Project Directorate I-4 >

Division of Reactor Projects I/II cc: T. Murley J. Lainas F. Miraglia A. Serkiz S. Varga B. Beger l F. Rosa l P. Gill i D. Ciutchfield l G. Iblahan LA:PDI-4,. PM: POI-4 PD:fDIb Sidris PTam:lgn JStol 6/ d 88 6 /23 /88 6/ -

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7 23203 Rules and Regulations r* > a +'~

Vol. 53. No 119 Tuesday. lune 21, 1968 I

Tras secton of the FEDERAL REGISTER essential for preserving the integrity of , that station blackout could be an contains regulatory documents ham 9 the reactor core and the containment important contributor to the total risk general apc4Mey and le%! eNect, most buildmg. respectively. The reactor core from nuclear power plant accidents.

of ech are keyed to and cowed in the Code of Federal Regulatona, whe:h is decay beat can also be removed for a Although this total risk was found to be I

limited time period by safety systems small and not undue, the relative C that are independent of ac power, importance of the station blackout The Code del Federal % tons e soid The term "station blackout" means accident was established. Subsequently, try the S@enntendent of Document the loss of offsite ac power to the the Commission designated the issue of Pnces of new tocks are hated in the essential and nonessentiel electrical station blackout as an Unresolved frst FEDERAL REGISTER issue of each buses concurrent with turbine trip and Safety !ssue (USl); a Task Action Plan week.

the unavpilability of the redundant (TAP A-44) was issued in [uly 1980, and

__ onsite espergency ac power systems studies were initiated to determine (e.g., as a result of units out for service whether additional safety requirements NUCLEAR REGULATORY of maintenance or repair, failure to start COMMISSION on demand, or failure to continue to run were needed. Factors conaldered in the analysis of risk from station blackout 10 CFR Part P after start). lf a station blackout persists included; (1) ne likelihood and dura tion for a time beyond the capability of the of the loss of offsite power;(2) the Sten Blackout ac independent systems to remove decay heat, core melt and containment reliability of the onsite ac power s> stem; and (3) the potential for severe accident AGElecy: Nuclear Regulatory failure could result.

Commission. The Commission's existing regulations sequences after a loss of all ac power, establish requirements for the design induding consideration of the capability Actioec Final rule. to remove core decay heat without ac and testing of onsite and offsite electn.e suesasAny:The Nuclear Regulatory power fer a limited time period.

power systems that are intended to ne technical findings of the atafre I

Commission is amending its regulations reduce trie probability of losing all ac .

to require that light water-cooled power to an acceptable level. (See studies of the station blackout issue are l nuclear power plants be capable of presented in NUREG-1032 "Evaluation l General Design Criteria 17 a nd 18.10 withstanding a totalloss of alte:nating CFR Part 50. Appendix A.) The existing of Station Blackout Accidents at Nudear current (ac) electric power (called Power Plants, Technical Findings regulations do not require explicitly that "atation blackout") for a specified nuclear power plants be designed to Related to Unresolved Safety issue A-duration and maintaining reactor core assure that core cooling can be R" Additionalinformation is provided  ;

cooling dunng that period. This maintamed for any specified period of in supporting contractor reports: i requirement is based on information loss of all ac power. NUREG/CR-3228,' Station Blackout i developed under the Comrnission's As operating experience has Accidnt Analyses," published in May 1 study of Unresolved SafetyIssue A-44, accumulated. the concern has arisen 1983; NTREG/CR-2989, "Reliability of "Station Blackout." ne amendment is that the reliability of both the onsite and Emergency AC Power Systems at intended to provide further assurance offsite emergency ac power systems Nuclear power Plants," pubhshed in July that a loss of both offsite power and might be less than originally anticipated. M NUREG/CR-3% "Collection and onsite emergency ac power systems will even for cesigns that meet the Evaluation of Complete and Partial not adversely affect the public health requirements of General Design Crilen.a hs of Offs,,in Pown at Nudear and safety. 17 and 18. Many operating planta have pg,,, pggg, publishd b February EFFECTTYE DATE july 21,1968. experienced a totalloss of offsite power, 1965; and NUREG/CR-4347, "Emergency

,,, ago, en,gg7,, and more occurrences can be expected Diesel Generator Operating Experience, r ce 1981-1983." published in December 1985.

Aleck Serkiz Division of Reactor and g e[ De major results of these studies are Plant Systems, Office of Nuclear Regulatory Research, U.S. Nudeat has induded man instances when given below.

dieselgenerators alled to start. In a few

, ,g gg ,,, g Regulatory Commission, Washington, characterized as those resulting from DC 20555, Telephone- (301) 492-3ns.

smasEsnAny semaAATsoet *d*' [*,' d he n r [lant. centered faults, utilityindoced grid systems. During these events, ac power lackout, and severe. weather tack 3Nund was restored in a short time without any failures f ffsite p wer sc trees. Based

%e alternating current (ac) electric ' on operating experience, the frequency

"["'th re its of the Reactor of totallosses of offsite power in Power for essential and noneuential operating nudear power planta wae service in a nudear power plant ta Safety Study (WASH-1400) a showed supplied primarily by offsite power. found to be about one per to site. years, The median restoration time was about Redundant onsite emergency ac power eyatems are also provided in the event , py, l$ $g"* 'g,*,$

,w, o, ,,,,i e.oo,, .i w n sim,. sw.

one.balf hour, and 90 percent of the offalte power lossee were restored that all offsite power sources are lost. washnsion.oc usa cop of pm.4 Rese sy tema provide power for within a; proximately 3 bours (NUREC/

docanis emho be pechased Wasm UA CR-3992).

various safety functiona, including reactor core decay best removal and $" *y  %%"

ooaments. us covement rnni>as ONe. P o

• ne review of a number of representative designs of onsite containment heat remosal, whk.h are sou s'ost wenven. DC mns-tosi emergency ac power systems has 4)g h r ti e h on ge U2g

232 Federal Registor / Vol. 53, No.119 / Tuesday, June 21, 1988 / Rules and Reg'ulations indicated a var cty of potentially design and operational characteristics, acceptable period of time). and to have important f ailure causes. Howes er, no plus site-dependent factors (such as procedures and training to cope with single improvement was identified that anticipated weather conditions) such an event. Licensees may use an could result in a significant introduce a level of variability which alter ate ac power sourceif that source irnprovement in os erall diesel generator warrants a need for plant.s'pecific meets specific criteria for independence reliability. Data obtained from operating coping analyses to provide greater and capacity and can be shown to be experience in the period from 1976 to issurance that core cooling can be available within one hout to cope with a 1980 showed that the typicalindividual maintained until ac power is restored. station blackout. A coping analysis is emergency diesel generator failure rate Thus the Commission believes that not required for those plants that choose was about 2.5 x 10 8 per demand (i e.. I 50 63 of 10 CFR Part 50 will bring this alternate ac approach if the one chance of fciture in 40 demands), about a significant increase in alternate ac can be demonstrated by and that the emergency ac power protection to the public health and test to be available to power the system unavailability for a plant which safety, As a result of stauon blnckout shutdown buses within 10 minutes of the has two emergency diesel generators, coping analyses, improved guidance will onset of station blackout.Use of an one of which was required for decay be provided to licensees regardmg alternative ac source, one that beat removal, was about 2 x 10 8 per maintaining minimum emergency diesel minimizes common mode failure,is a demand (NUREG/CR-2989). generator reliability to minimize the preferred option since this approach wil!

• Compared to the data in NUREC/ probabdity of losing all ac power. In also benefit other safey concerns.

CR-2983, updated estunates of addition, the Commission is amending . On the basis of station blackout e:nergency diessl generator failure rates its regualtions by adding a new i 5063 studies conducted for US! A-44 and indicated that diesel generator to require that all nuclear power plants presented in the repor's referenced reliability has improved somewhat from be capable of coping with a station above, the NRC staff has developed 19"'6 to 1983. For the period 1981 to 1983, blackout for some specified period of Regulatory Guide 1.155 entitled "Station the mean failure rate for all demands time.The period of time for a specific Blackout," which presents guidance on was about 2.0 x to 'per demand (i.e., plant will be determined based on a (1) maintaining a high level of reliability one chance of failure in 50 demands). comparison of the individual plant's for emergency diesel generators. (2)

Howeser, the date also indicatc that the design with factors that have been developing procedures and training to probabihty of diesel generator failures identified as the main contributions t restore offsite and onsite emergency ac during actual demands (i e.. during nsk of core damage resulting from power should either one or both become losses of offsite power)is greater than station blackout. unavailable, and (3) selectin a plant-that danng surveillance tests (NUREG/ nese factors which vary spec fic acceptable station b ackout CR-4347). significantly from plant to plant because duration which the plant would be

• Gnen the occurrence of a station of considerable differences in design of ..

h blackout, the likelihood of resultant core phnt electric power systems as well as [, pag,g

, age. Appl cat n o the e ods in damage or core melt is dependent on the site. specific considerations, include: (1) this guide would result in selection of an reliability and capability of decay heat Redundancy of onsite emergency ac acceptable station blackout duration remont systems that are not dependent power sources (i e.. number of sources (' R ,2 4' 8. or to houn) which depended on ac power. lf sufficient ac- minus the number needed for decay heat C

independent capability exists. removal). (2) reliabihty of onsite rela ed a act st es a ceptable to the additional time will be available to emergency ac power sources (usually staff. However, applicants and licensees restore ac power needed for long. term diesel generators), (3) frequency of loss. could popose alternative methods to ,

coohng (NUREG/CR-3226). of offsite power, and (4) probable time those specified in the regulatory guide m

• It was determined by reviewing to restore offsite pow er. The frequency order to justify other acceptable design, operational and site-dependent of loss of, and time to restore, offsite durations for station blackout l factors that the expected frequency of pow er are related to grid and capability. Additionally, the regulatory core damage resulting from station switchyard reliabilities, historical weather data for severe storms, and the gu!de on station blackout presents blackout events could be maintained guidance on quality assurance and near 10

• per reactor year with readily availabihty cf nearby alternate power specifications for attemate ac source (s) achievable diesel generator reliabilities. sources (e.g , gas turbines). Experience and non safety related equip. ment provided that plants are designed to ha.s shown that long duration offsite required for coping with station cope with station blackout for a power outages are caused primarily by blackout.ne equipment installed to specified duratien. The duration for a ses ere storms (hurricanes. ice, snow,

. rneet the station blackout rule must be I specific plant is based on a comparison e tc.). irnplemented so that it does not degrade I of the plant's characteristics to those The objective of the rule is to reduce the risk of severe accidents resulting the editing safety related systems.nis factors that have been identified as the is to be accomplished by making the ms.in contributors to risk from stotion from station blackout by meintaining blackout (NUREG-1032). highly reliable ac electric power systems non safety related equipment and. as additional defense in depth. independent to the extent practicable The staff s technical fmdmgs show assuring that plants can cope with a from edsting safety related systems.

that station blackout does not pose an undue risk to public health and safety. station blackout for some period of time. The guidance provided in the regulatory ne rule requires all plants to be able to guide illustrates the specifications that ne findings summarized above show the staff would find acceptable for non-that recovery from loss of offalte power cope with a station blackout for a specified acceptable duration selected safety systems and equipment. The occurs for the most part in less than 4 on a plant. specific basis. Alllicensees quali'y assurance guidance for the non-hours. emergency diesel generator and applicants are required to assess safety related equipment for which there reliability is high (i.e..>0.95), and that are no existing NRC quality assurance given a station blackout the likelihood the capability of their plants to cope with a station blackout (i e., determine requirements (e g., Apper. dix B.

of core damage is more dependent on that the plant can maintain core cooling Appendix R) embody the following decay heat removal systems that are e:ements:(1) Design control and non.ac-dependent. Howes er, plant with ac power unavailable for an

ftderal R:gister / Vol. 23, No.119 / Tuesday, June 21, 1988 / Rules and Regulations 23?05 procurement document control,(2) be viewed as being in the same accident t

j instructions, procedures and drawings, would resolve this issue without  ;

prevention context as the ATWS rule rulemaking. Thirty nine of the industry (3) control of purchased material, (l 5082) and the fire protection rule i le'!ers supported NUMARC's submittal.

equipment and services, (4) inspection. () 50.48)in that it recognizes, as the  !

(5) test and test control,(6) inspection, NUMARC proposed a fifth initiative (see 1 other two rules recognize, multiple item 21) by letter dated October 6.1987. l test and operating status (7) non. failure possibilities resulting from conforming items. (8) corrective action, On the other hand. the Union of common cause effects that should be Concerned Sc.ientists, the lihnois l (9) records. (10) audits. NRC inspections addressed. This concern has been will focus on the imp!cmentation and Department of Nuclear Safety. and the recogaized in the introduction to citizens group supported the the effectiseness of these quality Appendix A of 10 CFR Part 50.

controls as desenbed in the regulatory Commission's objectis e in the propest J guide. Proposed Rule rule, but did nut believe the rule and  !

. On March 21,1988, the Commission ewdance associated with the rule went Based on the rule and regulatory for enough to reduce the possibility of a l guide, those plants with an already low published a proposed rule in the Federal l l' risk from station blackout would be Register (51 FR 9829) that would require aerious accident that could be initiated by a totallos. if ac power.

, required to withstand a station blackout (1) light water cooled nuclear power

for a relatively short period of time and Every letter was reviewed and plants to be capable of coping with a.

probably would need few,it any, station blackout for a specified duration, considered by the staff in formulating modifications as a result of the rule. *d e sus i de n' the final resolution of USl A 44. Because Plants with currently hi er risk from na du t nf, h of the large number of conunents. It was station blackout would e required to plants as currently designed are able to n t pracucal to pnpare fonnal withstand somewhat longer duration cope with a station blackout, A 90 day responses to each one separately.

comment period expired on June 19. However, since many comrner.ts w ere b!ackouts. Depending on their existing capability, these plants might need t I on similar subjects, the discussion and April 3,1986 (13 days after the response to the comments have been make hardware modifications (such as gr uped into the following subjects: 8 increasing station battery capacity or proposed rule was published), the NRC condensate storage tank capacity)in published in the Federal Register (51 FR 1. Quality classinca' ion nf modt$ cation (

order to cope with the longer station 11494) a notice of availabihty and I whether the backnt analysis adequate!>

blackout durahon. Re rule requires that request for comments on a drafi in:plements the Backnt Rule.

eoch light.wster cooled nuclear power regulaory guide entitled "Station s. Cost-benent and whether I 50 63 neets plant licensed to operate must be able to Blackout"(Tesk Si 501-4). His draft "substantial incree n in the overau protection guide provided guidance f r licensees to of the pubiic health and safety withstand for a specified duration and

4. Whether NRC should regmre substantial recover from a station blackout. De rule * *[ly# with the' proposed stahon . improvementa in safety that to beyord those requires8"each plant'to{erform a coping on the proposed ruTe also includeders commentmg proposed in this rulemabs.

s. m need for generic rulemakmg.

"[*) ,j ba "kerefor comments on the draft regula tory guide. 6. AppdcabiL*y of the proposed i Sn r4 to and a descri tion of procedates Responses to these comments provided speaf;c plants.

estabbshed or coping and recovery. If below address the public Nmments on 7. Plant specinc features and cap.bihu%

modificatiora to equrpment or plant the draft guide as well as on the 8. The souru tenn md to asumale l procedures are necessary, these are to proposed rule' 4 "" " '

be identified and a sahedule prosided

'*"."Specin' 9 city on the exteni of required  !

Comments on the Proposed Rule coping studies.

fot implementing such changes.

De Commission receives 53 letters to. Acceptable duration for cop:ng mth a It should be noted, based on all commenting on the proposed rule.'

evidence that staff has on hand, that no Forty five of these were from the "*Nd fobiternate or daerse se power undue risk exists with, or without, the sources promulgation of the station blackout nuclear industry, compnsed of electric 12. Trends on the reliability cf ac power '

rule. However, station blackout may still utilities, consortiums of electric utilities. sources. I remain an important contributor to vendors, a trade association. and an 13 Sharins of emerseecy dieset tenerators

• architect / engineering firm. Other letters between unes at mulirunit sites.

residual risk. his station blackout rule were submitted by the Union of will enhance safety by accident 14. Cemf cation of the defuntions of station prevention and thereby reduce the Concerned Scientists, the Departicent of blackout and diesel generator failure.  ;

likelihood of a core damage accident Nuclear Safety of the State of Dlinois, a * *' UP'*ib'Y '"d 'IIO** *I " *I being caused by a station blackout occurrence. his does not rnean representative of the Professiocal Reactor Operator Society, a citizens ]6 e ical commerts on Nt,rREG m

17. Relationahlp of USl A-44 to other NRC l'

group, a consultant, and three I bowever, that furtber anhancements in Generic luves.

j reducing the overall residual risk are not individuals. bargely, the industry 1a. An ehemative of plant.speclSc achievable by additionalimprovements comments were opposed to generic probabilistic assessments.

rulemaking to resolve the station 19 Pmcedures and operator actions denng in severe accident management, given the assumption that core damage occurs, blackout issue.De Nuclear station blackout.

Management and Resources Council 20. Sc.hedule provisions in the proposed whether from station blackout (NUMARC), formerly the Noclear i 50 63.

sequences or other causes (such as "'

small or large loss of-coolant accident -

Utilities Management and Resources " "##I "

l Committee, submitted, along with its he comments and responses to each J sequences). Initiatives that provide such i comments on the proposed rule, a set of of these eubjects are presented on the safety enhancernents (through 1 four industry initiatives that it believes following pages.

improvements of core damage

] management procedures) are currently , copi er, avea.ble for p.bhc inspectron and s betng pursued apart from the atation e m 6rst four e bi.cu er aan on =ka the blackout rule. Derefore, this rule should copying so, sw o, sac p.buc Drueeni moon comrmamonem epectocatty revested pubtle ai im H strat. Nw w n4sw. Dc commeats wh+n the prop +ad rila *** >=6M*d

~

, l 23206 Federal Register / Vol. 53. No.119 / Tuesday. June 21, 1988 / Rules and Regulations L Quality Classification of =

modJicationr: however, detailed Afodifications 3. The relationship to proposed and <

guidance is provided in Regulatory existing regulatory requirements should I The Commission requested comments Guide 1.155 dealing with quality be considered further. t on whether the staff should give further assurance and equipment specifications 4. Potentialimpacts of differences in consideration to upgrading to safety for non safety related equipment. Any facility, type, design, or age should be grade the plant modifications needed (if safety.related equipment used either considered further.

any) to meet the proposed rule. presently, or in modifications resulting Upgrading to safety grade would further from this rule, should meet the criteria 5. The reduction in risk from offsite releases to the public has been ensure appropriate licensee attention is currently applied to such equipment. os erestima ted, paid to maintaining equipment in a high The technical analyses performed for On the other band. the Ohio Citims ,

state of operability and reliability. USI A-64 (NUREG-1032) show that for Responsible Energy (OCRE) and the Comments-The prevailing view by plant-centered events (i.e., those events industry on this subject is represented Union of Concerned Scientist ,

in which design and operational commented that the backfit rule should J by the following comments submitted by characteristics of the plant itself play anot apply to the proposed rule. OCRE NUMARC: .1 role in the likelihood o!!oss of offsite took the position that "application of the. -

Quohry classificctica is mecessey- power), and area or weather related backfit rule to [N I . Equipment used to prevent or respond to a events (e.g., grid reliability or external is plainly illegal,,RC) rulemakings ' '

• and the Commission station blackout should be sumciently influences on the grid) are the dominant is not empowered to consider costs to available and operable to rr.eet its required function. To this extent, the Commission's causes of loss of offsite power. Neither licensees in deciding whether to impose desire that appropriate attention be paid to seismic events nor events related to new requirements. The Union of maintaining a sumciently high state of single failure causes were found to be Concerned Scientists commented that major contributions to loss of offsite the cost benefit anal > sis should not be po et d pa eis i:h h od for Power. Therefore. both the staff's

. .hievin applied in this case because safety findings and public comments receis ed improvements are needed to secure itself. a *g this objectn e. Specincally, b .ssfety grade" classincanon scheme decs not solely equate with h gh states of do not support an explicit need for plant compliance with existing NRC equ:pment operabihry and rehabihty. Such modifications for coping with station regula tions. specifically General Design classincation s) stems too ohen can become a blackout to be seismically qualified. Criterion 17 Electric power Systems

' " (Appendix A to 10 CMt part 50).

foIpr .a$he sit ele f s> stem functionality.

so ht b)  : le an ach e d modifications which meet criteria the ac fI  !)s e la in Duquesne Ught agreed with this view .

somewhat less stringent than generall . account by the staff in revising the draft and expressed the following comments: db f d ' mst n of NUREC.-1109. *Re ulatory An) plant modifications or ad&tional

' fate re equi me t m$d fic t o s'to eIt Backfit Analysis for the Reso1ution of equipment required to meet the proposed rule all safety grade-related criteria would Uriresolved Safety Inue A-44. Station should not be specined safer) grade. For be more burdensome and expensive and Blackout," and a separate appendix that

'd would likely achieve only a very small addresses the factors in 150.109(c) was ac d en ice f t at tn e further reduction in risk. The majoe added to that report. All but Item 2 event of a loss of power condihon there is no contributors to the resid;al risk of loss above are on the same subjects as necessity for specifpng safety grade since of offsite power are adequately dealt letters from other commenters and are adequate rehabihty can be obtained through with by modifications which conform to discussed in more detail under subjects normal sur eillance test na and the proper maintenance of commercial power plant the quality assurance and equipment 3 (Item 1),6 (! tem 4). 8 (ltem 5), and 17 equipment. ne cost &fference in sdety specificatron guidance provided in (Item 3) in this section. NUMARC's item ,

grade vs. comme.tal grade mo&0 cations is Regulatory Guide 1.155. 2, the potential impact on radiological  !

signincant and must be emphasizei exposure of facility employees, would

2. IUhether the BocAfit Analysis need to be assessed in detail only if it

.The opposite point of view was taken by the Illinois Department of Nuclear A dequately /mp/eteents the BocAfit Rule were a major factor in the value impact Safety, in addition to comments on the merits anahs He effect Ini I gicat of the proposed rule. the Commission exposum on facilHy employen. if any.

No crest should be gnen for the capabihty specifically requested comments on wu ex Mm% smaH n companson sf equipment to respond to a station blackout whether the backfit analysis for this rule t the reduction in radiological expo unless the equipment was origmally designed. constructed, inspected adequatel implements the Backfit Rule. to the public from accident avoidance.

perfomience te-ted, quahtied.certined foe the i 50'100 o O CFR Pad 50* Therefore this factor would have no intended safety.related purpcse, and the Commente-The Commission Impact on the overall value.impa:t t equipment is maintained to the highest received two differing views in response analysis, l industry safety standards. Contrary to OCRE's'and the Union of '

to this request. On one hand, NUMARC Gulf States Utilities commer.ted. expressed the view that the proposed Concerned Scientists' comments, the ne proposed rule does not provide rule does not meet the backfit rule Commission may subject the rulemaking sufncient direction on the quahry standard because the anal) sis of the pmcus to Wnal contmk Monom the Commission is empowered to classincation of plant mod 45 cations that may acton set fodh in l WO9(c) wen not ,

be required to meet the rule. * '

• the qua:iry adequately considered by the staff. consider the costs of incremental safety I classincation of plant modificativns Specifically, NUMARC stated: improvements which go beyond the implemented to meet the proposed rule level of safety necessary to ensure no

1. Installation and continuing costs should be commensurate with class:fication undue risk to the public health and s the system the) support. associated with the backfit have been safety. Se e UCS. et ok v. NRC D.C. Cir.

underentamated.

Response-The proposed I 5063 does Nos. 85-r57 and 86-1219 (August 4. l

2. Potential itnpacts on radiological 1087). The improvements embodied in iot specifically address the topic of  !

safety classification of plant exposure of facility employees should be 150 63 go beyond the level of safety '

further addressed. necessary to euure no undue risk.

l

, Federal Registee / Vol. 53, No.119 / Tuesday, June 21, 2980 / Rules and Regulations 23307 Finally, contrary to the Union of low. Commonwealth Edison and other percent to almost 140 percent peater Concerned Scientists' comment on GDC uti!ities felt that performance of an than the estimates in NUREC/CR-3840, 17, new station blackout measures analysis to determine the maximum depending on the specific modification cannot be imposed on licensees as a duration a nuclear plant could cope with considered. On average, the cost matter of compliance with GDC 17, a station blackout would be under the compliance exception in the estimates for hardware backfit were substantially costlier than what is found to be approximately 80 percent backfit rule, i 50109(a)(4)M. CDC 17 estimated in NUREG-1109. Industry also greater than estimated in NUREG/CR-does not explicitly require that each expressed concern that the 3840. However, the cost estimates in plant be able to withstand station interpretations associated with the blackout for a specified time,or that NUREG/CR-3840 were not used by the propased rule could lead to substantial staffin the value impact analysis in the each licensee perform a coping costs above those addressed by the draft version of NUREG-1109 where assessment and make whatever NRC staffin its backfit analysis. AIF estimates approximately 100 percent modifications may be necessary in the commented that 'The estimate of120 greater than the NUREC/CR-3840

, light of that assessment.Nor are any of NRC man. hours per plant (for NRC these highly specific requirements esumates were used.Therefore the review] * *

• appears inadequate to revised cost estimates used in the final

{ logically compelled by any part of GDC account for technical review and

17. Moreover, CDC 17 has nes er been value impact analysis are not interpreted by the staff or the evaluation of the determination of significantly different from the estimates maxircum copmg capability and of the used in the draft version.

Commission to contain these specific description of station blackout requirements. Thus. to impose them Industry's comments on the costs to under GDC 17 would amount to a procedures which the rule would require assess a plant's capability to cope with each licensee to submit." a station blackout were based on the backfit which resulted from a new staff and Commission interpretation of GDC (B) Seseral commenters expressed the proposed rule that required an 17- view that the NRC failed to consider all assessment of the maximum coping ne issue in this rulemaking is the risks associated with a station capability and the potentially whether sorne additional protection is blackout in its value.lmpact assessment. unbounded nature of such an warranted beyond that already The Union of Concerned Scientists assessment. Based on public cornments, provided. The Commission is entitled to thought independent failures. in addition the Commission has revised the final inquire, and seek public comment on- to failures that lead to a station rule to modify the requirement for whether additional safety measures blackout should be included. One licensees to determine the maximum should be imposed where there is a individual stated that "both NRC reports coping capability. (See response to substantial increase in the os erall [NUREG-1109 and NUREG-1032] are public comments in subject number 9.)

protection of public health and safety completely deficient in that neither look Instead a coping assessment is required M sabotage." OCRE commented that on) for a specific duration.ne cost for fus ified in ie o t$s inere seismic events should also be suc a study is estimated to be from 70 E# d

• considered. to 100 percent higher than the original (C) With respect to safety estimates by the staff, and these revised 1 Cost Benefit Analysis and Whether improvements and overall nsk, different costs are used in the final value. impact f 50m Meen the "Substantiallocrease points of view were expressed. On one analysis, in the Ch erol/ Protection of the Public hand, NUMARC commented that, while ne staff revised its estimate of the Neo/th and Sofety" the nsk reduction might be large for a resource burden on NRC for review from Chairman Zech and Commisaloner limited number of plants, the nsk 120 to 175 person. hours per reactor. This Roberts requested comments on the reduction associated with the majority revision was based on technical review analysis of cost benefit, value impact, of plants will be small. Thus, as a required for other comparable NRC and safety impros ements and the general matter, the reductions in risk activities.

station blackout standing on the overall offered by the proposed rule constitute a (B) ne technical analyses performed risk (e g.,is the reduction of risk only a small percentage of the oveall risk, a for US! A-44 indicated that the small percentage of the overall risk, or is risk which is already small(and contribution to core damage frequency it a major component of an already acceptable). AIF stated that there is no from independent failures, in addition to small nsk?). Chairman Zech and standard by which to conclude that failures that must occur to get to a Commissioner Roberts were particularly "substantial additional protection will sta tion blackout, is low. Lik ewise, interested in specific comments be realized."

' results of USI A-44 studies and other assessing whether or not this proposal A different view was expressed by the probabilistic risk assessments have meets the "substantial increase in the Union of Concerned Scientists who shown that, for station blackout j overall protection of the public health stated that "station blackout la clearly a sequences, the contribution to core and safety * * '" threshold now major component of the totalrisk posed damage frequency from seismic events required by the backfit rule, by operatir3 nuclear plants. ne is low.

( Comments-(A) One of the major magnitude of the total risk is largely

.d Not all events can be analyzed on a comments by industry on the cost. unknowable due to the enormous benefit analysis was that the costs of probabilistic basis. Sabotage is an uncertainty which surrounds example. Even though sabotage was not implementing the proposed probabilistic assessments."

requirements have been underestimated.

explicitly considered in the staff's value.

Response-(A)1n order to adequately impact analy:Is. it is discussed in NUMARC and the Atomic Industrial respond to industry's comments above, NUREG-1100 under other Forum (AIF) commented that the cost the staff and NRC contractors reviewed considerations. nese considerations estimates for hardware modifications the cost estimates associated with support the conclusion that a station

, reported in NUREC/CR-3840, "Cost implementing the station blackout rule.

Analysis fer Potential Modifications To blackout rule will provide a substantial Based on this review, the estimated safety benefit.

Enhance the Ability of a Nuclear Plant To Endure Station Blackout," were too costs for hardware modifications were (C) ne revised value. impact analysis 4 reviewed and are in the range of from 20 performed for the resolution of USI A-44

E l

23208 Federal Register / Vol. 53, No.119 / Tuesday, June 21, 1988 / Rules and Regulations indicates that there are substantial plants, in fact, they said, "The French 5. The Needfor Ceneric Rulemoking benefits in terms of reduced core approach to station blackout does not 1 damage frequency and reduced risk to appear to depart significantly from Comments-Five letters from the the public that result from the station current regulatory approaches in the nuclear industry commented that ,

blackout rule, and the costs are U.S." Similarly, AIF stated,"The sme rulemabs b n t mcenary to warranted in light of these benefits. The assertions of extensive station blackout res Ive the station blackout issue. Their best estimate for the overall value- coping capability at foreign (notably nasons for W: fuue wm as foHows: l impact ratio is 2.400 person-tem per European) nuclear power plants are not A generic rulemaking is inappropriate since million dollars. Even if those plants with sufficiently substantiated % serve as the h:storic number of sites empenencing a the highest risk (and therefore the even part of the bask ,or the proposed Ion of an offsite pownis smansnas greatest risk reductiori) were not requirements," W'U"I considered, the value impact ratio for

• the remaining plants is still favorable uree other letters (Union of handYof."planY, Y[c"ba e nd does i Concerned Scientists. OCRE, and not need to be resolved by genene (i.e., about 1,500 person rem per million Illinois Department of Nuclear Safety) rulemakmg. Each plant has uruque dollars). supported the NRC rulemaking to probabihty for a loss.of. power egent based Analyses reported in NUREG-1150 require all plants to be able to cope with on transmission system. location of plant.

"Reactor Risk Reference Document" a station brackout, but urged the and onsite pow er systems (Duquesne Laght)

(draft issued for comment in February l 1987),' indicate that station blackout is Commissioit to go beyond the proposed The Commission need not pursue generic 1 rule. The Illinois Department of Nuclear rulemaking in order to resolve a non.genenc '

a dominant risk contributor to overall Safety stated that- issue. In the proposed station blackout rule.

residual risk for most of the six plants the number of plants of concem ie i analyzed. These results support the The goal of holding the expected frequency acknowledged to be luruled. (NUMARCl t comment by the Union of Concerned of Stahon blackout has been found not to be a '

percore damage reactor. from year is not stationstnrigent sufficiently blackout to to".

generic issue. Station blackout nsk is plant Scientists,in response to the With relatively modest modificahens to the Commissioner s request for comments spec:fic and. according to the staffe own proposed rule. a frequency of to"appears anal > ses. the proposal requirements are on this subject. achievable at reasonable cost. Specifically, expected to result in modicauoris ai no

( Whes.'.erSRCShouldRequire the rule should require no less than to hours more than a few facilities. if at any. Requiring Substantial /~provements in Safe. ty tbat d ' # h ' "* "I P' 'I '"* d I "IY ' !I I' C'" 8 ""d "'

• k ' ""* h ' '"'I) ' "

Go Beyond TMse Proposedin this four or eight hours in the proposed rule. In the under the provisions of the proposed rules esent of a blackout. when only a small group of plants may has e Commissioner Asselstine requested Response-The staff agrees with * ""d I "* ' d i' I * *"'" " ' PP'*P " ' '

industry's comments that foreign #

comments on whether the NRC should re uire substantialimprovements in countries may have vahd reasons for Response-ne Commission believes k" imposing requirements that differ from that a rule is appropriate to ensure that I ke the e be ng ac m ished in son r exceed those in the U.S. For example, station blackout is addressed at all other countries, which can be achieved it appears that there is a higher nuclear power plants. The plant. specific i h go yond frequency of losses of offsite power in features that contribute to n,sk for asonablejos p, , n 1 , France than in the U.S. His experience, station blackout (e g, diesel enerator Comments-NRC received eight al ng with French safety objectives, led configuration, probability of oss of letters that included comments on this the French to design their new standard offsite power) are considered by the subject. Five of these were from the nuclear power plants to be able to cope staffin the station blackout regulatory nuclear industry, none of which felt that w1th a very long duration station guide to determine an acceptable copmg the approach to station blackout taken S* duration for each plant. Even though not in European countries should be used to French safety" up toand approach three theirdays).

station The all sites have experienced a loss of ,

f ft i ha blackout design features are offsite power, there is not sufficient e3 nd he reposek The sin documented in NUREG-1206. "Analysis assurance that such events would not f French (Paluel) Pressurized Water {

justification for industry's argument is occur in the future. Since nistone that foreign countries may have reasons Reactor Due Muencu,, Compared to expenence has shown that a totalloss for req' tiring activities that differ from, Current U.S. PWR Designs, June 1986. of offsite power occurs about once every or exceed, those in the U.S. For example. The Commission believes that the 10 site years, and many nuclear plants staff has adequately considered foreign have operated for less than to years. it Washington Public Power Supply Systems (WPPSS) commented. "It is not approaches in preventing core melt from is not surprising that sorne plants have apparent that the details of U.S. grid station blackout in developing the experienced a loss of offsite power stabilities and onsite power reliabihties resolution of USI A-44 Although the while others have not. l are substantially similar enough to those rule requires plants to be able to cope Even though it is likely that many l found abroad to warrant a simple with station blackout for a specific plants will not need hardware cdoption of these [ European] measures." duration, that duration is not specified modifications to comply with the rule.

In another comment from industry on in the rule. Guldance to determine an the assessment of station blackout this subject. NUMARC stated that there acceptable duration is included in coping capability for a specific duration are several reasons why many of the Regulatory Guide 1.155. nis guidance andimplementation of associated features for coping with a station should apply to most plants, but if there procedures will affect a safety benefit blackout in new French nuclear power were adequate justification, different for all plants. The "limited number of plants may already exist at most U.S. requirements (either more or less plants of concern"in NUMARC's letter stringent than the regulatory guide) refers to those plants having the highest could be applied to specific plants. The risk from station blackout (i.e., those

> Yono rNorm.EppdYmi.Ts use of alternate ac sources provides a that would need hardware ,

meene Resvistory conum e weibraam oc means to achieve further incremental modifications). Without a plant. specific nu decreases in core melt frequency. assessment, these plants can not be

Federal Register / Vol. S3, No.119 / Tuesday, June 3L 1988 / Rules and Regulations 23209 identified. Even excluding these plants diesel generators, gas turbines, or term research can be taken into from consideration the staffs analysis nearby "black start" se power sources. account." They based this statement on has shown that the improvements in

• Extremely reliable offsite power safety associated with the rule are the premise that if the consequences supplies because of multiple right of- used in the staffs value. impact analy:Is consistent with backfit considerations ways or underground feeders to bac.k up were reduced by a fsctor of 10. none of

! set forth in i 50.109, above ground transmission lines.

the alternatives would be feasible.

6. Applicability of the Proposedf 50.63

• Dedicated shutdown systems and The Union of Concerned Scientists to Specific Plants associated diesel generators to meet the expressed a different point of view in fire protection requirements of Appendix R to 10 CFR Part 50 their letter which said "* *

• available Comments-Tour letters included evidence indicates that the

' comments or questions regarding the

• Common or shared systems consequences of an accident involving applicability of the rule to specific between two units at multbunit sites station blackout may be even worse plants. For example, does the rule apply such as direct current (de) power.

to high. temperature gas. cooled reactors auxiliary feedwater, or diesel than those estimated either in WASH-generetors. 1400 or the NRC's more recent studies."

(HTGR) (i.e., Fort St. Vrain)? What Response-NRC has had an extensive I about TMI-2 or plants that are near Response-The analyses performed completion but will not have an for US! A-44 clearly show that plant- research effort underway since about operating license prior to the specifig features do affect the nsk from 1981 to evaluate severe accident source statiorrblackout, and the station terms.The staff has reviewed the results amendment's effective date? Houston Power and Ughting Company wrote: blackout regulatory guide takes this into of this research to take into account the public comments received on this Proposed Section 50 63 provides schedular account in providing guidance on different acceptable coping dura wns subject. Since there is still a Ireat deal guidance farimplementmg station blackout- of uncertainty regarding source t?rms depending on the most signincant o(

related mod &caticns on plants that already and associated consequences. the staff hold operatirg bcensees or will be bcensed to these featurn. Those plants with operste prior to the effectn e date of the extremely reliable offsite and onsite ac revised its value impact analysis for USI  !

amendment. Plar.ts who reay be NTOL's power supplies need only have a very A-44 considering a range of estimates I lnear. term operating hcensej but will not be short (e g.,2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />) coping duration to be for consequences of a station blackout. l licensed pnor to the amendment's effectne acceptable. Plants that has e a dedicated The NRC research on severe accident I date should be accorded the same shutdown system with its own source terms has resulted in the I comphance penod under parts (c) and (d) of independent power supply could take development of significant new i this section. Otherwise this proposed rule i credit for this system to cope with a analytical tools by NRC contractors, as  ;

could be interpreted to trnply that plants not discussed in NUREG-0958.

heensed pnor to the effectne amendment station blackout The final rule and l date mast comply wah the ru!e and make all Regyjator). Guid'e 1.155 has.e been "Reassessment of the Technical Bases necessary modications pnor to recening an clarified to give credit for alternate a for Est! mating Source Terms." july 1988.

O t. loperatir.g Lcensej The ru!e sheuld be power supplies (see response to subject The analytical methods developed, generally referred to as the Source Term c d ed o rece e an Lw a short herefore, the Commission believes Code Package (STCP). have been used time fo!!owing erplernentation of th;s rule. that for almost all sites, plant. specific to analyze a number of severe accident differences have been adequatel aquences for On nfuence plants, Response-Rather than identifying specific plants for which the rule does accounted for in the resolution ofUSlnamely: Peach Bottom. a BWR Mark I A-44. but the door is open to licensees design: Sequoyah, a PWR ice condensen not apply 150 63(a) specifies when it does apply (i e., "each light. water- who believe their plants have additional Surry, a PWR with a sub.atmosp)eric cooled nuclear power plant licensed to capability that should be considered by containment; Grand Culf, a BWR with a operate"). Smce Fort St. Vrain is an the staffin demonstrating compliance Mark 111 containment; and Zion, a PWR with the rule' with a large dry containment (NUREG-HrGR. the generic rule would not apply. 1150,"Reactor Risk Reference Station blackout will be considered 8. The Source Term Used To Estimate individaally for that plant based on its Consequences Document." Draft for Comment.

February 1987).

unique dcsign. Since TMI-2 is not licensed to operate, likewise the rule Comments-NUMARC and others in The results of these analyses show the industry commented that the that releases from station blackout would not apply to that plant. Any plant consequences of offsite releases that licensed to operate after the date the sequences can be expected to vary rule becomes effective will comply with would result from a station blackout significantly depending upon the plant event are overestimated, and new and the specific sequence. Although the same 270-day schedule for information submittal applied to plants source term information would lead to generalizations are difficult, it appears the prediction of much lower that calculauons using the STCP yield previously licensed. This affords NTOLs consequences for this event. Several the same compliance features as plants release fractions for most of the already licensed to operate- commenters felt that the approach taken sequences range from about one third of by the staff to estimate consequences of an SST1 release (for the case of Surry, I

1. Plant Specific reatures and a station blackout event was improper- without condensetlon) to roughly one Capabihties decrea:Ing by a factor of three the order of m gnitude less than this, estimated consequences of the siting However, the uncertainties in our CommentJ-A number of utilities present understanding also do not described plant. specific features and source term (SSTI) from NUREG/CR-2723 "Eatimates of the Financial preclude the possibility of a large capabilities that reduced the risk posed by a station blackout event compared to Consequences of Nuclear Power Reactor release, approaching that of the SST)

Accidents" (September 1982), estimate, the staffs analysis. Examples of such AIF felt that "implementation of any features are given below. To determir.e the consequences to requirements resulting from the terms of person. rem, given the above

• Availability of alternate, resolution of USI A-44 should be range of release fractions, data take, independent ac power sources such as deferred until the results of the source from NUREC/CR-2723 indicate that the I

23210 Federal Register / Vol. 53, No.119 / Tuesday. June 21, 1988 / Rules and Regulations variations in person rem associated c plant can cope with a station blackout with releases of magnitude SST1, SST2 would go beyond the coping analysis for and SST3 are virtually identical to the ar2 not well defined and could a specified duration and recovery from potentially be unbounded. nese variations in latent cancer fatalities for station blackout. Therefore, the rule and the same three releases. Hence, the comments focused on two main points, regulatory guide have been revised estimated change in latent cancer First, the proposed rule required plants accordingly to delete the requirement for fatalities with release fractions provides to determine the maximum duration licensees the to determine a plant's plant could cope with a station blackout, a reliable indication of change in maxirnum coping capabihty.

person. rem as well. yet the draft regulatory guide included With regard to the comments on Table 10 in NVREC/CR-2723 presents specific guidance on acceptable copin8assessments to determine equipment durations (e g 4 or 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />).

variations in estimated latent cancer Determining the maximum duration, operability during a station blackout the fatalities associated with changes in staff feels strongly that such rather than assessing the plant's SST1 release fractions (for all elements capability for a spectfic acceptable assessments are necessary to determine except noble gases). This table shows a plant's response to station blackout.

duration, could be an open ended i that a release fraction of one third of an requirement. Along these lines- By deleting the requirement to determine

~

SST1 release would teld a value of NUMARC stated: a plant's "maximum" coping capability, about 50 percent of e latent cancer fatalities (and person rem) of an SST1 Unless the required co the assessment of equipment operability demonstration ]

release. Similarly, a release fraction of is specificauy bounded bh' eerly stated would not be as costly as assumed by induttry. Guidance on acceptable coping one third of an SST1 release would yield definitions, assumptions. and criteria there assessments is provided in the station an estimated person rem of about 15 could conceivably be hundreds of supporting special effects analyses which licensees may blackout regulato percent of that associated with an SST1 have to consider as a result of the exerose of guidelines uste gtogects eva,ry og guide.

joss Also.

release. Consequently, for value. impact d2scredon by individual staff reviewers. ,

calculations, the staff estimated the Under the rule as proposed. heensees cannot of ventila tion under station blackout a range o7 consequences o7 station conditions are provided in Appendix E ascertain the ultunate requirements they wdi be expected a meet (includma the potential of NHiARC-8700."Guidelines and to 0 5' t 5 t e es imated p son- N'd " Technical Bases for hMtARC rem of an SST1 release. As noted, the

.N,"co"r'np anc 'H nud m mahl truuatives Addressing Stauon Blackout original value. impact analysis was at Light W,ater Reactors., These efforts Second. industry also commented on based on 0.3 times the estimated person- the potential open-endedness of provide additional definitions, criteria.

rem of an SST1 release. and standards for licensees' analyses to determine the operabihty of With regard to a possible delay in the equipment in environmental conditions assessments of equipment operability resolution of US! A-44 until"better" without the need for "presenptise resulting from a station blackout (e g-regulations" by NRC.

source terms become available. key without heating. ventilation and air considerations appear to be when better conditioning). Unless these analyses in order to further evaluate industry's source terms are likely to become were well defined, industry felt the comments on this subject. NRC available and to what degree , talyses could be much more costly requested Sandia National Laboratories uncertainties in phenomenology as well than estimated by the staff. However, to identify specifb tesks r:ecessary to as differences between investigators NUMARC made the following statement determine operability of equipment will be resolved. Although research on relatirq to the need for detailed during a stauon blackout and to source terms is expected to continue presenptive requirements by NBC that estimate the cost to perform these tasks.

well into the future, improvements in our appears to contradict their earlier Results of this study were used in the knowledge are expected to be largely s ta tement. revised value impact analysis performed evolutionary beyond this point,in that the major phenomena appear to have W po'nt * *

• is not that regulations must for this issue ("Equ'pment Operability be presenptive their very nature During Station Blackout Event."

been accounted for, at least in a first. Prescr'ptne re ations, which outhne in NUREC/CR-4942).

order fashion. both in NRC as well as detail exactly hat steps are required by industry models. Resolution and hC'". sees to satisfy a proposed regulation. 20. Acceptoble Duration for Coping with of th are, m many instances, unnecessary and o Station BlacAout od so benef l pr ed * "" *P "" ##""

experiments and analytical models that *****'"I' Response-With regard to the differing views were directed at are likely to become available gradually. proposed requirement that each plant guidance in the draft regulatory guide on For these reasons, significantly better determine its maximum duration for acceptable station blackout coping source terms than those presently coping with station blackout, the staff durations in order for plants to comply evallable are likely to be forthcoming agrees with the industry comtnents. First with the proposed rule.

enly after a number of years. Since the range of severe accident source terme of all,it would be difficult to adequately Washington Public Power Supply and consequences sui define "maximum duration"in this commented that "it should be possible estimating station ckout bla'tgested sequencesabove is from sensa. Second. if licensees determine the.t their plants can cope with a ststion for certain utilities to demonstrate (an sufficiently broad to cover likely acceptablej aero hour blackout." One blackout for a specified duration and  ;

improvements in source term individual recommended "that a 30 restore ac power through an accep'able miaute period be a margin, and that no ,

knowledge. the resolution of USl A.44 coping analysis, the additional safety duration under 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> be accepted by shculd not be delayed, benefit gained from simply the the staff." NucleDyne Engineering

9. Specificity on the Extent o/ Required knowledge that a longer, or "maximum Copms Studies duration." coping duration exists is commented that "advanced reactors should require the capability to safely small. Third, the costs for assessing Comments--Severalletters by withstand a station blackout of atleast dustry expressed concern that the "maximum duration" will be higher 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />." and the Illinois Department of

.udies necessary to demonstrate that a since more extensive analyses will be Nuclear Safety wrote that "the rule required to analyze a transient which should require no tess than 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br />

Federal Register / Vol. 53, No. li9 / Tuesday. June 21, 1988 / Rules and Regulations 23211 decay heat removal capability instead of approach taken in Itbe proposed resolution). to plant.eentered events, and a slight only 4 or 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />." however, wiu not permit taking credit for the improvement in average diesel generator Response-Although diverse same d esel engine when used as a generator reliability frTam 1976 through 1983. These comments were received on this subject, though the actuai rehabihty for the machine is the same. (Toledo Edmon) factors have been taken into account in none provided supporting analysis or the staffs analyses and the resolution of information to back up the opinions Response-%e proposed regulation US! A-44. However, data also expressed. However, the staff did did not intend to ignore the alternative demonstrate that then are practical reanalyze the esumated nsk from of adding additional power sources or limits on ac power reliability, and the station blackout events for different taking credit for such sources if they defense in-depth approach of being able plant and site related characteristics already exist For example, as specified to cope with a station blackout is and revised its guidance on acceptable in the regulatory guide,if a licensee warranted.

coping duration accordingly based on a added an emergency diesel generator to l soal oflirniting the average contribution one ofits plants that had adrdmum # 8ho .

to core damage from stauon blackout to g ,,ro es e n uhi Unh redundancy in the onsite emergency ac about 10

• per reactor year. Most plants power system, the acceptable stauon gj'#8

, would still need a 4- or 8-hour coping blackout coping duration could be Commeau-Severallettats from j capabibly. nose few phnts with the reduced For some plants. however, industry stated that some planta with j most redundant onsite emergency ac addmg a diesel generator would not two anits on a site have the capabihty to power system, coincident with result fp a reduction in the acceptable crossue electrical buses between units significantly lower than average coping duration, and the point made by and therefore have improved flexibibly l expecsed frequency ofloss of offsite Toledo Edison is a valid one. The rule in providing ac power. Since the power, would need only a 2. hour and regulatory guide have been revised magnitude of the electricalloads capabdrty to be acceptable. Any plant to clarify that alternate ac power necessary to provide core coohng during with minimum redandancy in the onsite sources are given credit to cope with a a station blackout is significantly less emergency oc power syslem coincident station blackout provided that certain than that required for a design basis with now rebabihty and a significantly criteria are met (e.g.. independence, accident,it cou!d be possible to provide higher than average expected frequency redundancy, high reliabihty, ac power to both units at the site ueing of loss of offsite power would need to maintenance, and testingl- only a single diesel generator.

substanually improve its ac power reliability or be able to cope with a 12 Trends on the Re/iobility o/AC Response-The proposed rule and station blackout for 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br />.

ppy,fg,y,c,, draft regidatory guide do not prohibit the approach discussed above. lf Ommenl3- 'UtT* DC U

!!. Credit for Alternate or Diverse AC bcensus enn desnonstrata that such p g , comments on the reliability of ac power crosstia capability exista, procedures sources. Four letters from industry felt at in place to accomplish the crosstie Comments-Ten letters from the that improved ac power reliability utility industry commented that more should be factored into the staff s and shed nonessentialloads (if credit should be aflowed for the necessary), and no NRC regulations are technical analysis. F.tamples of these availability of alternate power sourtes violated (such as separation, minimum such as onsite gas turbines. The comments include the followin& redundancy, and independence), then comments below represent the trtdities' . .

• the requency of loss of offstte power credit would be given for this capabflity actmties has been decnaming * *

• as shown in Regulatory Calde 1.155 (i e.,

viewpoint.

(Wuh;nr.on Pi.blac powee Supply Systemh reduced acceptable station blackout The statwo bhcient rule sbec!d be * *

• offsite pewas avadabety in th*

absence of rega!auon has signir.cantly coping durations for greeter diesel clanCed to nuow cre&i for dnerse and very rehable offsite power sourtes or Lverse and improved over the past decade. (Southem generator redundancy).

very rebable onsite electncal sences ton. CaMomte Meon Compan#

(Public Service Company of Colo; ado) fNUREC/Cb4W) * *

• shows an M Mcotion of 6e Defm/tions of ne ophon of prending an adthonal Station BlocAout and Diese/ Generator improvement in chesel generstor nhabihty raffuf,,

alternate source of ac power is ehminated by oser that shown h the earlier document (NUREC/CR-2989)ICeneral Electnck and in this approach can bes)t be anderstood TwicaDy theby[the proposed rehabiUty tesolunonfrom of oosite power .Comments--(A)

De theinconsistency utility industry recommanded nice commenters considering an example at a secene owdear systems increases during the first few years power statiert (Toledo Edrson) foUowing startup.(Culf Statee Utahtaes) that the definition of station blac.kout in if the beansee were to provsde en l 50.2 should be clarified to exclude ac additionsl independence dassel senasa tor ne lilinois Department of Noclear power from the station batteries through capab'e of pron Safety, on the other hand. fett that inverters. nis source of ac power from the necessary ac powe' potential vulnerabilities effl! exist in the station batteries would be avsflable ould 11 required to ithstand a e's's t 4 onsite emergency ac power systems, and in the event of a loss of both the offsite bourt without ac power. ney would reech e licensees should demonstrate that they and onstte emergency ac power pontces no cnd2t for the add honal diesel genera:or have taken steps to reduce the (i.e. diesel generators).

to the coptog analysis. tf the ucensee were to probability of loss of ac power. (B) Several from tnduetry commented use that sarne diesel engine so power a Response-ne staff and its charging pump. eyes though te woehl be of that the definition of diesel generstar contractors have extensively analyzed failure shou}d be clarified, particularly less aisnificance ta adesahoa et reachoe core the ladustry experience and trends in oc with respect to the treatment of short-d* **88 * *^ th* d***l 8'n*3*$or **

power reliability es documented in term failures that can be recovered

$$"jd[ed Ed ' Pi 8** NUREG-1032. NUREC/CR-2989. quickly. Sargent and I, undy Enghteers o)

Since a diesel powered ch . .ng pump will NUREG/CA-397., and NUREC/CR- commented that-not provide for equipment los flexhlity. M.Trenda have shown that two j bghtirs ventilation. kerrumemation. etc It h aspects of ac power reliability have A deficution of failure on demand for obvicesty oflower enlue then an additional emergency d!uel generators needs to be improved somewhat-the reduced provided. Under the context of a station source of ac power. no fixed category frequency oflosses of offsite power due blackout. e diesel generator wtrich fefis to

l l

23212 Federal Register / Vol. 53, No.119 / Tuesday, June 21, 1988 / Rules and Regulations

=

start automatically upon detection of an 16. TechnicalComments on NUREG- Coolant Pump Seal Failures). Other offsite powerloss, but is successfully started JM2 manually from the main control room or fmm related issues mentioned in the public the local control panel should not be C ^ comments were A-30, Adequacy of g I"ydd;lI

, d n o comments Safety.Related DC Power Supplies, and considered a failure on demand.

bry guide, several ietters implementation of safe shutdown Response-(A)The staff a rees with contained comments on the staff's draft facilities to meet the fire protection comment A and revised the efinition of technical report. NUREG-1032, requirements of Appendix R.

station blackout accordingly. "Evaluation of Station Blackout Response-The question that needs to (B) Based on actual experience Accidents at Nuclear Power Plants." be addressed is should a requirement  ;

failures of diesel generators to start due Response-NUREG-1032 was issued be imposed now to reduce risk, or ,

to failures in the auto start system make in draft form for public comment in May should it be post ned until re at d - l l

up les: than 20 percent of all diesel 1985 (50 FR 24332). The comments af s ' i" generator failures. Therefore, received were reviewed and considered n% d h6 I

l discounting these failures would not by the staff and resulted in a re- substantial delays, thereby not resolving es j have a significant impact on overall evaluation of the technical analysis.

diesel generator reliability statistics. Details of the specific comments and f,

a n n;c a7etyl , co ide ed t e o$ut$n <

However, the staff agrees in principle responsesare not presented here. of USI A44 in light of the related issues l with comment B and has clanfied the Rather, NUREG-1032 was revised mentigned in the comments. Although station blackout regulatory guide so that extensively over the past year to a e ified a epa e auto start failures of diesel generators address the public comments. In gereral, (s need not be counted in determining the the overaU conclusions on the risk from in a well established regram that failure rate if the diesel generator is station blackout events did not change coordinates a re a issues.

capable of being started manually significantly as a result of the discussion of the most relevant issues is immediately after it does not start reanalysis. One of the major changes presented below. (Additiona automaticall resulting from the reanalysis was a information is provided in NUREG-1109.

revision to the definitions of plant "Regulatory Analysis for the Resolution M. Specificity and Clarificction of characteristics, especially the clustering of Unresolved SafetyIssue A44. Station Requirements of plants into site and weather related Bla ckout.")

Comments-Public comments were groups (Appendix A in NUREG-1032). Resolution of USl A-45 will occur m.

received regarding the specificity and These changes are rcflected in revisions some time following issuance of i e clarification of the proposed rule and to the guidance in the station blackout station blackout rule (150 63) and after draft regulatory guide. These ranged regulatory guide to determine plant. plant specific station blackout coping from general tc specific comments as the fic acc plable station blackout at ns h b p med by following two excerpts indicate: gefng p . BO Irduauve 5. utilizing guidelines provided We are concemed that. it the proposed rule 17. Relationship of USl A-44 to Other in NUMARC-8700. Further, the is adopted. the staff will promulgate NRC Ceneric issues resoluuon of USI A-45is expected to be regulatory guidance entens which will be Comments-The major public highly plant specific and focused on loss untenhstic and excessive.1 e.. compoundina comment regarding the relationship of of decay heat removal considerations the event with other accidents. impoung USl A-44 to other NRC generic safety from other causes beyond station passive failure entena, applying seismic, enstronmental quahfication and othe' issues was that the proposed rule may blackout. Uhlization will be made of A-quahf; cations to equiprnent that could not be necessary or should be +4 evaluations (as applicable) and any otherwise be used in response to such an postponed because of ongoing work to plant equipment modification needs recolve related generic issues. Some identified from A-45 will be carefully esent.etc.(Maine Yariee Atomic Power comments were generalin nature such evaluated to maximize effective use of fin ons of P1 and P2 (in Table 3 of the

E# * "

draft Regulatory Guidel use frequency of aModa Mon Compay d exuernely severe weather and severe Promulgation of a fir.at station blackout Maintaining emergency diesel weather interchangeably, thus creating rulemaking at this time wdl unnecessanly generator reliabihty. the purpose of B-confusion in the definition. (Washington compbcate the finst resolution of related 56,is an integral part of the resolution of Public Supply System) genene technicalissue * * ' The NRC must USl A-44. However, the Cornmission deselop and implement a propam to believes that additional defense.in-Response--Some of the comments on coordinate the resolution of au power related depth will achieve a substantial this subject relate to other subhets generic issues pnor to finalizing any increest in protection to public health discussed elsewhere in this section. indJvidual proposed rule.

er d safety.

Some comments were quite specific AIF suggested that the while others were generalin nature or The resolution of G123 (reactor implementation of any requirements for coolant pump sealleakage) deals with expressed views that were not station blackout be deferred until the loss of reactor coolant system inventory substantiated with backup material. The requirements from USI A-45. Shutdown and associated degraded core staff has taken these comments into Decay Heat Removal Requirements, are conditions. USI A-44 deals with station consideration and revised and clarified  !

known and until the effect of source blackout induced effects, which result in the rule and regulatory guide term changes can be evaluated. loss of ac power, thereby impacting a accordingly. Addnional guidance is NUMARC mentioned specific broa der spectrum of plant equipment provided in NUMARC-8700 which has proposed and existing regulatory and safety related functions. Although t>een reviewed by the staff and requirements that should be considered '

the resolution of GI 23 will contnbute to referenced in the regulatory guide as because they coulu reduce the need for establishing a higher level of assurance providing a method the staff finds a station blackout rule (e g. B-56. Diesel that sealleakage will be minimized acceptable for necting the rule. Generator Rehability, and G123. Reactor (thereby minimizing the need for power

I Federal Rrgister / Vol. 53 No.119 / Tuesday. June 21, 1988 / Rules and Regulallons 23213 to replace water inventory losses over rnerit the conduct and submittal of a be modified after licensees have the station blackout duration and probabihstic assessment as part of determined an acceptable station recovtry phase), resolution of GI 23 by achievtag comphance of l 5043. The blackout copmg duration and evaluated itself will not addresa the broader scope Comtoission's experience also indicates their plant's response to a station of USl A-44 safety concerr,s. that probabibstic assessments are blackout of this darauon.

Some licensees have implemented resource intensive and can be of (B)The staff ag'ees mth the dedicatcd shutdown systems that are margmal utiht) if their only end result is comments related to operator actions independent of normal and emergency to delay rule cornphance. outside the control room, and the ac pwer to meet Appendix R

19. Pmeedures andOperator Actions ngulatory guide was revised requirements. If applicable. these Durin8 Station BlocAoul according4 features would be credited in the i resolution of USI A-44 by provung the Comments--(A) Several letiers from 20. Schedule Pmrisions in Prepoud I capability to cope with a atation industry commented that,in response to fSOS l blackout. Generic Letter 81-04. "Emergency Comments-Two letters contained I l Thus, the resolution of USl A-44 is Procedores and Training for Station coordinated with re'ated genene issues. comment: on the proposed schedule in I Blackout Events." dated February 21.

, and implementation of a f nal resolution 1381 utilities stready have procedores I 50.63. OCRE felt the scheduling l should not be delayed further. prov sions in the proposed rule were far in place to prepare plant operations for )

(Response to comments on the effect of too generous. One indtvidual '

station blackout events. Owners' groups source term changes is included in ,

have established generic guidance for recommended that the schedule be sub)ect number 8.) modined to reqalte licensees to rubmit.

, station blackout operating procedures ,

within 9 months of the date of the '

18. An Alternative o/ Plant. Specific for ycasees to tree in develeping plant.

spectic procedures. A representative of amendment. a list of modtfications along ProbabihsticAssessments with a proposed schedele to impt; ment the Professional Reactor Operator those modifications. (Accordiog to the 8[gge a fn!feu( tj i" S ciety c mmented that:

p ed A licasen would not have requirements in the rule, licensees Generic procedures are used by rnost  !

to submit a schedule for implementing should ue permitted to submit plant- operstmg facihties These procedures are not equipment modifications until a fter the specific evaluationa to demonstrate that the frequency of core damage from [$g'fpIr$tio s Ne'i d'u b i e$o" staff received nuly on gener+c procedum and has not and reviewed licensees' subminals on Mr phat s acceptaMe station blackout events is 10"per snen a reallock at wi at specific steps must station blackout duration.) 1 l

reactor year or lesa. In a similar vein. be taken Extrspolabon of these procedsres Response-The staff ag eed in part the suggest>on was made that NRC must be required Speofic matmenance with these comments. and the schedule should specify a target level of procadares s,ast be estableed and fouowed. was revised accordeg!y. Section reliabihty for ac power systems in order (B) Other comments on procedures 50 63(c)(1)(iii) now requires that to satisfy NRC's criteria for core damage related to the timehness of operator licensees rubmit within 9 months after frequency. A few licensees submitted actions. both inside and outside the the rule is issced a Itst of eqctprcent limited probabilistic assessments to control room. Houston Lrghting and mod:fications and a proposed schedule shew that for some plants station power suggested that: for implementing them. A final schedule blackout could have a very small would be developed after NRC has probabdity of severe consequences. 3 Response-The Commission does not gj,f$["n st: t d bIreMd to reviewed the beensers' submittal of rud. Conndersuon shciuld o' e g:ven to their plant's acceptable station blackout preclude bcensees from sobmittmg timel) operator acticns both insrce r and duration.

plant-specific probabilirtic assessments to support a deterrnination that station outside of rAe convohtom that * * */ eo

21. /odustry /nitioff res that credit can be taken for enstmg blackout would beve a very small eqwpinent that may riot have octuahon and probabdity for causing core damage, control from the controi room. Comments-In addition to coruments However, the requtrements of the rule on the proposed rule. NM1 ARC Ilhnois Power Company endorsed the following fh e inIUatives 8 raust be met. The Cosnmtseion would recommended that:

observe that the use of probabshatn to addresa the more important assessments was lunportant as knpot to , , , section CAs. !!em 3 a. of the coritnbotions to station blackout-pro regulat ry guide should be modified i

the regdatory decishW that t M unisty wal revww eev saeis) w.unai.a die sta= bisao., ruie " "he ,,,se e, ,ho.id be a. - ~ s + = =

a ,.se a i,,,n, and related guidance. As expressed in actuated and conced from th centrol **d O dd'H* h * **** 'I d *"

the Commission's Safety Goal Policy reo a. or tf other ewens of centrol are oght. hour site after esdrums p as owe, statement of August 1986 (51 FR 20044), reqmrod ta4, manual)=mpeg of coortroi ewcn avaitable. the utibry will take actions the Corazmasjon has acquired a logica a ru m=1 sparation of valveek it to redece the sWs) contnbemm w the reasonable degree of costfidence about should be demonaerstad that shaae ssepa can overall nsk of station blectout. Non.

the usefulness and value of probabilistic be carried out la a timely fashion, hardu are changu wt11 be made withm one assessments in assisting regulatory Aesponee-(A)l.Acensees anay take [, , '", og decisionmaking on complex safety credit for station blackout procedures issues. la short. rnch anaesansents are of already in place to comply with the value in complemtoting and focusing the atation blackout rule. However, for the

• more traditional and determuinatsc most part, these procedures were gjjg%T,,',,"[""

delense-in depth approechen On the ,,,,omance of a corms inunmat .. Provwed developed without having the benefit of in wtwJtc-s'on w9ch wie nt emed try letter other hand, any Ikenace imust dedde a nt spectbc maseea.nent to determine frem ! OPda int *4^me) s. 7 seem fus) *wd whether or not its planhopecific ac w r a plant could withstand a N"*e= susst A sery a eMabas ta rutac power configuration and othat related equipment are sufficiently unique to atation blackout for a spedfnc duration.

Therefore, these proceduise may need to oc.

E7,"j*[d./M$t'"'$ N N m ei

l 25214 Federal Register / Vol. 53, No.119 / Tuesday, June 21, 1988 / Rules and Regulations L Each utility willimplement procedures at each ofits site (s) for: additional radiological exposure to the

a. Coping with a station blackout event- general public or plant employees, and Radiation protection, Reactor siting

b. Restoration of ac power following a plant shutdown is not required so there enteria, Reporting and recordkeepLng >

requirements.

are no additional environmental impacts Prepanns the p nt fo severe weather as a result of the need for replacement For the reasom set out in the condshons (e 3, burncanes and tomadoes) to power. The environmental assessment preamble and under the authority of the reduce the hkehhood and conuquences of a Atomic Energy Act of 1954, as amended, loss of offsite power and to reduce the overall and finding of no significant impact on Reorganization Act of1974, the Energy risk of a station blackout event. which this determination is based are available for inspection and copying for as amended, and 5 U.S.C, $53, the NRC

3. F:ch utihty willif appheable, reduce or ehminate cold fast. starts of emergency diesel a fee at the NRC Public Document is adopting the following amendments to to Cm Part 50, generslors for testing through changes to Room.1717 H Street NW., Weshington, technical specifications or other appropriate DC. Single copies of the environmental assessment and the finding of no PART 50-DOMESTIC LICENSING Of 4 E ch ubbty willmonitor emergen ac power unavailability utilizing data utMties significant impact are available from Mr. FActLITIES AND UTILIZATION PRODUCTION Warren Minner., Office of Nucleat provide to INPO on a regular basis.

Regulatory Research, U.S. Nuclear 1. The authority citation for Part 50 is

5. Each utihty will assen the abihty ofita plant (s) to cope with a station blackout. Regulatory Commission, Washington, a' sed io mad as follows.-

Mants udhzing altemate ac power for station DC 20555, Telephone:(301) 492-7827 Authority: Seca. 101 103.104.105.161.162.

blackout response which can be shown by Paperwork Reductico Act Statement 183.1stL 189. 68 Sta t. 936,937. 938. 948. 953.

• test to be available to power the shutdown '

busses within to min;;tes of the onset of 954. 955. 968. as amended. sec. 234. as Stet This final rule amends informalion 1244. as amended (42 U S c. 2132. 2133. 2134.

stat on blackout do not need to perform any collection reSairements that are suolect 21n 22. 2232. 2233. 22n 22n 2282h sus.

coping assessment. Remaining alrema'e ac to the Paperwork Reduction Act of1980 201, as amended. 202. 206. 68 Stat.1242. a s plants will assess their abihty to cope for 1 (44 U.S C. 3501 et seq.). These hour. Plants not quhsing an ehemate ac amended.1244.1248 [42 U S C 5841. 5842.

requirements were approved by the 5846).

source will assess their abihty to cope for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. Factors idenufied wluch prevent Office of Management and Budget Secuon 50.7 also issued under Pub. L 95-demonstraung the capabihty to cope for the approval number 3150-0011. ect. sec.10. 92 Stat. 2951142 U S C 5851).

appropnate duration will be addressed Section mio alm issued under secs 101.185.

through hardware and/or procedarsi changes Regulatory Anal) slo sa Stat.936.955. as amended (42 U.S C 2131, so that saccessful demonstrobon is possible. The Commission haa prepated a 1235); sec 102. Pub. L 91-190. 83 Stat. 853 (42 US C 4312). Sections so 23 50 33. 255. a nd NUMARC previously opposed generic regulatory anal) sis on this final 256 also issued under sec.185. 6a Stat. 955 rulemaking and felt that the first four regulation. The analysis examines the (42 U.S C 2235). Sections 50 33a 50 554 and initiatives would resolve the station costs and benefits of the alternatives Appendix Q also issued under see 102. Pub.

blaekout issue. considered by the Commission. A copy Response-These five initiatives now of the regulatory analysis. NUREG-UO9 'IIons 50 3 nd 50. a so sue der Sec include many of the elements that are "Regulatory /Backfit Analysis for the sec 204. 88 Stat.1245 (42 U S C 5844).

Sections 50.58. 50 91, and 50 92 also issued included in the NRC resolution of USl Resolution of Unresolved Safety Issue A-44. The staff has followed up on the A-44. Station Blackout,"is available for under Pub. L 97-415. 96 Stat 2o73 (42 U.S C inspection and copying for a fee at the 2239) Section 50 78 also issued under sec.

NUMARC initiatives through a series of 122. 66 Stat. 939 (42 US C 2152). Sections meetings in 1966 through 1987. The result NRC Public Document Room.1717 H So esso et also issued under see 164. es Stat.

has been the development of NIStARC- Street NW., Washington. DC 20555. 954. as amended (42 U S C 22341. Section 8700 which provides guidelines and Regulatory Flexibility Certification 50.103 also issued under sec.106. 6a Sta t. 9R criteria acceptable to the staff. The as amended (42 U S C 2138). Appendix F also As required by .he Regulatory lasued under sec.187,68 Sta t. 955 (42 US C procedures in NUMARC-4700 have been Flexibihty Act (5 U.S C. 605(b)). the referenced in Regulatory Guide 1.155 a:

providing guidance acceptable to the Comminsion certifies that this rule does 22f the purposes of sec 223 ea Stat.

osa staff for meeting the requirements of the not have a significant economic impact amended (42 U.S C 2273). Il mio (a). (b)..

on a substantial number of small and (c). 50 +4. 50 46. 50 48. 50 54, and 50 8o(41 rule. Table 1 in Regulatory Guide 1.155 are tesued under sec. telb. se Stat. 94a. as provides a cross. reference to NUMARC- entitjes. The rule requires that nuclear power plants be able to withstand a amev d (42 US C 22011b)): il 5010 (b) a nd 8700 and notes where the regulatory (c), and 50 54 are issued under see leti. es guide takes precedence. NUMARC's totalloss of ac power for a specified Stat 949. as amended 142 U S c. 220t(ill. and previous concerns have been addressed time duration and maintain reactor core ll 50 9. 50 55(el. 50 5@l. mm m71. m72, coohng during that period. These 50.73 and m?s are issued under sec. leto, se

' in the deselopment of Regulatory Guide 1.155 and NUMARC-4700, facilities are hcensed under the Stat. 9m as amended (42 US C 2201(oll.

Finding of No Significant Environmental CFR Part 50. The compa)nies that 2. Inownprovisions i 50.2, definitions ofof Ii 50.21(b "alternate ae and 50 act aF4 source", "safe shutdown" and "sta tion these facilities do not fall within the blackout" are added in the al The Commission has determined scope of "small entities" as set forth in sequence to read as follows: phabetical under the National Environmental Policy the Regulatory Flexibility Act or the Act of 1969, as emended, and the small business size standstds set forth W2

• Mens.

Commission's rules in Subpart A of to in regulations issued by the Small * * * * ,

CFR part 51, that this rule is not a major121, Business Administration in 13 CFR Part "Alternate ac source" means an Federal action significantly affecting the alternating current (ac) power source quality of the human environment, and Ust of Subjects in 10 CFR Part 50 that is available to and located at or therefore, an environmentalimpact nearby a nuclear power plant and meets statement is not required. There are not Antitrust. Classified informa tion, Fire the following requirements:

any adverse environmentalimpacts as a prevention, Incorporation by reference, intergovernmental rela tions. Nu clea r (1)la connectable to but not normally result of the rule because there is no connected to the offsite or onsite power plants and reactors, Penalty, emergency ac power systems;

rederal R:ght;r / Vol. 53. No.119 / Tuesdby June 21. 1988 / Rules and Regulations 03215 (2) Has minirnu n potential for recover from a station blackout as sect 6n, and a propored schedule for common mode f ailure with offsite power de fined in 150.2. The specified station imp!cmentirg the stated modifications.

or the onsite emergency ac pow er blackout duration shall be based on the sources; (21 Alterna:e oc source:The alternate following factors: se pow er socce(s). as defined in i 50 2.

(3)is availuble in a timely rnanner (i)The redundancy of the onsite will constitate acceptable capMity to after the on:et of station blackout: and emergency a ; power sources: withstand station blackout presided an (4) Has sufficient capacity and (ii) The reliabil;ty of the onsite analysis ts pe: formed which reliability for operation of a!! s3 stems errergency ec power sources; required for coping with station dm.cnsvates that the plant has this liii! The expe:ted frequency ofloss of capability from onset of the staticir blar.kout and for the time requised to offs;te pow en and bring and maintain the plant in safe (iv) The probable tire needed to blackout unt:1 the altcmate oc sourcets) restore offsite power. and required shatdown equipment are shutdown (non design basis accident),

"Safe shutdown (non-design basis started and hned up to operate. The time (2) The reactor core.and associated j accident (non.DBA))" for station coolant, control, and protection systems. required for startup and abgnment of the alt, mote ac power source {s) and this e

blackout means bringing the plant to including station batteries and any other those shutdown conditions specified in necessary support systems. must equipment ehall be demonstrated by plant technical specifications as Hot provide sufficient capacity and i,,t. Alternate se source (s) serving a

. Standby or Hot Shutdown. as capability to ensure that the core is mahip!e unit site where onsite and appropnate containment emerFency se sources are not shared appropriate (plants have the option of b* oftween maintaining the RCS at normal C('

integn ole lty is maintained in the event a units must have, as a rninimum.

operating temperatures or at reduced station blackout for the specified tu capacity and capabihty for coping temperatures). duration. The capability for coping with wr.h a station blackout in any of the i tu ::s At sites where onsite emergency "Station blackout" means the a station b!ackout of specified duqtion shall be determmed by an appropnate ac sources are shared betwec n units, the completeloss of alternating current (acj electric power to the essential and coping analy sis. Utilities are expected to aDemete ac sourcels) must have the nonessential switchgear buses in a hue the baseline assurnptions. c.Tscity and capability as requ! red to nuclear power plant (i e, loss of offsite ana!yses, and related information used c nnte that all units can be brought to electric power sy stem concurrcnt with in their coping evalua tions ave!!hble for snd maintained in safe shutdow n (non.

turbine trip and unavailability of the NRC review, CDA) as defined in i 50.2. li the onsite emergency ac power system). (b) Limirofion of scope. Paragra ph (c) alternate ac source (s) meets the above Station blackout dees not include the of this section does not apply to those requirements and can be demonstrated loss of available ac power to buses fed plants licensed to operate prior to/uly h w W neuaMe to powet the by station batteries through inverters or 21. m if the capability to withstand shatdown buses within to minutes of the by alternate ac sources as defined in station blackout was specifically onset of station blackout then no coping analysis is required concur ent air e fai u e sign basis o ed g n as e a prowl l accident. At single unit sites, any consi e7a on f thefo ation e rgency ac pow r source (s)in excess ,(c)Implekentatim -(1)Information submitted in acconlance with pararaph o e nuro er requ to meet Submittel For each hght water cooled (c!!!! of this seetion. the Director. Office gl

'( nuclear bower plant beensed n or be re fuly 21.1933. the hcenser to of Nuclear Recctor Regulation. will operate not.f the beansee of the Directors lu e)for saf s u own on DBA) : assumed to be as ailable and shall subrnit the information defined conclusions regarding the adequacy of may esignated as an altemate below to the Director of the Ofhce of the propescd specified station b!ackout pow er source (s) presided the applicable Nuclear Reactor Regulation by Apri/ fr. duration. the proposed aquipment requirements are met. At multi-unit 19s For each li ht water cooled mod:ficatio .s ar.d procedures, and the sites, where the combination of nuclear power pfant beensed to operate propsed schedule for irnplementing the after the effective date of thin - procedures and modificatiens for he snu rd anc u me is amendment the beensee shall submit cornp!iance with pararaph (a) this for safe ahutdewn(non-DBA) f all the information dehned below to th. aection.

Director by 270 days after the date nf (!) /mplement A 'on Schedule: For ea ch I er a s m Y be us as alfernate hc m eissuance. Ight. water cooled nuclect power plant e ac power sources provided they meet (1) A proposed station blackr.ut bcensed to operate on or before June 21.

the applicable requirements. lf these duration to be used in determining 19M the licensee shell, within 30 de s complianca with paragreph (a)of this of the notificatien provided in f critena are not met station blackout section. Including a justification for the must be assumed on all the units. acccrdance with paragraph (c)(31 of this

' selection based on the four factors section, subrnit to the Director of the llo.s IAmended) identified in paragraph (a) of this Office of Nuclear Reactor Reguletion a

3. In 4 50.8 paragraph (b). insert the sectioru schedule corrmitment for impicmenting i

section nutnber 50.63 in numerical order (ii) A description of the procedures any equipment and associated in the list of section nurnbers. that wiD be implemented for station procedure modincations necessary to

4. A new 150.63 is added to read as blackout events for the duration meet the requirements of paragrcph (a) fouows: determined in parseraph (c)(1)(t) of this of this section.This submittal must section and for r 3ery therefrom: and include an explanation of the schedule I so.s3 t.oss of as enernating current PNf- (111) A iist of modifications to end a justification if the schedule doea equi 8

(a) Requirements. (1) Each light- 'any.pment necessaryand associated to meet procedures. if not provide for completion of the the requirements water-cooled nuclear power plant modifications within Iwo years of We a of paragraph (a) of this section. fer the notification provided in accordance with

, licensed to operate must be able to specified station blackout duration withstand for a specified duration and paragraph (c)(3) of this section. A final determined in paragraph (c)(1)(1) of this schedule for implementing modifications 1 _

-23216 Federal Register / Vd. 53, No.119 / Tuesd y, bne 21, 1988 / Rules and Regulations necessary to comply with the 2 requirements of paragraph (a rule is presented in NUREG-1100, =  %

section will be established by)of this

• Regulatory /Backfit Analyals for the reactor risk, in general, active systema the NRC Resolution of Unresolved Safety Isaoe reprired for contairunent heat removal staff in consultation and coordination are unavilable during station blackout. '

with the affected licensee. A44. Station Blackeut. The estimated Derefore, the offsite risk is higher from benefit froca implementing the station Dated at Rochelle. Maryland, this 134h day blackout rule le a reduction in the a core melt resulting from a station ollune 1988.

frequency of core damage per reactor, blackout than it is from many other For the Eclear Regulatory Commissa year due to station blackout and the accident scenarios.

smuell. CE gggc, , associated risk of offsite radioactive releases. The risk reduction for 100 Althougb there are licenting requirements and guidance directed at Backfit Analysis operating reactors is estimated to be provans reliable offsite and onsite ac 145.000 person tem and supports the power, experience hat shown that there Anoty sis and Determinot. ion That the are practicallimitations in ensuring the Commission's conclusion that t SG63 teliability of oIfsite and onsite Ru/emoking To Ameid10 CFR Po.t.W pr vides a substantialimprovementin Concerning Station BlacAout Coc p//es the level of pubbe health and safety emergency ee power rystems. Potential With the BockhtRule 10 CHisais pr tecum w vulnerabilities to cornmen cause failurea The Comminion's existing regulations De cost for licenaces to comply, with associated with design. operatior:al, and establish requirements for the design the rule wesid vary depending oa the environmental factors can a ffect ac and testing of onsite and offsite existing capabrlity of each plant to cope power system reliabibty. For example, if elee'ricalpower srstems 110 CFR Part with a station blackout, as well as the potential common cause fa!!u.es of 50, Appendix A.GeneralDesign Criteria specified atation blackout duration for emergency diesel generstors exist 17 and 18). However, as operetrng that plant n in service. water or de power suppe(e.g-t experience has accumu?ated, the for bcensees1)(e to costs assesswocid be primarily the plant's systems , then the esumated com concerr hae arisen regarding (1 capability to cope with a station damage) frequency from station b!ulout reliabih)ty of both the offs (te andblackout. ocstte(2) to develop proceduees.13) events can increare significantly. Also, emergency ac power systems. These to improve 6esel geners tot reliability if even though recent data indicate that systems provide power for varioca the reliability falls below certain levels, the average emergency diesel generator safety systems. includm and (4) to retrofit plants with additional reliability has fmproved slightly smce decay heat removal arw)g reactor core components or systems, as necessary, to cootainment 1976. these data also show that diesel -

heat remotal which are essential formeet the requirements. generator failure rate during uriplanned preserving the integrit) of the reactor The estimated total cost for 100 demand (e.g., following a loss of offstte c:re and the contamment building. operating reacters to comply with the power) were higher than that during respectively. In numerocs instances resolution of U52 A44 is about 500 surveillance tests.

emergency diesel generators have failed million. The average coat per reactor ne estimated frequency ogcute to start and run during tests condocted would be armmd $600.000, ranging from from station blackout events is t operating plants. In addition, a $350.000,if only a station blariout damafy PNpoenal b de Mmy o ee Madng et Watn of stah umber of operating plants have assessment and procedures and training experienced a totallose of offsite are necessary, to a maximum of about blackout frequencies for this USl were electric power, and more such $4 million if substantial modifiestions based on actual operational experhnce occurrences are expected. Existing are needed, including requa hfication of with credit given for trends showing a regulations do not require e_sp!icitly that a diesel generator. redaction in the frequency oflosses of nuclear power plants be designed to The overall value. impact ratio, not offsite power resulting from plant.

withstand the loss of all ac power for including accident avoidance costs,is any specified period. about 2.400 person rem averted per centered events nis is assumed to bc 4 realistic Indicator of future performance.

This issue has been studnd by the million dollars. lf the net cost, which An argument can be msde that the staff as part of Unresolved Safety Issue includes the cost sayings from acddent future performance will be better then (USI) A44, "Station &ckout." Both avoidance (i.e the past For example, when problems deterministic and probabf!istic anal) sea onsite damage. cleanop and repair s and replacement power of following an accident), were used, the with the offsite power grid arise, they were performed to determine the timing are fixed and, therefore, grid reliability and consequences of various accident overall vahre. impact ratio would - should improse. On the other hand s3quences and toidentify the dominant improve significantly to about 6.100 power failures may become mon , s'id factors affecting the likehhood of core person tem averted per miDion dollars, .

fMquent because fewer plants are being mitt at cidents from station blaclout. These 5 aines, wh!ch exceed the $1.000/ built, and more power la being Although operational expedence shot a person-tem interim guidance provided transmitted among regions, thus placina thst the risk to public health and safety by the Coumission, suppart proceeding greater stress on transm!ssion lmes.

is not undue, these studies, which have with the implementation of 6 50.83.

ne preceding quantitative value. The factors discussed above support evaluated plant design features and site-dependent factors in detail, show that trnpact analysis was one of the factou tl a determination that additional blackout can be a significant contributor considered in evalua ting the rule, but defensa.In-depth provided by the abilPy other factors also played a part in the of plant to cope with station blackout to the overall residual risk. for a specific duration would provide Consequently, the CommissMn is decision.makir.g process. Proba bilistic amendmg its regulations to require that risk assessment (PRA) studies substantialincrease in the overall performed for this USL as well as same protection of the public health and plants be capable of withstandmg a safety, and the direct and indirect costs total loss of sc power for a specified plant specific PRAa, have shown that station blachut can be a significant of implementation are justified in view duration and to maintain reactor core of this increased protection. The moling during that petiod. contributor to core melt frequency, and,

't analysis of the benefits and costs with considera tion of containment Commission has considered how this failure, station blackout eventa can backfit should be prioritized and splementing the station blackout represent an important contributor to scheduled in light of other regulatory activities ongoing at operating nuclear

Feder:1 Register / Vol. 53. No.119 / Tuerdoy June 21. 1988 / Rules and Regulations 23217 I

t power plants. Station blackout warrants required by the licensee or applicant in significant increase in occupational a high proiorit) ranking based on both order to comple te the backfit, esposure is expected from operation its status as an "unresob ed safety and maintenance activities associated In order to ecmply with the resolution issue" and the results and conclusions c,f USl A-44. licensres willle requind with the rule. Equipment additions and reached in resching this issue. As noted to_. modifications contemplated do not in the irnplernentation section of the rule

• Maintain the rcliabil;ty of onsite nquire w rk in and around the reactor

! (150 63(c)(4)). the schedu!c for emergency ac powc r sources at or above eu lant systern and therefore are not e')ulpment rnodification (if needed to specified acceptatile rehability levels, eyected to rcsult m significant meet the requirements of the nile) shall + Develop procedures and training to r:,diatien esposure.

be estabbshed by the NRC staff in resto:e ac power using nearby powrr 5. Installation and continuing costs e

consulation and coordination with the sources if the emergency ac power associated with the backfit, including licensee. Modifications that cannot be system and the normal offsite power the cost of facility downtime or the cost schedule fJr Completion within two sources are unavilable, of construction delay.

years after NRC accepts the licensee's

• Detctmine the duration that the specified station blackout duration must plant should be able to withstcnd a For 100 operating reactors, the total be justified by the licensee. The NRC station blackout based on the factors estimated cost associated with the retains the authority to determine the specified in i 50.63 "Station Blackout. station blackout rule ranges from $4 to S94 million with a best estimate of $60 schedules for modifications. and R u{atory Guide 1.155. Station Bc million. This estimate breaks down as in addition. some foreign countries. I UU*C including France. Britisn. Sweden. f a allable, an alternate ac poveer source that meets specific criteria for sc Germany and Belgium have taken steps r,t, .m., ec c independence and capacity can be used rmee v*oa cos**

to reduce the risk from station blackout to cope with a station blackout.

events. These steps include addin8

• Evaluate the plant's actual Actw M, design features to enhance the rue. Best He tc=

capab;!ity to withstand and recover 'on capability of the plant to cope with a frem a station blackout. This evaluation station blackout for a subsNtial period includes: #"'P***

of time and/or adding redundani and diverse emergency ac power sources-

-Vcrifying the adequancy of st. tion battery pow er. condensate storage Eo*

• too t>eocut .. .- 25 40 to Analysis of 9 50.109(c) Facters i' "

[' r" destb'o" e ion. d * 'UO 'O '

1. Statement of the specific objectis es -Vuifying the operability of equipment 9,, mo, that the backfit is designed to achies e, needed to operate during a station caseer..._.. 10 25 a is blackout and the recovery from the The NRC staff has completed a review and evaluation of information des c!oped blackout for environmental conditions g.,%., ,

f a u 4 u

'* ' " **E""

since 1980 on Unresolved Safet) Issue ""..'los: of heating. ventilation, and "'***"

(1 e cace"n io coo. l (USI) A-44. Station Blackout. As a result air conditioning).

of these efforts, the NRC is amending to mae '

e Depending on the plant's eusting '* * - " " "

CFR Part 50 by adding a new ( 50 63, {

"Station Blackout." capabnity to cope with a ststion Tows -- eo 84 42 The objectise of the station blackout blackout. licensees may or may not need -

to backfit hardware modifications [e g.'

rule is to reduce the nsk of sesere adding battery capacity) to comply with 6. The potential safety impact of accidents associated with station ch.nges in plad or operational the rule. (See item 8 of this anal > sis for blackout. Specificall3. the rule requires additional discussion.) Licensees will be complexity. including the relationship to alllight. water c'ooled nuclear power required to have procedures and tra'n! g proposed and cxistir g regulatory plants to be able to cope with a station to cope with and te cover from a statien requirements.

blackout for a specified duration and to blackout. The rule requiring plants to be able to have procedures and training fnr such cope with a station blackout should not

e an event. A regulatory guide. to be

" " ""8 " d'

- p ;c a den alo a lease [g$p[ rat al e mplexity.

lasued along with the rule, provides an ,

acceptable method to determine the of radioactive material-I' related to several NRC generic programs

' station blackout duration for each plant. Implementation of the station and proposed and existing regulatory The duration 1:10 be determined for blackout rule will result in an estimated requirements as the following disettssion 4 each plant ba' sed on a comparison of the total risk reduction to the public ranging indicates.

3 todividual plant design with faetors that to 5 'h a o

have been identified as the main '0*(( , , per,soj4 ,Qc n. g,,,,.j,f,,y,3,3g,gj,,,jg,,,fof,7 Reliability 1

contributors to risk of core melt resulting from station blackou;. These 4. Potent!alimpact on radiological The resolution of USI A-44 includes a

. factors are (1) the redundancy of onsite regulatory guide on stdtion blackout that exposure of facility employees.

emergency ac power sources. (z) the spec fies the following guidance on For 100 operating reactors, ti:e d2esel generator reliability (Regulatory reliability of onsite emergency ac power estimated total reduction in sources. (3) the frequency ofloss of Guide 1.155. Sections C1.1. and C.1.2):

d occupational exposure resulting from The minimum eme ncy diesel generator offshe power, and (4) the probable time reduced core damage frequencies and (DC) relisbuay shou o be targeted at 095 l needed to restore offsite power, associated postaccident cleanup and per dernand for each EDG for plants in

2. General description of the actisity repair activities is 1.500 person rem. No emergency ac Groupe A. B and C and at 5

U

23258 .

Federal Redst:r / Vol. 53, No.119 / Tuesday, June'21,1968 / Rules and Regulations O er5 per demand for each EDC fot #ac ts in emergency ac Group D isee Table 4 Nsa USl A-45, Shutdown Decoy Heat be reevahrated be. fore any actual reliabGty levels will be considesed r.in. mum RemorclRequirements modifica tions are made so that any target reliabataes sad each p'ani should hase The overall objective of USJ A-45 is to contemplated design changes resulting an EDG reliabihty prq; ram contairdng the evajgate the adequacy of current pnncipal eternents. or thest e quiva'en t. licensing desfIU requirements to ensure frorn the resolution cl USl A-45 can be outlined in Regulatory Pusition 1.1 Plents considered at the sa.me trme.

that the nuclear power plants do not that select a tartet EDC reliabituy of o ws pose an unacceptaMe d as a resuh of Generic /ssue A-#, Adequacy of will use the bl@er icvel as ee tar 2*t in tbeitlailure to remove shutdown decay heat, Sofety.RelatedDCron er Supply The study ladudes an assessment of '

e re at of uns.te e=reency We analysis performed for USI A-44

{

alternative means of shutdown decay ac power sources abuuld be eoscred by a heat removal and of diverse "dedicated,, assutsed that a high level of de power 6, relmsbaty pres a:s desigred to meintain and systems for this purpose. Resuhs will system rehabibty won]d be maintained monitor the rehab:hty levd of ead power include proposed recommendations so thaa l1) de power system failures sourra over time for assarance thei the regarding the desirabdily of, and would not be a signi$ cant contributor to l selected rehabiliry levels av being 4Weved. losses of aD ac power and (2) should a I possible design requirements for, An EDG rehabbty peegram wild typicsity improvements kn existing s) stems of an station blackout ocur, the probabdity of be composed of the fo'towtr's elements er immediate dc power system failure alternativg dedicated decay beat actiwties (or the*t equivsteMT would be low, Whereas Geeeric tseue removal raethod.

1. tndrvidual EDG reinb@y hrrd I,wefs  !

The USI A-44 concern for man:ta.n ing A-30 focuses on enhancing bsitery consietent with the plant catepary and cepeng ad uate core cooling uDdet station ,,g gp g gg og gSg y ;,

duration se!ected frarn Tehte 1 blac out coodations can be considered a aimed at enauting adequate station

2. Survenanc4 test.r.4 ed rebb?.4 subset of the oserall A-45 issue. battery capacity in the event of a station memtormg pmg ems devg*ed to trad EDG perfoniance and to saport msnterance Howes er, there are significant bl&t of a p&d kh actnities. differences in scope between these tw o herefore, these two issues are i

3. A maintenan;c Wane rhet "inres Issues. USl A-44 deals with the c nsistent and compst;ble.

that the target CDG rehabit; is being probabdity ofloss of ac power, the capabihty to remot e decay heat t.tsing A re pro r,gr/oa preg m m achieved and th4t provides a cap #n: ty for fal;ure anal > s s and root.<a us" systerns that do not require ac power.

inns tgations- and the abihty to restore ac power in a Section 50.48 of 10 CFR Part 50 states that each operstmg nudear power plaol

4. An trJorna son and data cdNeu timely manner. USl A-45 deals with the system that senices the alereros of the must have a fire protection plan that overall reliabihty of the deray beat satisfies CDC 3. The fire protec11orr e ret a a e e a rernoval fonction in terms of response to features required to satisfy CDC 3 are transients, smaSbrea k loss-of. coolant l

y ;,,' st sere specified in Appenda R to 10 Cnt Part accidents, and special emergencies such  !

5. Identified respoesibl&s for tha saajar as fires, floods, seismic events, and 50. hey include certain provisions program elements and a rnanate me.;u sabota$ regarding alternative and dedicated osersight preg?am fa revien tr's rettabihry .Although the recommendat>cr.s that shutdown capabihty.To rneet these i

levels beir: acbes ed and aewr ng ' hat th, might result fro:n the resolution of USL provisions, some licensees have added, program is facties property A-15 are not yet final, some eculd affect or plan to add, improved capabdity to The resolution of B-56 win prou,de the station blackout capability, while restore power from offsite sources or specific guidance for use b) the staff or others would not. Recommendations onsite diesels for the shutdJwn system.

industry to review the adequacy of that invohe a new or improved cecay A few plants have insta!!ed a safe diesel generator rehabihty pregrxes heet recm al system that la ac power shutdown facihty for fire protection that dependent but that does not include its includu a argica pump powmd b

• consistent with the resolutron of USI A-

44. own dedicated ac power supply would its own independent se power sourcv). in have no effect on US! A-44. the event of a station blackout, this R d ' th neri hwe

" #" 21 Rmc 'or Coole.N Putrp a{t

'" system can provide rnakeup capa bihty at.ndepen e ay hed to the primary coofant eystem as well as Rcector coolant pump (RCP) seal removal system would have a very reactor coolant pump seal cochng. %is integrity is necessary for maintaining modert effect on USl A-44. could be a significant benefit in terms of primary s) stem inventory durin6 station Recomrnendations that involve an enhancing the ability of a plant to cope additional decay heat removal system blackout conditions. The e e tes of with its own ac power supply would with a staticn blackoct. Plants that hase core damage frequency for ' an added equipment to achieve alterneta blackout events for USl A-,4 ussaned have a si nificant efMet on USI A-44. safe shutdown in order to meet Such a ne;;w additional system would that RCPseals wouldleak at a rate of 20receive the appropriate credit within the Appendix R requirements could take gallons per minute. Results of analyses credit for that equiprnent,if avausble, performed for GI 23 will preside the USI A-44 resolution by either changirs the emergency ac power configuration for coping with a station blackout event.

informatron necessary to estimate RCP group or providing the abihty to cope 7. The estimated resource burden un the

' stal behavior dunns a station blackout.

ne industry coping analysis guidetnes with a station blackout for an extended NRC associated with the backfit and the (NUMARC-o?00) recogture the period of time. Well bef are plant availability of such resources.

modifications, d any, will be possibihty ofleakagrs exceeding an assumed 25 gpm per pump and implemented to comply with the station The estimated total cost for NRC incorporate the need to reevaluate the blackout rule. it la antacipated that the review ofindustry tubmittals req; ire.1 proposed techocialresolution of USI A- by the station blackout rule is $1.5 ohnt. specific coping analysis if the solution of Gl 23 identies higher 45 will be pubbshed for pubbe comment. mitivon based on subrnittals for 100 s els. Those plants needing hardware reactors and an estimated averige nf rnodifications for station blackout rotald 175 person hours per reactor,

l Feder:1 Rigister / Vol. 53, No.119 / Tuesday, June 21, 1988 / Rules and Regulations 23219 8.The potentialimpact of differences in and eliminate an unnecessary burden on preparation of a Federalism f acility type, design. or age on the the pubtfc. Assessment.

relevancy and practicahty of the backfit.

trrscTive OAft: June 30,1988. The FAA has determined that this The :tation blackout rule applies to all Aoomtssts: Information pertalning to g "

pressurized water reactors and boiling ,g E uu\ O 2Q1 1 this action may be examined at,the water reactors. However. n determining Rules Docket. Office of the Regional impracticable for the agency to follow an acceptable atation blackout coping the procedures of Order 12291 with Counsel. Room 1558. 601 East 12th capability for each plant, differences in Street. Kansas City, Missoun 64106. respect to this rule since the rule must i plant characteristics relating to ac be issued immediately to relieve an l Fon runTuta peronuATso44 cowtAct:

power rvliability (e.g., number of unnecessary burden on the public. If this  !

emergency diesel generators, the Mr.PaulO.Pendleton Aerospace action is subsequently determined to reliability of the offsite and onsite Engineer. Wichita Aircraft Certification involve a significant regulation, a final emergency ac power systems) could Office, ACE-140W FAA.1801 Airport regulatory evalua tion or anal) sis. a s Roa d. Room 100, Mid. Continent Airport. l result in different acceptable coping appropriate, will be prepared and capabilities. For example, plants with an Wichita Kansas 67209; telephone (316) piaced in the regulatory docket already low risk from station blackout 946-4427. (otherwise, an evaluation la not i because of multiple, highly reliable ac sumptaWENTARY MFORMATnow: required). A copy ofit when fild, may I power sources ate required to withstand Nrworthiness Directive AD 80-04-09 be obtained by contacting the Rules

( Amendment 39-3697) (45 FR 8950, Docket under the caption "Apomassts" .

e o of i e and e ,if a February 11,1980), effective February at the location identdied.

ardware backfits would be required as 16,1980, requires installation of an insulated fuel hose in accordance with list of Subjects in 14 CFR part 39 j a result of the rule, plants with currently higher risk from station blackout are Cessna Single Engine Customer Care Air transportation. Aircraft, Aviation '

required to withstand semenhat longer Smice Information Letter SES60 on safety, Safety, duration blackouts: and, depending on certain Cessna Models T210M, T2103 1 Adoption of the Amendment their existing capability, may need sorne an 2 e ann. i modifications to achieve the longer determined that Accordingly, pursuant to the authority {

station blackout capabihty. MstaHadon of the baulated fuel bose in delegated to me by the Administrator, '

eccordance with AD 80-04-09 does not the Federal Aviation Administration

9. Whether the backfit is intenm or final provide an increase in protection amends i 39.13 of Part 39 of the FAR as and, if interim. the justification for foHows:

asainst fuel vapor problems a socialed imposing the backfit on an Interim basis. with these airplanes. AD N15-01, The station blackout rule is the final which required a placard deshng with PART 39-[ AMENDED) resolution of USI A-44,it is not an fuel flow fluctuations. has been 1. ne authority citation for Part 39 interim tocasure, determined to be most effective in continues to read as followr IFR Doc. a6-1x.51 Fded &2>4a. & 45 am) addressing the fuel 5apor problem

,,,,,,,, , which has not been reported with ar.y .,Aubrity  !

regularity over the past several years.

p.3 g49gg,gU.S Cpg tu4!e).14 1 and 1423.

g, ,y4,, i january 12.1983). and 14 CFil 1189.

fore, the FAA is rescinding AD 84-

2. By rescindtag AD 80-06-09 DEPARTWENT OF TRANSPORTATION This action ermits those airplanes Amendmmt 53697 Federal Aviation Administration previously modified in aecordance with 11ua amendment becomes effecove on June  !

AD 80-04-09 to either operate with the 30.19aa.

14 CFR Part 39 insulated fuel bose or return to the luued in Kansas City. Essoon, on June 11 )

3 original configuration. This action also test (Docket No,00-CE-04 AO; Amot. 3&lt611 permit: those airplanea affeeted by AD Paul K. Bohr, 8644-00 but not currently in compliance Dusesor. Centro /Regrott DM 1 and P2to with this AD to remain in the origmal configuration. [F1t Doc. e&13969 Fded &m-set a 45 am]

i A#P **** au mocaosana.tus This rescission will not result in any __

Antwev: Federal Aviatico increase in cost to the pr4ste sector and Administration (FAA). DOT, will remove an unnecenary burden on 14 CFR Part 71 i

ACTsome Final rule, resciaalon. the public. Darefore, it is found that notice and pub!!c procedure hereon are ( Alrapace Docket No. 94-ASO-31 l sueeuARY:his amendment rescinds impractical and contrary to the public Airworthiness Directive (AD) 80-04-09, interest, and good cause exists for Amendment to Control Zone'-

e j

Amendment 39-3697, applicable to Cessna Models T210M,T210N and making this amendment effective in less J**** E than 30 days. Aotwcy: Fedetal Aviation P210N airplanes. Subsequent to the ne regulations set forth in this j Administration (FAA), DOT, lasuance of AD 8044-09 the FAA amendment are promulanted pursuant to completed a detailed review and authority in the Federal Aviation Act of Actioec Final rule.

analysis of the service history of these 1958, as amended (49 U.S.C.1301, et 1 airplanes and has determined that the spesa.aRY: his amendme it changes the 4 seq.) which statute is construed to published hours during whju the actions required by that AD do not preempt State law regulating the same control rena is effective.nis acti.,n provide an increase in protection subject.Thus. In accordance with 0 against fuel vapor problems. Bis action extends the efrective hours to include Executive Order 12612, it la determined periods of increesed instrument flight will delete the necessity ofinstalhng en that such regulation does not have activity at the MCAS New River insulated fuel hose on these airplanes, federalism implications warranting the (McCutcheon) Airprt.

,i, s

s