ML20128F069

Summary of 930122 Meeting W/Licensee in Palo Alto,Ca Re Policy & Technical Issues Associated W/Nrc Staff Review of EPRI Util Requirements Document for Passive Plant Design

ML20128F069
Person / Time
Issue date:	02/01/1993
From:	Hiltz T Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
References
PROJECT-669A NUDOCS 9302110229
Download: ML20128F069 (34)

Text

,

o UNITED STATES y[

g NUCLEAR REGULATORY COMMISSION p,

W ASHING T ON, D. C, 20$ss g

j

\\,,,/

February 1, 1993 Project No. 669 APPLICANT:

Electric Power Research Institute (EPRI)

PROJECT:

Advanced Light Water Reactors (ALWRs)

SUBJEC1:

SUMMARY

OF MEETING BETWEEN SENIOR NUCLEAR REGULATORY COMMISSION MANAGERS AND ALWR STEERING COMMITTEE REPRESENTATIVES (JANUARY 22,1993)

On January 22, 1993, senior managers from the U.S. Nuclear Regulatory Commission (NRC) Office of Nuclear Reactor Regulation met with members of the ALWR Steering Committee in Palo Alto, California, to discuss policy and technical issues associated with the NRC staff's review of the EPRI's Utility Requirements Document for passive plant designs.

The regulatory treatment of nonsafety systems in advanced light water reactor designs was the primary topic of discussion.

Enclosure I lists those personnel who attended the meeting. contains copies of the material presented during the meeting.

An EPRI representative discussed EPRI's understanding of the schedule for issuance of a final safety evaluation report (FSER) for the Passive Requirements Document.

The EPRI representative noted that there does not appear to be closure on several chapters of the draft safety avaluation report (DSER).

Thir was attributed, in part, to issues contained in those chapters associated with tre regulato n treatment of nonsafety systems.

NRC management indicated that li intended to issue the FSER for the Passive Requirements Documents on schdule (as specified in SECY-91-161) and that those issues not resolved in the FSER would likely be addressed in a supplement to the FSER.

However, NRC management noted that they were reassessing the resources required for conducting advanced reactor reviews and, after careful consideration, may modify the completion schedule for all advanced reactor reviews, including the review of the EPRI Passive Requirements Document.

Senior NRC managers and ALWR Steering Committee representatives discussed the urgency to resolve the issues associated with the regulatory treatment of nonsafety systems in passive plant designs. ALWR Steering Committee representatives indicated that they believed that additional regulatory requirements for nonsafety systems are not necessary for passive designs which can meet the EPRI safety goals using only passive safety systems. ALWR Steering Committee representatives indicated that the Passive Requirements Document specifies design requirements, not performance reliability goals.

Senior NRC managers indicated that the staff has an obligation to ensure that defense-in-depth considerations have been appropriately incorporated into the design and that equipment will function when required (i.e., technical specifications).

The NRC will review a design to ensure that reliability, Q

g' maintainability, and availability for, and the ultimate performance of, safety QU, and nonsafety equipment have been properly integrated into the design.

f 050061 fy,'yggy h, hh 9302110229 930201 PDR PROJ 669A PDR

~

~

- 2 '-

February 1,._1993 Performance-of systems and components'must be part of a licensing document, u

The reliabil_ity, availability, and risk-significance should be determined on a system and on a component level. The staff will accept a ' graded' approach to safety with the requirements for nonsafety structures, systems, and compo-nents, proportional to their respective safety significance. - for certain nonsafety systems,Jthe Reliability Assurance Program-(RAP)_and the=implementa-tion of the Maintenance Rule may be acceptable regulatory oversight.

However,-

regulatory oversight relying only on the implementation of the RAP and of. the t

Maintenance Rule 'will not always be appropriate and other ' considerations, such.

as specifying.* conditional' technical specification allowed outage times, will have to be considered.

. contains an approach, which was determined'to be generally acceptable by both senior NRC management and ALWR Steering Committee repre-sentatives, for developing a process to address the regulatory treatment of nonsafety systems in passive plant designs. The staff will review the ultimate performance of a system or component to meet its intended safety'..

function, will consider defense-in-depth design for that function, and will-determine whether the design meets NRC requirements and safety goals.. For example, containment sprays will not be required if the performance of the containment can be demonstrated to be adequate without sprays. Additional interaction between the NRC staff and EPRI representatives will be required to fully develop and implement a process which can be used by designers for specifying reliability and availability missions for risk-significant. systems, structures, and components, which are needed to meet NRC requirements and.

safety goals.

Representatives from Westinghouse and GE Nuclear Energy discussed-defense-in-depth considerations for the AP600 and the Simplified Boiling Water Reactor, respectively.

EPRI representatives discussed source term related issues and presented an overview of the passive plant design-RAP and operational-RAP.

The NRC staff presented information on reconciliation of the differences between the EPRI and Lawrence Livermore-National Laboratory seismic hazard curves. A public workshop to discuss the process used to develop and recon-cile the curves will be scheduled for later this year.

(Original s.igned by)-

Thomas-G. Hiltz, Project Manager Standardization Project l'irectorate Associate Directorate for Advanced Reactors and License Renewal Office of Nuclear Reactor Regulation-

Enclosures:

DISTRIBUTION w/ enclosures:

As stated Central File PDST R/F PShea JHWilson PDR cc w/ enclosures:

JMoore, 15818 ACRS (li)

GGrant,:EDO See next page THiltz DISTRIBUTION w/o enclosures:

DCrutchfield' TMurley/FMiraglia JRichardson WRussell AThadani RBorchardt JThompson.JNWilson-HGraves.

SBajwa-JMoore, 15B18 E3ordan, MNBB3701 0FC:

LA: POST:ADAR PM:

ADAR SC:

T:ADAR

NAME: PShea M THi

tz RB ardt DATE:Oly/K

/93 01/ //93 0FFICIAL RECORD: COPY: MTGSM122.TGH c

i f

i--

fe ;lL

_,i NRC/ALWR Utility Steering Committee Meeting :

Rickey's Hyatt Hotel /Palo Alto, Califomia -

- 22 January 1993 '

Andersen,Ted

_..Westinghouse Baechler,Jeff GENE-Berger, Jean Pierre EPRI/EdF-Berryhill,' Bob EPRI:

Bliss, Henry Commonwealth Edison

' Board, John Nuclear Electric -

Bockhold, George EPRI/ Southern Nuclear Bra'dbury, R. B.

Stone & Webster Bruschi, Howard Westingouse

~_

Buchholz, R. H.

GE NE Burke, Rich EPRI Chapin, Doug MPR Assoc.

Crutchfield, Dennis USNRC/NRR Cunliffe, John.

Bechtel-

~$

.Delvin, Sandra.

GENE DeVine,Jaek Polestar Driscoll, Steven ARC /INPO -

Duncan, Jack GE NE Fernandez, Tom YAECo

_ Fidrych, Leon F.

SLI-

. Franks, Sterling M. -

l DOE' Frieling,Garry.

Wisconsin Electric Gabarain,Telmo -

EPRI/UNESA -

L Glumtz, Doug GE Nuclear-

_ Goldenberg, Enrique Bechtel

+

l

- Green, Ken Sargent & Lundy Hiltz, Thomas G.

USNRC/NRR 1rie, Toshic'

-JAPC Jackson, Charles Con Ed Karr, Ken INPO -

_ Kato,Senji EPRI/JAPC.

Klente, Friedrich

.VDEW I.ayman, Bill EPRI

Leaver, Dave Polestar l}

Mall, Kashmira -

US/ DOE s

Marston, T. U..

- EPRI i:

' Matzle, Regis

_ ABB-CE -

McCandless, Roger --

-GENE Mcdonald, R. P.

Southern Nuclear -

McIntyre, Brian Westinghouse

. Montani, Mitsuto -

EPRI/jAPC Mrtgat, Christian Tenera'

- Murley, Thomas NRC

-Newton, Roger,-

Wisconsin Electric Ng, Ray O

-NUMARC Noviello, Luigi ENEL S. P. A. Italy Piccini, Giovanni EPRI/ENEL ;

- Pusheck,; Bruce Grove /EPRI ~

s

' Enclosure'1-

o.,

a Qultk, Joe -

GE/NE Rao, Atam GE Nuclear Reynolds, John P.

Southern Nuclear Richardson, Jim -

NRC Roberts, Thomas FP&L/ ARC Roch, Maurice Tractebel -

Rumble, Ed Polestar Russell, William T.

NRC Sanford, Mark TVA Santucci, Joseph EPRI/ ARC Schulz, Terry Westinghouse Sliter, George EPRI Sordini, Stefano ENEL/EPRI Sterdis, Andrea Westinghouse Thadanl, Ashok NRC Thompson, John W.

USNRC/NRR Trotter, John EPRI/ALWR Vidard, Michel EdF

\\

Vijuk, Ron Westinghouse Wagner, Kurt EPRl/RWE Energie Wales, Tim EPRl/PP&L Welty, Chuck EPRI i

White, Jim ORNL Wilson, David EPRI/Niag. Mohawk.

~

Wilson, Jerry N, USNRC/NRR Wolfe, Ulrich EPRI/RWE Energie Wyke, Tom Duke Power Yedidla, Joe EPRI ZimmermanniAnton HEW

. 4 i

F i

4

EPRl/NRC Overall SER Status and Schedule J. Trotter.

Advanced LWR Program EPRL'NRC Policy issue Status Most Porcy issues (SECY-90-016 family) have ALWR Program agreement The Major issue yet to be resolved for Passive Plants is

1. 111A Regulatory Treatment of Non Safety Systerns I believe agreement on ALL other Policy issues is at a stage where all parties only need to examine the exact words of the Policy proposals Implementation details on some ageod to issues are not yet spefied out (exanple: #1.A, Use of Physically Based Source Term)

Advanced LWR Program 4

a

s EPRLHRC Expected Dates for URD SER Activities Volume lli Safety Evaluation Report SER Input to Project Manager non Por,ey end Jan SER Drafts, Chapters 2,4,7.12 mi4Feb7 SER Drafts, Chapters 1 A,10,13 mi& March?

SER Input to Project Manager. Policy 4/1rd93 SER Drafts, Chapters 1,1B,3,5,6, 8,9,11 fd18/93 ACRS Review 8/20/93

- Commission Review and Deelsion 9/23/93 Volume 11. Suppfement 1 Ahor ABWR & System 80+ SERs Volume lit, Supplement 1 mid-19947 Advanced LWR Program

,,,c EPRl/NRC Chapter Status Chapters with essentishy all URD changes and SER inputs: 2,4 & 7 Chapters with essentially all VRD changes and SER inputs done or agreed-to: 1 A,12 Chapters with URD changes pending and/or ongoing discussions wkh NRC and ALWR staffs:

10,13 Chapters whh essentla!!y no conclusive dialogue after the DSER:1,1B,3,5,6,8,9,11 Advanced LWR Program l

l:

O-EPRLHRC Chapter Challenge Summary.

• Chapter 1 littie d;alogue to date, corrplex chapter Chapter 10 different views of NRR and RES Chapter 3

-need decision on RTNSS (D.I.D. Systems)

Chapter 5

-need decision on RTNSS, cornplex Chapter Chapter 6. -need decision on RTNSS (Anangements)

Chapter 8

-need deelslon on RTNSS (Coonng Systems)

Chapter 9

-need decision on RTNSS (Other Support)

Chapter 10 -new staff positions Chapter 11

-need decision of RTNSS (Electrical Systems)

Advanced LWR Program e.

EPRVNRC Regulatory Treatment of Nonsafety Systems Passive Plant Concept and Approach GeorDe Bockhold i

Advanced LWR Program

l l

EPRLHRc Passive System Licer' sing Ba9es Address traditional deterministic licensing regulation modified by optimization subjects and enhancements such as severe accident requirements Passive safety systems have robust performance requirements, a couple of examples are the followiry General Design Crheria are addressed including redundancy' and single f alfure crheria Conservative analyses are performed for licensing design bases (LDB) events DNershy for the Passive ALWR is similar to the Evolutionary ALWR licensing considerations Decay heat removal, inventory makeup and ATWs have sirrdlar drversity (dNerse systems are required in the URD)

- Designers must demonstrate that common mode failures do not compromise ALWR goals, CDF < 1,0E 5 per plant year or 25 REM release < 1.0XE 6 per plant year Passive plant requirements do not place a critical dependance on active nonsafety systems Advanced LWR Program

,,,c.,

EPRLHRC Goals for Containment Performance

= Containment is a safety grade system for licensing design basis accidents and transients Best estimate analysis is used for severe accident containment performance

- Meets comprehensive list of containment cha!!enges Containment loads from low pressure core mett sequences do not result in exceeding Service Level C for at least 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Beyond 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, there shall be no uncontrolled release

- Advanced LWR Program i

a-EPRVNRC Commission's Safety Goal Policy Statement

. ALWRs address the Commission's Safety Goal Porcy Statement by confirming that a probabihstic risk assessment (PRA) sensitrvity study, assuming no credh for nonsafety defense-indepth systems after tr.p si na! rnests this Doal (c1.0E-4 per plant year CDF,large re ease <t.oE 6 per plant year)

Best estimate analyses considering uncertainties are used for PRA goals Nonsafety systems reduce the risk of transient chaffenges when transients can be terminated by a controiisd shutdown Best estimate credt is given to containment performance for severe accidents Method for determination of performance / reliability goals Advanced LWR Program EPRl/NRC NRC Technical Issues Regarding Passive Systems NRC staff states that meeting the Commission's Safety Goal

+

Policy will require highly reliable passive safety systems.

NRC staff believes that it will be very diffeu!! to show evidence to support the needed level of reliability. Spec!fic equipment mentioned:

GDC check valves natural circulation robustnesa

- heat exchanger effectiveness

- ADS vatves/ operators

- vacuum breaker leak requirements

- operator systeminteractions Advanced LWR Program m.,,

s.

t EPPLHRC Test and Analysis &

Adverse System interaction Requirements Test (for code verifkation)ical phenomena and saf ety systems /.

andor Anafysis programs must demonstrate that the phys components will function as intendedior design basis accidents and transients Transients and accidents considered in PRA evaluations must use appropriate engineering analyses which provide justiftation that physical phenomena and systems /

corrponents will function as intended Evaluations of both design basis and beyond design basis (PRA) transients and accidents will be made to investigate and ad$ess system interactions inefudine eeerator reseense Requirements that the Designer must demonstrate compliance for Design Certification Advanced LWR Program

.,,c EPRLHRC The Missions for Nonsafety Systems Have econone utility for electric production, improve flexbility in plant operatien ano,mrovide investment protection

• Comptement safety systems by reducing the challenges to safety systems PWR charging & BWR CRD (also with off site power, feedwater) pumps prevent smail leaks from actuating depressurization systems e nd support normal shutdowns PWR NRHR & BWR CRD (afso with off-site power, feedwater) pumps prevent (full) depressurization for small to medium RCS breaks PWR backup feedwater prevents in most transients actuation of passive decay heat removal systems Advanced LWR Program

EPRl/NRC The Missions for Nonsafety Systems (Continued)

+ Reduce the likelihood of safety cht!!anges when a safoty system is in a limited condition for operation. for exartple PWR backup feedwater ar.d BWR CRD pumps can cortpensate for unavailability of passive decay heat remova!

Nonsafety Systems Provide investment -

Protection Beyond Commission Safety Goals Advanced LWR Program EPRl/NRC f

Regulatory Treatment of Nonsafety Systems URD Requirements for Defense-imDepth Systems PRA Study to Assess Passive Safety Systems E. Rumble Advanced LWR Program

,,m,,

i L

EPRtHRC

.]

Defense-in-Depth Systems I

Defined in Chepter 3, Section 2.3.1 Reactor coolant rukeup function

- ChemicalVolume & Control Systom (PWR)

- Control Rod Drive Systom (BWR)

Reactor decay heat removal functk>n

- Reactor Shutdown Cooling System (PWR)

- Reactor Water Cleanup System (BWR)

, Steam Generator Backup Foodwater System (PWR)

Spent fuel decay heat removal function

- Fuel Pool Coobg and Cleanup System (BWR &PWR)

Systems and structures needed to support the defense-in-depth missions of the above systems Advanced LWR Program EPRLHRC I

PacSive Plant ALWR Requirements for Defense-in-Depth Systems

• arrangernent and radiation shielding to permit access for operation and maintenance to permit recovery from non accident events leading to operation s,he PSIS & PDHR systems Systems and required equipment identified for use as part of the Severe Accident Management Program sha!! meet equipment survivabitrty requirements specified in Chapter 5, Section 2.4.3.4 Redundancy provided assuming a single active failure of equipment which must change state or position to perform its defense-in-depth function -

Ensure that specified design limits for plant infrequent and Moderate Fr;;uency events defined in Chapter 1, Section 2 are not exceeded without reliance on saiety systems except the RPS Chapter 3, Section 2.3 unless noted otherwise Advanced LWR Program

,,.c.

~

Passive Plant ALWR Requirements for Defense-in-Depth Systems' (continued)

Ermloyed to the extent necessary to ensure that depressurization le a -

very low probability event Serve as the first line of defense for pipe breaks for s's inch or lose inside diameter pipes Electric power evallability from both normal station oc power and the on she nonsafety ac power supplies Electric power to redundant equipment (or trains) should be separsted to the extent practical (i.e., power from separate buses) j Redundant cormonent protection against intomal flooding and in+! ant.

+

hazards (Also Chapter 9, Section 3 for fire protection)

Analysis (and testing) to demonstrate system capab!!ity to satisfy its defense in-depth toquirements Chapter 3, Section 2.3 unless noted otherwise Advanced 1.WR Program EPRl/NRC Passive Plant ALWR Requirements for Defense-in-Depth Systems-(continued)

Nonsafety structures and equipment designed for so!smic requlromonts in accordance with the UBC of Zone 2A (Chapter 1, Section 4.3.2.3) ;

I Nonsafety structures designed for extreme winds in'accordance with l

Chapter 1, Table 1.2 6 and Section 4.5.2.1.2 Requirements specified in the URD are the trinimum to be provided.

=

Plant Designer may add further requirements and features as determined by analyses and as necessary to meet ALWR Passive Plant safety and investment protection goals (Chapter 3, Section 2.3.3) -

. Design requirements throughout Chapters 1,2,3,4,6,7,8,9,10 and 11 '

j:

on the defense-in-dopth systems and their support systems Advanced LWR Program 4

.i

.L..

s.

n EPRl/NRC PRA Study to Assess Passive Safety Systems PRA nooreach to guns das!gns whhout credM for DiD systema Start w!th the Designers' baseline Level 3 PRA that considers intemal and extemat events at power and during zero power operations Ensure that the assumptions, numar' al estimates o nd models are c

cortplete to the extent possble and defensble Remove the effect of the DiD systems defined in Volume til, Chapter 3 section 2.3.1 of the URD fromthe event tree models by setting their unavailability to 1 Advanced LWR Program o,

EPR1/NRC PRA Approach to Assess Designs Without Credit for DlD Systems initiating event frequencies are not altered

=

- DD systems are available for their operationalm%slorn

- NRC review of DiD systems for abildy to reduce challenges to thei safety systems

• Analyze the Level 3 PRA rnudets for internal and extemal ei ents and power and zero power operations based on the revised eve nt trees which do not credd DiD systems

- Study the defense in-depth capability c! the safety systems Assess the level of safety achieved without credit for the DiD systems Examine the need f or DiD systems' missions to back up the safe *y systems after a trip

- Advanced LWR Program E

.r EPRVNRC PROPOSED ACTION PLAN (Commission briefing on W3/92)

Continue ALWR / NRC Interaction based on f allowing princ41os:

Define acceptable performance requirements that passive safety systems alone are adequate to protect public health and saf ety Dr.itne acceptable Refiability Assurance Program (RAP) rsquirements which provide appropriate regulatory treatment of both safety and nonsafety systems Document these requirements in URD and NRC acceptance in FSER Assign proof of passive system performance to design teams witt, NRC acceptance via Cemfication process

- Advanced LWR Program c.,,

EPRl/NHC Source Term Status and Resolution l

l D. E. Leaver i

Advanced LWR Program i.

)

^

source Tenn sistue end me.ouke summary Sowee Tenn URD Rtl Dren Annett tJ tC Based

Blaism, EA.testfjacter.at NRA Ramehaana voastae Romane Funamn s a

Ckne atraeaud UFO VoleFSER Chemme Fene s

a Ckse egreemwe URDVoieFSEM towg a

e Tewg stie<,=cus som ese to URD ved m pstR (weh esowenes tar pene spese esposes 6beemos 6er pes 4 speefe sepsmes)

Lee voetee Asseene a

a M S 14100 ts*me lugNer URD Voi m FSCR sw Breteen W SER Fre.4mm swn ALwm Cornarscree DeaNrW 3

RES dreR #epest due URD Vol111 GER Scypieaud (eeh r

-poe1983 shwem to peam speefic espace4 Aeronal Marwee.end orda Ar600 ed $5WR SER Swwwaseen Poe Sombtsne RESeratneemttwo URD Vait Fstm Supywnere sneer s

Sproye a

Fetruary,19e3 Spism & $ER seamoary evner, a

honom URD ve m ScR seaw ore toen wo,eer.eesUMD y sea

.=me s.o.e.

eu.eaue ser pi.m es. eve espase.)

Haeme panna d ene weer sevoopast ease 88WR SER URD Ved W F5ER Ckma egeoeau4 en UHD..

poi Ceraal s

a

+

w, eve.,<,..e freene W890498ter

.%.e e.tetWR Charonal s

honeN ALvme we.ah nie.et Part 100 URD Vo.f m F.EER anese e.e me,s 8.n e -

Ses R

e,n e--eee Debns Pocd Soutunn Under reves by AtwR URD Ved m FSEM en&W Sp b MR m ie e. e e.ee, e.a. e.,a e - e e, EPRLHRC Schedule for NRC Documents Which Impact Source Term SERn Passive Plant URD Vollil FSER 9/93 e

Systern 8% SER 11/93 e

URD Volll and Vol til SER Supplements

- mid-1994 AP-600 SER 6S4 e

S8WR SEP BS4 e

Regulatorv Gulde ee NUREG 1465 (2nd draft or final)

- 5/93 a

(revised soprce term)-

New Reg. Guides Not yet scheduled e

fluita Draft Part 50 Rule issued for comment

- 10/93 e

,,,.,e,'

Advanced LWR Program

w,-

1 n _-

l 1

EPRLHRC Approach to Resolution Acattel Aeproach j

• Achieve technical resolution in an SErl as earfy as practical Allow 1or incorporating plant specNic aspects wtiere appropriate,

Codify resolution in Design CertNication ALWR and NRC continue regular rnestings to resc!ve differences Apsmash ior Pottn11 ally Diffleutt lasuas Low Vo(atile Release Fraction Request NRC apply latest experinnntaf information to revise estimate downward (per ALWR October,1992 letter)

• Containment Natural Aerosol Removal ALWR will review RES draft report when svallable and provide -

fesiback Westinghouse and GE to provide plant specNic Information Request NRC to recognhe this phenomena for licensing and to incoporate allowance for plant specific aspects Advanced LWR Program

,,c EPRLHRC Approach to Resolution (continued) l!ntciolyrdhtue Approach Secondary Building Holdup ALWR complete more specific URD requirements and eranple applications (mid 1993 Westinghouse and GE)to provide plant specNic information Request NRC to recognhe this feature for passive BWR licensing and for passive PWR PAGs, and to incorporate allowances for plant specific aspects Containment Sprriy ALWR review RES draft report when available and provide feedback ABB 1o provide plant specific intormation ALWR review NRR dose assessment (when complete) to further assess N spray is required to meet Part 100 limits -

Charcoal Each Plant Designer to provide plant speelfic Information ALWR review NRC dose assessment (when complete) to further assess il charcoal is required 1o meet Part 100 lirWts Advanced LWR Program

_.... o EPRLHRC ALWR Emergency Planning D, E. Laever I

Advanced LWR Program EPRl/NRC Status of ALWR EP Effort EP Action Plan submitted to NRC in June,1992 EP criteria and methodology is undergoing fitta! review prior to transmittal to NRC as URD revision (expect transmittal in

-1 February,1993) i.

Advanced LWR Program I

I I

1

,m.

r FPRVNRc Emergency Planning Action Plan

• An Emergency Planning Action Plan was submitted by the ALWR Program to the U.S. NRe in June.1992

• The key points of the Action Plan were as follows:

Imptoving the emergency planning process, particularly wkh respect to offsite planning, is a crucial step in achieving the goals of the NPOC Strategic Plan.

The primary basis for changes to emergexy planning are the severe accident prevention and mitigation aspects of the ALWR design Generic resolution of emergency planning issues is necessary for standarddation; this resolution should be as earty as practical, preferably in parallel with Design Certifecation Advanced LWR Program

,,,c,

EPRVNRC Parallel Approach for Accomplishing Regulatory Change for ALWR Emergency Planning ikAniske of Ccubfy ALWR AL E ancy "**

Emwgency mnning

=

cw i

'Li;

~

+

j Emagency l

Referetre to Plae ntan' DC and j

Meibodology j

Gerwric Rule j ror Containment I

Fwf m.

t Codify that PAC Du.e Crtwrta for gg,g and PRA ALWR Emetgency ;

Flant bgn l

Nnrung Meets Croens i

URD and SER

,Generlo DC i

ISP/ COL i

' Rule '

s 3/92 9/93 7/95 TBD Advanced LWR Program

,,.c.,,,,

EPRLHRc Summary of umergency Plannir.g Criteria Crherion 1 Containment Performance e

Meet existing Chapter 5 requirements addressing corrprehensive list of containment challenpee Containment loads from low pressure core meh sequences do not result in exceeding Service Level C for at least 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Beyond 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, there shall be no uncontrolled release Crherion 2 Site Boundary Does Dose from physically based source term for everage meteorology doss not exceed 1 rem for a period consisting of time for accident detection, notification, and ad hoc evacuation A period of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is considered sufficient Advanced LWR Program EPRLHRC Supplemental PRA Evaluation in Support of Emergency Planning Criteria 4

Meet 10 per year core damage frequency.

e Meet 10* per year,1 rem at site boundary Meet the quanthat!ve health objectives of the NRC Safety Gcal Policy with no credit for evacuation prior to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />

,,,,A Advanced LWR Program

I

+

EPRLHRC Seismic Effects & Design Considerations B.Pushock Advanced LWR Program

,,,c EPRl/NRC URD Seismic Des!gn Changes Ut2ity Pequirements Document changes for seismic design requirements prepared NRC staff review wiD be requested whh submittalin February a

Recognize 1neeJ for standardized seismie desl o *PProach D

NRC SER disposhion encourages un!fied lodustry approach -

Objectives:

- clarify standard zed plant soisinic design basis

- avoid excessive design conservatism define range of generic foundation soli categories reconcile standard design whh she condhions Advanced LWR Program m.,

a EPRLHRC Low Level Seismic Effects OBE previously eliminated as design requirement URD revision changes fatigue evaluation crheria '

comgnent'systom anaYsis:

20 SSE full stress cycles or equN. fractional vbratory cycles

. component testing: E anplitude events plus SSE evert frve one half SS URD revision modifies plant shutdown criteria

=

. current criteria:

cumulative absolute velocky (CAV) exceedance revised URD requirement plant shutdown if 005 and CAV exceeded (OBE = one third sitecpecife SSE free-field spectrum)

• proposedfatigue criteria consistent w/NRCposition in R.C.

Pierson letter to GE, Sept. 11,1992 Advanced LWR Program EPRLHRC SelSmic Design Site Unique Facilities (facilities not defined as part of certified design)

Safety related site unique facilhies

~

clarify desigrV analysis uses she specif'c SSE ground motion spectrum peak grounw acceleration site specifo soilprofiles/ parameters Non-safety site unique faci! Ales a

Uniform Building Code (UBC) design basis Owner specres UBC seismic zonation Advanced LWR Program o m,,

I EPRLHRC Seismic Category 11 Structures (non safety rotated structures,if felledcould Interect with safety related)

Current URD methodology analyro category 11 structures to SSE

. permh ductility in collapse analysis Proposed ORD seismic change permits alther:

seismic design of category Il structures to UBC rone 3*

SI ana'yre structures to SSE: ductility perrrdtted Addition of URD tornado criteria for category Il structures

. analyze to prevent structural collapse

• consistent wkh NRCposRion on ABWR turbine building Advanced LWR Program o,,

EPRLHRC Safe Shutdown Earthquake (SSE)

Proposed URD change would define the SSE application more explicitly for design of standardized plants SSE ground motion (Reg Guide 1.60 anchored to 0.3g peak ground acceleration) shall be conaldered ony at the surface of the free field

- specNy that Reg Guide 1.60 not Intended to be applied at hypothetical rc,ck out crop f or sha!!ow soil sites Provide generic soil categories for sand like and till-like soils e

- define a range for shear wave velocity with depth to bedrock Plant Designers soil profile cases to be encompassed by URD range Advanced LWR Program

e.

r ny EPRVNRC o

Soll Structure interaction Analyses -

4 Reference SSI rnethodology and modelling assumptions Designer to consider spatialvariation of ground motion e

to reduce responss spectra at basemat artplitude variation

. incoherence 1

Advanced LWR Program 5

EPRLHRC DynamlC Analysis of Piping -

' Use of calculated floor response spectra (FRS)

- from individual soll-structure interaction analysis sete -

enveloped FRS only if it doesni increase restraint nurrbers Modelling guidelines, examplosi e

-include support stiffness where deflection > 1/16 inch -

. criteria for deeoupling branch p* ing p

- nozzle stress set approx. 50% Code allowable

= -- Specify Seismic Anchor Movement stress criteria in reference letter NRC to GE dated Sept.11,1992 Advanced LWR Program yy

~ ~

,t-.-

w

4 O

EPRWRC Reconcillation of Design to Site. Specific Conditions important to define the approaches neceptable to reconcle e

standard plant de ign to site speeric condnions Several approaches defined, depending on level of seismic risk at selected she

. determine she 6 pectic SSE, yound motion spectrum and PGA

. tredPy G M. spectrum in high f requency ranoe where appropriate (reference rnethodology in draft EPRI report)

.comparo rrodified she specNic SSE spectrumto design SSE

. for soll shes whh profile signWicardY dNierent from doelen cases, perform SSI aneYoo

. compare FRS from she SSE with design FR8

. portorrn system evaluation for significant exceedences of des:gn FRS

. perform cormonent level evaluation Advanced LWR Program EPRWRC Conclusions The specNic guidance /requironwnts provided in proposed URD changes will:

. enhance industry standardgation objectivoo

. sirmlify NRC review offort of individual applicatio6s Recommendation. NRC management should provide a o

+

window of opportunhy for staff review and meetings wth Edustry (EPRI & Plant Designers) consistent with February URD submhtal and final SER preparation Advanced LWR Program d

.,,,.,b

- s_.. - -.

t EPRLWRC Passive Plant D RAP & 0 RAP sobs.tryhui Advanced LWR Program EPRLHRC D RAP Provides cortrols for design reliability activities -

Provides information for developrnent of the 0-RAP Reliabillay information

' Monitoring iecommendations Controls reliabilty acthhles until tumover of system to Plant Operatior s.

Advanced LWR Program

o EPRVNRC 0 RAP Scope Safety Systems Normal operation systems that could terminate a transient or bent

+

before plant parameters reach or exceed passke safety system actuation setpoints.

Systems required for completion of Emerooney Operation Procedures safety functions.

Systems that are irtportant contrt.utors to tiek.

i Advanced LWR Program

c =

EPHLHRC 0 RAP Functions Monhoring Performance monitoring CondMon monitoring

+ FunctionalVerification Detense-indepth (DID) functions EOP functions Sys'.em Avalfability Controls Systern Configuration Control -

Specifies mlntmum cortplement of DID systems and passive safety

- ystems to be maintained available.

s

-Places limitations on plant oporating conditions if minimum complement of DID and passke satety systems are not available Advanced LWR Program

,,. ~...

s.

AP600 j

DEFENSE-IN-DEPTH SYSTEM DESIGN 1

Presentation to NRC / EPRI on Defense-In-Depth Systems Design Requirements Sample System (CVCS)

Passive Systems Design Requirements Sample System (PRHR HX)

Summary T.L. Schulz January 22,1993 1

Westinghouse Electric Corporation 1

e

AP600 DID SYSTEMS Defense-in-Depth System Design Process o

Systematic design process URD requirements Selection criteria / procedure Design control QA/QC Document verification Change control Design analysis; best estimate anhlysis, auditable, not in SSAR Defense-in-Depth System Design Approach o

Simplified active systems 4

Support reliable normal operation Reduce unnecessary challenges to passive safety systems Not required to mitigate design basis accidents Limited dependency to meet safety goals TL5 - 1/21/93

e iWO DID SYSTEMS

[

m Defense-in-Depth System Design Features Redundancy for more probable failures Protection from more probable hazards Seismic (UBC Occupancy Cat I, zone 2A, IF 1.25, buildings and-equipment supports)

Extreme wind (110 mph, IF 1.11)

Fire (detection, suppression)

Flooding (limited leak, sump pumps)

Power from redundant non-safety diesels Automatic actuation and controls Defense-in-Depth Equipment Design Features Reliable / experienced based equipment Reg Guide 1.26, Quality Group D Plant procedures (test frequency, repair time, plant modes, planned maintenance, no shutdown requirements)

Reliability Assurance. Program Less detailed Tier I description and ITAAC 1

TLS - 1/21/93

-i l

AP600 DID SYSTEMS i

Selection of Defense-in-Depth Systems Defined in URD Chapter 3 Section 1.5.2 E

Includes systems that prevent unnecessary actuation of the passive safety systems Where actuation ~of the DID system provides PRA benefit Where actuation of a passive safety system may cause an extended pisnt outage Also systems that must function;to support the front-line DID systems-Only includes the portions of the front-line and support systems that provide these defense-in-depth functions

)

1 I

TLS + 1/21/93.

.. ~..

1 AP600 DID SYSTEMS Defense-in-Depth System importance Core Damage Release Frequency Frequency 4

Base Case, all systems

- All events (1) 4.3E-7/yr 2.2E-8/yr

- Internal at power (2) 3.3E-7/yr 2.1 E-8/yr Sensitivity Case, w/o CVS,SFW,RNS

- All events (1) not calc not calc

- Internal at power (2) 2.6E-6/yr 2.2E-7/yr NRC Goal

- All events (1) 1.0E-4/yr 1.0E-6/yr Notes:

(1) All internal and external events from power and shutdown conditions,-

except seismic.

(2) Only internal events from power operation.

.T&S - 1/21/93--

AP600 DID SYSTEMS f

Defense-in-Depth Front-Line Systems Chemical and Volume Control System Startup Feedwater System i

Normal Residual Heat Removal System Spent Fuel' Pit Cooling System Defense-in-Depth Support Systems Component Cooling Water System Service Water System Plant Control System Onsite Standby Power System (Diesels)

Non-Class 1E do and UPS System Diverse Actuation System Fuel Handling System Fire Protection System Primary Sampling System Main Steam System Data Display and Processing System-Radiation Monitoring System

' Main ao Power System Plant Lighting System Nuclear Island Nonradioactive Ventilation Sys l

Central Chilled Water System-L Annex / Auxiliary Building Nonradioactive L

Ventilation System Diesel. Generator Building Ventilation System Standby Diesel Fuel Oil System TLS - 3/21/93

l 4

A3600 DID SYSTENS CVS Functions Safety Functions RCS pressure boundary isolation Containment penetration isolation Boron dilution accident termination Excessive makeup isolation DID functions RCS makeup for leaks RCS pressure reduction s

CVS Features Redundant pumps Power from redundant diesels Automatic start controls Adverse interactions prevented by redundant, safety related isolation features with automatic isolation logic Excessive CVS makeup modeled in SSAR (RCS inventory increase, SG tube rupture)

TL$ - 1/21/93

AP600 SA ETY SYSTEM DESIGN Passive Safety System Design Process o

Systematic design process NRC regulations URD requirements Design control QA/QC Document verification Change control Safety analysis; advanced best estimate codes, control / protection interactions, SSAR Extensive testing; separate effects and integrated tests Passive Safety System Design Approach o

Simplified passive systems Mitigate design basis accidents without use of DID systems Provide core / containment cooling indefinitely, without DID systems or offsite assistance Limited dependency on DID systems to meet safety goals TLS - 1/21/93

A3600 SAFETY SYSTEM DESIGN Safety Systems Design Features Redundancy for single failure criteria PRA based redundancy / diversity Hazard Protection Seismic I equipment / buildings Tornado wind / missiles (300 mph)

Separation for fire and flooding Greatly reduced dependency on operator Safety Equipment Design Features Reliable / experience based equipment.

Improved inservice testing / inspection Reg Guide 1.26 Quality Group A, B, or C Seismic I design

, Qualified Equipment Technical Specifications (test frequency, repair times, plant modes, shutdown requirements)

Reliability Assurance Program Tier i description and ITAAC TLS - 1/21/93-

.----__----_L-____--

_-_____.__-__-______________--_______-a

t 4

i AP600 SAFETY SYSTEM DESIGN Passive RHR HX Functions Safety related decay heat removal 1

Non-LOCA transients Not required for LOCA or-severe accidents f

Passive RHR HX Features Natural circulation loop j

1/2 fall safe isolation valves of-conventional AOV design AOVs are testable at power Actuation by protection I&C (safety related) and-Diverse l&C (DID system) 1 Maintenance spare-HX HX size based on AP600 specific test i

e

.TL5.

1/21/93 ~

1 AP600 SAFETY SYSTEM DESIGN 1

i Passive RHR HX Reliability Detailed system design information System capability; testing and analysis 1

Construction; QA and ITAAC Operability; startup testing, ISI/IST, Tech Spec, RAP Support systems; actuation I&C-Co'mprehensive failure evaluation Screening of failure mechanisms Reliability Quantification o

Success criteria.(1/2 AOV,1/2 HX)

Air operated valve within historical. family;tuse-reliability data from URD KAG Calculated unavailability 7.7 Ei-5-fail / demand 80% due to CCF of AOV 13% due to flow venturi 1 plugging-3% due to IRWST rupture l

>TLs - 2/21/93

... ~.

4-.

1

AP600 SAFETY SYSTEM DESIGN 1

a i

Gas Binding in RHR HX j

Venting required after maintenance Redundant water level alarms in-MCR 1

No source of gas during accident >100 psig r12 in RCS saturated at 30 psig Accumulator empties <100 psig Screened out as failure mechanism in PRA RHR HX Heat Transfer Uncertainty o

AP600 test completed (full pressure & temp)

Plant startup tests required (full pressure &-

temp)

PRHR HX. test required every;refuelingioutage (intermediate pressure.& temp)

Screened out as failure mechanism iniPRA-Condensate Return To IRWST a-Initial water. inventory-. adequate for >72 hr without any condensate. return Screened'out:as. failure mechanism in PRA-itLs - 1/21/93_

~

.)

AP600

SUMMARY

Passive System Design o

AP600 provides high confidence that the passive safety systems will be very reliable Design / analysis / tests Construction inspections / tests Operation inspections / tests DID System Design o

AP600 provides confidence that the DID systems will be adequately reliable Design / analysis Construction inspections / tests Operation inspections / tests AP600 Places Appropriate Requirements On o

Defense-In-Depth Systems TLS - 1/21/93

l 1

4(,

GE Nuclear Energy i

4 i

l-4 c

Requirements for SBWR System Design e

j i-E l

4 5

1 Presentation to NRC/ALWR Utility Steering Committee Doug Giuntz

{

January 22,1993

}'

i l

- ~.

a Presentation Topics r

n

ALWR URD Requirements for Defense-in-Depth Systems as applied to the design of the Control Rod Drive System (CRDS) i 2)

Reliability Requirements for safety-related systems as applied to the Gravity-Driven Cooling System (GDCS) i SBWR's ability to meet the Commission's Safety Goal Policy 3) i I

L i

zet tt t/ZLTJ I.

(

r.

Control Rod Drive System (CRDS) Functions L

i L

Safety-related function - To provide rapid control rod insertion to

=

safely shutdown the core 'and prevent fuel damage l

t i

'l important non-safety-related functions:

L

=

Provide high pressure reactor inventory makeup during l

transients when water level drops to Level 2 Provide;a diverse (from RPS) means of inserting control rods l

upon receipt of an ATWS signal i

L.

?

l-<

q f

i' 3 d ts i

tem l

l l

L

4 I.

n r

n Applicatiorr of Defense-in-Depth Requirements to CROS e

i

{

ALWR URD Requirement Application System arrangementandradiation System arrangemeN! meets all identified a

shielding topcrmitaccess for requirements for secess during operation i

l

. operation and maintenance to permit and maintenance, including recovery t om

)

i recoveryfrom non-accident events non-accidenteventL i

leading to operation ofthe GDCS&ICS l

1 systems 9

Systemsidentifiedforuse aspart of System not required forsevere accidents y

a the Severe AccidentManagement Program shallmeet equipment l

survivability requirements speciHed in l

Chapter 5, Section 2.4.3.4

\\

1 i

-L

'h

.4 5

4 M II I/Ztn3 mz

=

I:

t Application of Defense-in-Depth Requirements to CRDS tcontramem v

J L.

ALWR URO Requirement Application Redundancyprovidedto accountfora Configuredastwo redundanttrains a

smgle active failure (each has50% capacity)

System used to the extent necessary to Automatic onfoffmodeproceeds as a

ensure that depresswization is a very low RPVwaterlevelcycles between probabilityevent level 2andlevel8 a

System serves as the Hrst line ofdefense Automaticallyre-aligns to high forpipe breaks for.NBinch orless (10) pressureinjection mode when RPV

, waterleveldrops tolevel2

[

Electric power availability from both System automaticallyloadedonto m

l normal station ac power and the on-site dieselgenerators in the event ofloss of non-safety-related ac power supplies off-site power

?

[

[

5 of 11 7

1/22,S1

[

i

,_,.-...-,.-.-.-~-....,...-.~,.-...,--,~,-,.-..._...,_..,....~..,,_,-...L

.. ~..

L t

3 t

Application of Defense-in-Depth Requirements to CRDS (coatiaaesj

]

(

ALWR URf] Requirement Application Electricpowerto redundant Separate buses provided for each train i

(

a l

equipmentshouldbe separatedto the extentpractical(i.e.powerfrom separate buses) i 1

e l

Redundant componentprotection a

Excess flowcheck valves at i

n

against internal flooding and in-plant containmentpenetration l

i

^*'"'##

Sumppump capacityishigherthan l.

n leakage flowthrough closedexcess i

flow check valves

\\

m Analysis and testing to demonstrate Added system on-line testability. Freep l

system capabilityto satisfyits testing used to demonstrate that as-built

^

. defense-in-depth requirements capability matches or exceeds defense-in-depth requirements l

e

~,,

1

[

,ams t

.q b

I Application of Defense-in-Depth Requirements to CRDS (coatiauest i

s ALWR URD Requirement Application Ensure that specified design limits for Notapplicable;CRDShas no defined a

plantinfrequent andModerate defense-in-deptir mission forinfrequent i

t Frequency events definedin Chapter 1, andModerate Frequencyevents Section2are notexceeded(assuming no reliance on sefety-relatedsystems

}

exceptthe RPS) i Non-safety-relatedstructures and Fullyimplemented, including water a

i equipmentshouldbe designedto meet supplies seismic requirements asprovidedby the UBCofZone2A

+

p L

r l

3 f or 11

^

1/27)S.T i.

.. :..~

i:

~

i r

Application of Defense-in-Depth Requirements to CRDS (contiaaes) p ALWR URD Requirement Application l

e

' Non-safety-relatedstructures

~

Fullyimplemented, including water L

designed forextreme windsin supplies accordance with Chapter 1, Table 1.2-6

}

and Section 4.5.2.1.2 i

t

~

Requirements specifiedin the URD are Widened conventionalpump m

a the minimmn to be provided. The Plant operating band l

Designermayaddfurther a

Systemisinvulnerable to suction j

requirements andfesiures as e

^ determined byanalyses andas-filterplugging necessaryto meet ALWR Passive m

One trainis always running with Plant safety and investment protection goals (Chapter 3, Section 2.3.3) auto-start ofstandbytrain l

Redundantpump room coolers m

t un r/ZZ5J

A a

Gravity-Driven Cooling System (GDCS) Reliability a

. LOCA plus two active failures willstill allow the plant to meet the Commission's i

Safety GoalPolicy i.

~

Diverse actuation logics for commanding actuation of each squib valve:

m 2-out-of-4 microprocessor based, and 2-out-of-4 discrete component based

+

v Three electrical divisions, each provide a success path through two in-line load a

I drivers forfiring anysquib valve i.

Continuous continuity testing for allsquib valve firing circuits a

n

. Watertight design ofsquib assembly qualified for 100-day LOCA environment a

3 el11 1)2L93

~,,,...

v w,-

~

,. _ J c o-v~

.-.e...,','.

-,-.,, _ ~...,. - -,

, -. + - - - _ _ _

---

m

.w-

-l Gravity-Driven Cooling System (GDCS) Reliability (continued) n ^

Even if all biased-open check valves are frozen in place, the GDCS system still provides adequate coolant into the vessel to prevent core damage Ithe plant will still meet the Commission's Safety Goal Policy) 4 Three different, separatedpools, with two coolant injection lines from each pool a

l Indefinite long-term cooling water supply (via suppression pool water) n-L il Check valves are surveillance-tested at every refueling outage l

n Deluge valve automatic opening provides a guau ntee that waterin the GDCSpools

.a

- will cool the RPVlower head and corium released into the lower drywell.

i i:

o l'

se er n I

1)2732 u

1

31

' Ability to Meet the Commission's Safety Goal Policy Statement SBWR will meet the Commission's Safety Goal Policy Statement by confirming that a probabilistic risk assessment (PRA) sensitivity study, assuming no credit for non-safety-related defense-in-depth systems after trip signal, meets the following goals:

4 CDFprobability < 1.0 x 10 per plant-year (shown by completed work)

(

i Large ' release probability < 1.0 x 10 ~6 per plant-year l

i

(work currently in progress) i 11 et 11 1/72/11 r

'F" M

e w

a e-'r/

4 m

9g Mw*

e er-r*

w 1

es.T*,i

+r>N'We'wgs W m T 9"

9' F

t'9trNT*

r-'-

g 4

%W*

tM1F*+

Develop an overall process consistent with the 22 January 1993 presentation (including viewgraphs, agreements and modifications to viewgraphs) for determining the regulatory treatment of nonsafety systems, and importance of passive systems and/or components for meeting NRC Safety Goals and Requirements. Spedfically:

1.

The Passive URD will describe the p.mcru to be used by the designer for specifying risk significant* SSC reliability / availability missions needed to meet NRC Safety Goals and Requirements.

2.

The designer will apply the process to his des!gn to establish R/A missions for his risk significant SSC's.

3.

If nonsafety systems are determined to be nsk significant NRC will review these R/A missions and satisfy thenucives they are adequate (if met) and that the ORAP and simple tech specs (conditional) and LCO for Eeme items (including the maintenance rule) are adequate to give reasonable assurance the missions can be met during operation.

4.

If nonsafety systems are relied on to meet the R/A missions, then design -

requirements commensurate with risk significance' will be imposed on those elements involved.

5.

NRC will net include any R/A missions in the Design Certification Rule. Instead, NRC would include deterministic requirements on both safety and nonsafety design features in the Design Certification Rule.

ALWR Draft to NRC by 15 February 1993 NRC Comm nts received by 15 March 1993

' crisp definition required Enclosure.3 b