ML20011D318

Forwards Detailed Approach for Review of Preliminary Conceptual Designs of Advanced LWRs That Employ Passive Safety Sys

ML20011D318
Person / Time
Issue date:	12/14/1989
From:	Partlow J Office of Nuclear Reactor Regulation
To:	Miraglia F Office of Nuclear Reactor Regulation
References
PROJECT-669A, PROJECT-676A NUDOCS 8912260161
Download: ML20011D318 (13)

Text

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4 E~# Project Nos.'669 December 14, 1989 676' 7

7 : MEMORANDUM FOR:

Frank J. Miraglia, Jr.

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Associate Director for Inspection and Technical Assessment Office.of Nuclear Reactor Regulation FROM:

James G. Partlow w

Associate Director for Projects Office of Nuclear Reactor Regulation

SUBJECT:

APPROACH FOR PRELIMINARY REVIEW 0F ADVANCED LWRS WITH PASSIVE SAFETY SYSTEMS j

^

-In response to your meeting with W. Travers and C. Miller, PDSLE has developed an approach to be used to review the preliminary, conceptual designs of advanced LWRs:that employ passive safety systems. This approach includes (1)_ familiarization with the current design approaches through meetings with EPRI and the designers, 1

(2) internal review and evaluation of this preliminary information,

-(3) preparation for a meeting away from the office to discuss the staff's conclusions with senior NRR management,.and-

-(4) development of a report summarizing the preliminary policy and technical issues resulting from the staff's: review. A SECY paper will be developed

.to transmit the results of the staff's review and conclusions to the

' i Commission.

In addition,.the-staff will discuss the results of its review with the ACRS. The report will be forwarded to EPRI and the

, vendors for consideration in the development of the passive EPRI Requirements Document and in the vendors' final design of these passive plants.

Enclosed is a detailed review approach including a review schedule with major milestones that need to be met by the staff in order to assure a timely and useful review. Questions and comments regarding the details of the plan should i

be directed' to C. Miller at X21118 or T.J. Kenyon at X21120.

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!amesG.Partlow Associate Director for Projects Office of Nuclear Reactor Regulation n

ec:

see next page PM,hE-D:PDS E ADR4 CF (A)

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iProject Nos. 669 December 14, 1989 1

676~

NEMORANDUM FOR:

Frank J. Miraglia, Jr.

Associate Director for Inspection and Technical Assessment Office of Nuclear Reactor Regulation FROM:

' James G. Partlow Associate Director for Projects Office of Nuclear Reactor Regulation

SUBJECT:

APPROACH FOR PRELIMINARY REVIEW OF ADVANCED LWRS WITH PASSIVE SAFETY. SYSTEMS In responte to your meeting with W. Travers and C. Miller, PDSLE has developed an approach to be used to review the preliminary, conceptual designs of advanced LWRs that employ passive safety-systems. This approach includes (1) familiarization with the current design approaches through meetings with

. EPRI.and the designers,

. 2) internal review and evaluation of this preliminary information,

(

(3) preparation for a meeting away from the office to' discuss the staff's conclusions with senior NRR management, and.

(4) development of a report sumarizing the preliminary policy and technical issues resulting from the staff's review. A SECY paper will be developed to transmit the results of the staff's review and conclusions to the Comission.

In addition, the staff will discuss the results of its review with the ACRS. The report will be forwarded to EPRI and the vendors for consideration in the development of the passive EPRI Requirements Document and in the vendors' final design of these passive plants.

Enclosed is a detailed review approach including a review schedule with major milestones that need to be met by the staff in order to assure a timely and

useful review. -Questions and comments regarding the details of the plan should l

be directed to C. Miller at X21118 or T.J. Kenyon at X21120..

a es G. Partlow L

Associate Director for Projects l

Office of Nuclear Reactor Regulation ec: see next page h

PMhE D:PDS ADR4 CF (A) LD ADF TKbn on:sg CMiller WTravers GHo ahan JPa low 12/p/89 12/g/89 12/6/89 12/ /89 12p /89 DISTRIBUTION:

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NRC PDR T. Kenyon PDSLE Readin9 OGC G. Holahan E. Jordan l

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December 14, 1989

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' Project Nos. 669 676.

MEMORANDUM FOR:'

Frank J. Miraglia, Jr.

Associate Director for Inspection and Technical Assessment-Office of Nuclear Reactor. Regulation

'FROM:

James G. Partlow

. Associate Director for Projects Office of Nuclear Reactor Regulation

SUBJECT:

APPROACH FOR PRELIMINARY REVIEW 0F ADVANCED LWRS

-WITH PASSIVE SAFETY SYSTEMS In response to your meeting with W. Travers and C. Miller, PDSLE has developed an approach to be used to review the preliminary, conceptual designs of advanced LWRs that employ passive safety systems.

This approach includes (1); familiarization with the current design approaches through meetings with EPRI-and-the designers, (2) internal review and evaluation of this preliminary information, (3) preparation for a meeting away from the office to discuss the staff's conclusions with senior NRR management, and (4) development of a report summarizing the preliminary policy and technical issues resulting from the staff's review. A SECY paper will be developed to transmit the results of the staff's review and conclusions to the Commission.

In addition, the staff will discuss the results of its review with the ACRS. The report will be forwarded to EPRI and the vendors for consideration in the development of the passive EPRI Requirements Document and in the vendors' final design of these passive plants.

Enclosed is a detailed review approach including a review schedule with major milestones that need to be met by the staff in order to assure a timely and useful review. Questions and comments regarding the details of the plan should be directed to C. Miller at X21118 or T.J. Kenyon t X21120.

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Jan es G. Partlow Associate Director for Projects Office of Nuclear Reactor Regulation cc:

see next page

Enclosures:

As stated

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T2Murley NRR rec:

J. Snierek NRR G.'Holahan-

.DRSP-i G. Holahan ADR4.-

10. Miller PDSLE R. Singh-PDSLE-D.'Scaletti; PDSLE T. Kenyon-PDSLE J. Monninger SPLB~

A. Hsia.

PDSLE J. Richardson EAD

-C. Y. Cheng:

EM73-K. Wichnen EMTB L.. Marsh EMEB' P. T. Kuo

-EMEB-T.-Sullivan EMEB:

L. Reiter~

ESGB-

A.. Thadani

~ SAD M.' Rubin SAD S. Newberry.

SICB

' J. Joyce -

SICB i

F. Rosa,

-SELB

=J. Knight-SELB C. McCracken

-SPLB-R..Architzel SPLB~

J. Wermiel.

J.-Kudrick:

- SPLB SPLB R.~ Jones--

SRXB B. Grimes DRIS 4

R. Erickson-RSGB-R. Dube-RSGB F.!Congel DREP R. Barrett-PRAB L. Cunningham PRPB

T. Essig

.PRPB

J. Roe' DLPQ l

h W. Regan LHFB D. Eckenrode LHFB

.T. Gody PQEB-F. Hawkins PQEB L

E. Beckjord RES ll a '

.T..Speis RES ll

W. Houston OSIR p

W..Minners DSIR LW. Beckner SAIB B. Sheron DSR f

J. Murphy DSR

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i cc:.-M. Cunningham PRAB

H. -.Vandermolen '

PRAB E. Che111ah.

PRAB W.. Morris DRA l

-Z.1Rosztoczy DRA T.-King' ARGIB se

~J. Wilson ARDIB.

G. Arlotto DE.

- R.- Bosna k DE G. Sege-

.RPSIB' R.' Woods RPSIB-L

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ENCLOSURE y...

REVIEW APPROACH FOR 9

PRELIMINARY REVIEW OF ADVANCED LWRS WITH PASSIVE SAFETY SYSTEMS During'a May 1989 meeting with Westinghouse, NRR committed the staff to the

- performance of a licensing review of the conceptual design of the AP-600, which employs passive safety systems in its design.

Since that time, EPRI has worked toward the development of'a Requirements Document for passive designs

'and GE and CE have further developed the designs of their plants with passive safety features as well.

As a result of this interest by the industry, NRR has decided to expand the staff's review efforts to include consideration of potential conceptual safety issues associated with these plants to provide early guidance to the designers to ensure that the designs are compatible with NRC safety philosophy.

It_is important that, as a first step, we provide the NRC's initial policy and technical concerns regarding the approach the industry *is using in developing advanced LWRs that utilize passive safety systems.

Accordingly, PDSLE has developed the following approach to be used to review-these conceptual passive designs. This approach includes:

(1) familiarization with~the current design approaches through review of design information and in meetings with EPRI and the designers, (2) internal review and evaluation of this preliminary information, '

(3) meetings to discuss the staff's conclusions with senior NRR management, and (4) development of a report summarizing the preliminary policy and technical issues resulting from the staff's review. A SECY paper will be developed to transmit the results of the staff's review and conclusions to the Commission.

In addition, the staff will discuss the results of its review with the ACRS. The report will then be forwarded to EPRI and the l

vendors for consideration in the development of the passive EPRI Requirements Document and in the vendors' final design of these passive plants.

l

Background

l The review approach for the preliminary assessment of the passive plants requires familiarization with and evaluation of the current design approaches, with the ultimate goal of establishing a preliminary list of potential licensing and severe accident issues that account for the unique aspects of

.the passive plant designs. Development of such a list of issues will be more i

difficult than the previous development of a similar list for evolutionary designs since the staff will not have the direct benefit of over 20 years of operating experience in certain areas to support our review. The staff can,

'however, develop major issues from (1) evaluation of similar design features-between the evolutionary and passive designs, (2) determination of applicability of major issues that have been raised on evolutionary plants, (3) staff reviews of conceptual, passive designs, and (4) input from EPRI and the passive plant vendors.

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1The foundation of this review approach depends on several meetings with the ~

passive designs. plant vendors and EPRI to obtain information regarding passive In general, the process requires evaluation of the information

obtained from the designers in previous meetings to support the next meeting in the series. Use of such an iterative process will allow the staff to develop and refine a preliminary list of concerns that EPRI and the vendors must address for the passive plant designs.

A listing of these activities

. with'a review schedu.le is provided in Attachment 1 to outline the path that must'be followed to complete these tasks in c timel i

The role of RES in supporting NRR in the review, e.y and efficient manner, g., code development and PRA considerations, siould be carefully coordinated and defined through early and continual interaction between the offices.

Review Approach By letter. dated February 22, 1989, Westinghouse submitted copies of the plant description. report of the AP-600.

In August 1989, the staff met with

Westinghouse to discuss the conceptual design of the AP-600.

Initial review and issue-development based on the AP-600 design needs to begin in December 1989.to: support familiarization meetings with GE on the SBWR and CE on the SIR designs.

Identification of major issues and potential problems resulting from the preliminary staff review of the AP-600 should be available by late January 1990. Although GE and CE do not plan to submit a conceptual design report as was done on the AP-600, the vendors' input should provide the review staff-with so n level of additional information from which to develop a list of major r ive plant issues.

Follow-upquestions(throughtelecons)after i_

these -

ings with the vendors are expected, but should be discussed with the project inanager regarding the appropriateness of detail.

Following the familiarization meetings with GE and CE in December 1989, a decision will be l

made regarding the need for conceptual design submittals.

EPRI is planning to submit an update to Volume 1 of the EPRI Requirements L

Document, " Executive Summary," which will contain top-tier requirements and l

goals' for both evolutionary and passive plant designs in December 1989 (the current version is for evolutionary plants only).

t provides a brief list of potential issues on passive' plant p

designs that have resulted from discussions so far. This list is in no way l

meant to be-all inclusive, but is provided as a starting point to give an idea of:the types of potential issues that may result from the staff's preliminary l

review.

In addition, PDSLE has requested EPRI and the vendors to provide a L

list of major issues they have identified so far in the development of the passive plant Requirements Document as well as be prepared to address the l

questions in Attachment 2.

This information, combined with the issues identified by the staff from its reviews of the conceptual design of the AP-600 and the preliminary briefings on the SBWR and SIR, will be the topic of discussion during a meeting with EPRI in February 1990.

The passive plant vendors are expected to be represented at this meeting.

From the input from these meetings, the staff should have sufficient information to develop a preliminary list of major technical concerns and policy issues to be discussed with senior NRR management in March 1990. The staff should also be able to determine whether or not EPRI and the vendors are taking acceptable approaches to identifying and resolving major design basis L

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and severe accident concerns. The results of this meeting will then be developed into a report summarizing the preliminary policy and technical

. issues resulting from the staff's review. A SECY paper will be developed to

- transmit the results of the staff's review and conclusions to the Commission.

The staff will meet with the ACRS and the Commission as appropriate to discuss the results of'its review.

Should.the Commission have no objections, the report will be forwarded to EPRI and~the vendors for consideration in the development of the passive EPRI

. Requirements Document and in the vendors' final design of these passive plants.

It will be acknowledged with the publication of these findings that the list is intended only to be a preliminary-list of issues and, therefore, can be expected to be modified as the staff completes its review of the passive plant Requirements Document and the passive designs.

l

. Review Guidelines

. Because of the. uniqueness of the passive designs, reviewers must keep an open 1

mind regarding deviation from current NRC regulations and guidelines.

In j

performing its review, the staff should consider whether:

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1.

. the unique portions of the designs will provide safer, more reliable l

safety systems when compared to those of current generation designs even i

though they may deviate from NRC regulations and guidelines.

2.

deviations from the regulations and guidance-is acceptable, and, if not,

- why the deviations would pose a hazard to public safety.

3.

there are other possible alternatives. Staff questions in this regard should be limited to finding out if they have been considered, and, if so, why they were rejected. Although alternative suggestions by the

. staff may be helpful, they should not be required if current proposals

- are acceptable.

Report Contents The purpose of this preliminary review of the passive plant designs is to i

determine whether or not EPRI and the_ vendors are taking acceptable approaches to identifying and resolving major design bases and severe accident concerns, and to identify any "show stoppers" regarding the passive design approaches, The results of the staff's review will be documented in a report, which should l

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1.-

briefly describe unique buildings, systems, and components of the passive designs, with particular emphasis on design philosophies regarding these buildings', systems, and components which constitute major departures from current design practices.

2.

identify potential areas of deviation from NRC regulations, guidelines, and'significant past regulatory practices, i.e., lack of safety-related diesel generators or lack of active ECCS components. Note that the report need not identify all deviations, just major ones.

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identify the justifications given for the deviations by the vendors and/or EPRI and address the teceptability (to the extent possible) of v

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'these justifications. An evaluation of proposed test programs, if-provided, should also be discussed.

identify major issues and concerns _that have not been addressed by the

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proposed designs.

The report and accompanying issuance letter will acknowledge the conceptual nature of the design concepts and the need for a more in-depth review after submittal of the passive plant Requirements Document and FDA/DC applications.

Any concurrence with the design approaches will be made predicated upon the understanding that EPRI and the vendors will be required to satisfactorily address future staff concerns that may be raised during the staff's more detailed reviews of the. designs or Requirements Document chapters.

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. ATTACMENT I PASSIVE PLANT REVIEW SCHEDULE The following schedule has been developed to accommodate required review time, schedules for submittal of information and planned meetings, the impact of the holidays,- and schedules for the evolutionary plant reviews, including development of the SECY paper on proposed departure of evolutionary plants from current regulations. Note that the staff believes-that the development i

of the latter, combined with the Christmas holidays, will significantly impact

-review of _the passive plant designs until the end of the year.

Items in brackets. reflect milestones not directly related to the passive plant review that also influence this schedule.

.Date-

, Participants Milestone 02/22/89 W

.W-submits plant description repert on the conceptual.

Besign of the AP-600.

08/24/89 W

Meeting with W on AP-600.

ERR staff RES staff 10/27/89

-RES Passive plant code development meeting with RES and PDSLE-INEL.

[11/30/89].00E

[ DOE briefing to Commission on overall advanced plant program.]

12/12/89.

GE Meeting with GE on SBWR.

NRR staff RES staff r

12/13/89 CE.

Meeting with CE on SIR.

NRR staff.

RES staff l-12/89 EPRI EPRI. submits update to Volume 1 of the.EPRI L

Requirements Document.

l-

-[12/29/89]- NRR staff

[SECY paper due on proposed departure of evolutionary L

RES staff plantsfromcurrentregulations.]

L wk of 2/5 EPRI Meeting with EPRI on passive plants to discuss and Div. Dir.

clarify concerns.

L

-wk of 3/19 Murley MeetingwithseniorNRRmanagement(1-2 afternoons).

l Div. Dir.

NRR staff RES staff 3/89-4/89 PDSLE Staff prepares meeting summary / report summarizing NRR staff results of senior management meeting.

RES staff

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PASSIVE PLANT REVIEW SCHEDULE (CONTINUED)

Date Participants Milestone 4/89 PDSLE Staff meets with ACRS.

NRR staff RES staff 4/20/89 PDSLE Staff forwards SECY paper with sumary report to EDO.

5/4/89 ED0' Staff issues SECY paper forwarding report to the-Comission.

6/89 PDSLE Staff meets with Comission.

I 7/89:

PDSLE Staff transmits report to EPRI and the vendors..

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ATTACHMENT 2

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POTENTIAL ISSUES ON-PASSIVE PLANT DESIGNS The following is a list of potential issues on passive plant designs that have resulted from' cursory reviews of the passive plant designs. This list is in no way meant to be all inclusive, but is provided to give an idea of the types of_ potential issues that may result from the staff's preliminary review.

. Should passive plants be demonstrably safer than evolutionary plants? If j

,yes, what criteria should be used to demonstrate compliance with this requirement?

I'

- Does the design utilize existing rules and regulations? If not, where does.it deviate? Deviations from SRP criteria or significant past regulatory or design practice should also be identified.

Do the justifications for deviation from the Comission's regulations appear acceptable? -Are there major disagreements with the vendors' positions?

Does the design maintain / enhance the defense-in-depth concept for specific functions, i.e., such as rapid shutdown capability through redundant, diverse systems, long term decay heat removal redundancy, multiple barriers to fission product release, containment capabilities

' including ultimate capacity and heat removal functions?

- _Are the current design basis accidents still the proper selection of

-transients and accidents to use in evaluating the designs? If not, what should be added or deleted? Should more conservative DBAs be used to demonstrate that passive plants are safer than evolutionary ones?-

- Does the design minimize the potential for severe accident scenarios identified for current plants. Are there any significant accident scenarios-created by the unique design features of the passive plants.

Both prevention and mitigation of severe accidents should be considered.

What are the significant enhancements arising from the passive plant design? For example, does the design permit longer response times; does it reduce the potential for human errors; does it simplify the design?

How? Are there any design features that should be included in the 7

i-design? Why?

How should the single failure criteria be applied to passive plants? Do L

their unique design features support deviation from the single failure criteria in certain areas?

Is the single, passive RHR system on the AP-600 adequate?

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Are the single exterior containment cooling tank and system adequate?

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. ATTACHMENT.2.

POTENTIAL ISSUES ON PASSIVE PLANT DESIGNS j

-(CONTINUED) i The-increased dependency on valve operation (in lieu of active systems with pumps) to mitigate a DBA or severe accident raises potential concerns, such as Should a valve be automatically or manually actuated during an event?

What is the correct position of a failed valve for these unique designs?

i Since the-desions of certain mitigation systems depend on gravity feed, does the height of the safety injection tanks provide sufficient margir, for mitigation of an event?

Do the unique designs justify reconsideration of the Commission's policies on emergency planning and source term?

Can the safety classification of certain equipment or systems (such as the diesel generators) be downgraded due to tie unique features of, the.

plant? Conversely, should equipment be upgraded?

To what extent should the current thermal-hydraulic and containment response codes used for verification by the~NRC be modified to evaluate the passive features? Will review of the applicants' codes in lieu of such modification be sufficient?

.Do the' designs allow for easier replacement of major components, such as the steam generators?

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