ML20136G105

Forwards Addl Comments on Comparison of AP600 ERGs to Asi Evaluation Rept

ML20136G105
Person / Time
Site:	05200003
Issue date:	03/13/1997
From:	Huffman W NRC (Affiliation Not Assigned)
To:	Liparulo N WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
References
NUDOCS 9703170201
Download: ML20136G105 (4)

Text

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March 13, 1997 i Mr. Nicholas J. Liparulo, Manager Nuclear Safety and Regulatory Analysis Nuclear and Advanced Technology Division

, Westinghouse Electric Corporation i

P.O. Box 355 _l Pittsburgh, PA 15230'

SUBJECT:

ADDITIONAL COMMENTS ON C'OMPARIS0N OF AP600 EMERGENCY RESPONSE GUIDELINES (ERGS) TO~ ADVERSE SYSTEM INTERACTIONS (ASI) EVALUATION

' REPORT , .

DaarMr~.'ihirulo:j L

~'

Bylet'terND-NRC-96-4658 datedMarch5,1996,Westinghousesubmittedthe AP600 ASI Evaluation' Report (WCAP-14477). The Nuclear Regulatory Commission (NRC),Reactorisystems Branch', with assistance from a contractor from Brook-haven' National Laboratory (BNL), has; reviewed this report for consistency i against the AP600 ERGS. Based ori'this review, the staff generated comments l which were provided'to Westinghouse by NRC letter dated February 6, 1997.

BNL has now completed its review.3nd provided some additional comments that may require the ASI report andxthe ERGS'to be corrected and revised. These i comments ,are < attached as an enclosure to 'this letter. Westinghouse is i 3_ requested,to, review t.hese comments and arrange for a meeting or telephone conference to discuss"what actions are necessary for resolution. We also request that these comments be included in the open item tracking system so that the status and disposition of these items can be tracked.

If you have any questions regarding this matter, you can contact me at (301) 415-1141.

Sincerely, original signed by:

William C. Huffman, Project Manager Standardization Project Directorate Division of Reactor Program Management Office of Nuclear Reactor Regulation i

Docket No.52-003

Enclosure:

As stated cc w/ enclosure:

See next page i

DISTRIBUTION:

Docket File / PDST R/F TTMartin l PUBLIC MLSlosson TRQuay C g TKenyon- BHuffman JSebrosky 'k 'p JMoore, 0-15 B18 DJackson- WDean, 0-17 G21 ACRS (11) JLyons, 0-8 E23 ACubbage, 0-8 E23

/e evin, 0-8 E23 JBongarra, 0-9 H15 )

1*i0018 i DOCUMENT NAME: A: ERG-ASil.LTR  !

Ta seceive e copy of this document. Indcate in the hem: "C" = Copy without attachment / enclosure "E* = Copy with attachment / enclosure *N* = No copy

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0FFICE PM:PDST:DRPM SC:SRXB4$SA 9 D:PDST:DRPM l l  !

NAME WCHuf h Alevir(/// / TRQuay @ l l DATE 03/l{/97 03/ ///SV 03/A/97 l l 9703170201 970313 '

PDR ADOCK 05200003 A _

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i t Additional Comments on Comparison Between the Adverse System Interaction Report and Emergency Response Guidelines (1) Table 2.1 of the ASI report for IRWST interactions does not cross-reference Sections 2.3.3.1 and 2.3.3.2 under the columns for Recircula- 1 tion and PRHR (for the IRWST).

(2) Section 2.3.1.1 refers to an old and' outdated Rev. O of the SSAR.

(3) Section 2.2.8, Main Feedwater Pumps, discusses the potential interaction between the a MFW Pumps the SGs. Of particular concern is continuing MFW flow after a reactor trip and overfilling or overcooling the SGs. I

.The discussion in Section 3.4 (relating to Section 2.2.8) notes step 3 .

of. ERG AES-0.1, " Check FW Status." Table 3-1, under Section 2.2.8 of l the ASI report, indicates that the objective of this step is to instruct the closure of MFW control valves before establishing SFW flow to SGs (in step 3.c). However, step 3.a " response not obtained," in fact, bypasses closure of the MFW valves and goes directly to step 3.c. The objective of the step is not as clearly stated as Table 3-1 would imply.

This ERG presentation could lead to higher potential for the noted error  !

of commission.

(4) Section 2.2.9, Startup Feedwater Pumps, addresses two interactions, SFW ,

with PRHR and SFW during an SGTR event. The ASI report states that the l PRHR can not be terminated until the SFW pumps are operational and water level in hath SGs is recovered. The ERGS (e.g., AES-1.1 step 6) conflict with the ASI report in that the termination criteria are SFW in operation and narrow range level in at least one SG recovered.

In addition, discussion in Section 2.2.9 on a SGTR event notes the problem with SFW causing an overfill and an SG PORV lift. The ASI report states that SFW is automatically isolated on a high SG. water l evel . This is not consistent with the ERGS. ERG AE-3, SGTR, does not mention SFW at all, and step 3.b tells the operator to stop feed flow.

AFR-H.3, Response to High SG Level, step states " Isolate SFW to Affected SG." Neither one makes reference to the automatic isolation. Other places in the ERGS, where there are automatic isolations, have the operator " verify" the actions have occurred.

(5) Section 2.2.13, Plant Control System (PLS), discusses how the PLS provides for the control and operation of the nonsafety-related systems.

This section discusses the interactions that the PLS and pertinent nonsafety-related systems have on the various accident scenarios analyzed in SSAR Chapter 15.. These are summarized in Table 2.2 of the ASI report. Regarding section 15.4.6 of Table 2.2, it is noted that an adverse interaction is mitigated by automatic termination of boron dilution after a reactor trip. However, AE-0, for a reactor response does not mention or verify this.

Enclosure

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,i (6) Section 2.2.14, Liquid Waste Processing System (WLS), states that the WLS collects and processes radioactive waste from the RCS, including from the ADS lines to the Reactor Coolant Drain Tank (RCDT). If ADS is i actuated, RCS-V241 should automatically close tc isolate the RCDT. A i small adverse interaction is noted if the valve fails to close. The l ERGS do not check this valve closed after an ADS actuation.

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! (7) Section 2.2.16, IRWST Gutter, states the IRWST Gutter returns condensate from the containment walls to the containment sump normal operation, but ,

realigns on PRHR actuation to return the condensate to the IRWST. This  ;

i realignment is not checked in the ERGS.

(8) Section 2.3.1, Core Makeup Tanks (CMTs), deals with interactions of the l i CMTs with other passive safety systems. It mentions operator action to isolate the accumulators before the accumulator tanks empty, in order to l j prevent injection of the nitrogen gas into the reactor. Neither AE-0 i nor AE-01 contain a step to isolate the accumulators.

1 I (9) Saction 2.3.2, Accumulators, deals with interactions of the accumulators {

l with other passive safety systems. It also mentions operator action to l i isclate the accumulators before the accumulator tanks empty, in order to prevent injection of the nitrogen gas into the reactor. See comment (8)

imediately above.

(10) Section 2.3.5, Passive RHR (PRHR), states that PRHR is very important for decay heat removal in an SGTR event. Yet ERG, AE-3 for SGTRs, in

step 6.b isolates PRHR early in the ERG. These two facts seem contra-dictory.

i (11) Section 3.4, relating to Section 2.3.5.5, state that spurious actuation

of PRHR affects the RCS by increasing reactor power. They state that

! the operators would follow ERG AE-0 and eventually in step 26 transfer i to ERG AES-1.1, which in step 6 terminates PRHR. This appears to be an excessive delay in terminating the spurious actuation. Further, it is not clear that the spurious actuation would necessarily cause a safety injection signal which would be necessary to place one in AE-0 at step 26.

(12) Section 2.3.6.4, Automatic Depressurization System (ADS), discustea spurious ADS actuation. The staff's review of the ERGS has noted that the ADS is only addressed within the context of " verification of actua-tion / manual actuation backup." Unlike other " passive" safety systems (e.g., CMT) where the background documents make reference to spurious operation, the ERG background document information on ADS did not provide any guidance on isolation of ADS valves or actions subsequent to spurious operation of the ADS.

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!~ Mr. Nicholas J. Liparulo Docket No.52-003 Westinghouse Electric Corporation AP600 cc: Mr. B. A. McIntyre Mr. Ronald Simard, Director Advanced Plant Safety & Licensing Advanced Reactor Programs Westinghouse Electric Corporation Nuclear Energy Institute Energy Systems Business Unit 1776 Eye Street, N.W.

P.O. Box 355 Suite 300

Pittsburgh, PA 15230 Washington, DC 20006-3706 Mr. Cindy L. Haag Ms. Lynn Connor 4

Advanced Plant Safety & Licensing Doc-Search Associates l Westinghouse Electric Corporation Post Office Box 34 Energy Systems Business Unit Cabin John, MD 20818 4 Box 355 )

Pittsburgh, PA 15230 Mr. James E. Quinn, Projects Manager I LMR and SBWR Programs Mr. M. D. Beaumont GE Nuclear Energy

Nuclear and Advanced Technology Division 175 Curtner Avenue, M/C 165 Westinghouse Electric Corporation San Jose, CA 95125

=

One Montrose Metro 11921 Rockville Pike Mr. Robert H. Buchholz

! SL;te 350 GE Nuclear Energy Rockville, MD 20852 175 Curtner Avenue, MC-781 San Jose, CA 95125 Mr. Sterling Franks U.S. Department of Energy Barton Z. Cowan, Esq.

NE-50 Eckert Seamans Cherin & Mellott 4

19901 Germantown Road 600 Grant Street 42nd Floor Germantown, MD 20874 Pittsburgh, PA 15219 Mr. S. M. Modro Mr. Ed Rodwell, Manager Nuclear Systems Analysis Technologies PWR Design Certification Lockheed Idaho Technologies Company Electric Power Research Institute Post Office Box 1625 3412 Hillview Avenue

, Idaho Falls, ID 83415 Palo Alto, CA 94303 4

Mr. Frank A. Ross Mr. Charles Thompson, Nuclear Engineer 4 l U.S. Department of Energy, NE-42 AP600 Certification '

Office of LWR Safety and Technology NE-50

19901 Germantown Road 19901 Germantown Road Germantown, MD 20874 Germantown, MD 20874 1

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