ML16342A051

Transmits Info Re safety-related & non-safety Related Degradation Problems at Plant

ML16342A051
Person / Time
Site:	Diablo Canyon
Issue date:	04/01/1993
From:	George Minor, Sholly S MHB TECHNICAL ASSOCIATES
To:	Thadani A Office of Nuclear Reactor Regulation
Shared Package
ML16342A052	List: ML16342A051 ML20035E029
References
OLA-2, NUDOCS 9304140202
Download: ML16342A051 (30)

Text

ENCLOSURE 2 Technical Associates Consultants on Energy

& the Environment VJA FEDERAL EXPRESS 1 April 1993 Dr. Ashok C. Thadani, Director Division ofSystems Technology Of6ce ofNuclear Reactor Reguation U.S. Nuclear Regulatory Commission One White Flint North, Room 8 El 11555 Rockville Pike Rockville, Maryland 20852

Dear Dr. Thadani:

We tried to reach you today by telephone, but were unsuccessf'ul.

Accordingly, we are transmitting by Federal Express information for your evaluation and follow-up as appropriate concerning safety-related and non-safety-related cable degradation problems at the Diablo Canyon Nuclear Power Plant (DCNPP). This information was received partially &om public sources and partially &om our participation as technical consultants to San Luis Obispo Mothers for Peace in connection with the Diablo Canyon operating license amendment proceeding (construction period recapture).

The sequence ofevents involved in this issue starts initiallywith an electrical fire which occurred at Diablo Canyon on February 5, 1993. The fire involved a non-safety-related system.

Specifically, an electrical fire occurred in the DCNPP Unit 1 cable spreading room as a result ofan electrical ground in the No. 11 Circulating Water Pump. We believe that the pump was eventually restored to operability on or about February 10, 1993, and during the interim the plant operated at a reduced power level commensurate with the availability ofa single operable Circulating Water Pump.

Subsequently, by way ofa copy ofthe February 17, 1993, Region V "Morning Report", we became aware that Pacific Gas and Electric (PG&E) had pulled an unknown length ofUnit 1,12 kV circulating water pump cable that "exhibited increasing groundfault indications" ~ According to the "Morning Report" entry; I 8Matnt)ton-Avenue-Suit K, San Jose, CA 95125 Phone (408) 266-2716

~ Fax (408) 266-7149 Oq]0092-

//

4

Approximately 200fi. ofthe total 440ft. ofcable showed signs of insulator and ground conductor degradation.

The licensee suspects that afluidofunknown originfoundin the associated conduit may be the cause ofthe failure. Initiallicensee contact with the vendor (Okonite) indicates that the degradation is unprecedented and has not been seen by the industry previously.

The licensee, the vendor, and a private licensee contractor are performing analysis on the cable.

Results ofanalysis is expected to be complete by 2/27/93.

The Region is monitoring licensee evaluations.

Subsequent to this information, we received (today) &om San Luis Obispo Mothers for Peace an extract ofinformation &om a PG&E Onsite Safe Review Grou OSRG November 1992 Monthl Re ort. The extract is enclosed with this letter. In short, the OSRG document indicates that there have been three occasions since 1989 (the most recent ofwhich was apparently in November 1992) in which AuxiliarySalt Water (ASW) system 4.16 kV safety-related cable has failed, apparently due to submergence.

PG&E apparently evaluated this situation and determined that it was not reportable, apparently due to the fact that the cable's design basis does not include submergence.

We have searched the NRC's Bibliographic Retrieval System (BRS) public document computer system and can find no instance ofPG&E reporting these failures dating back to October 1992.

The fact that the cable design basis does not include submergence seems to us to beg the issue.

The facts apparently are that there have been three ASW cable failures due to a cause that PG&E does not fullyunderstand in the last three years.

The safety significance ofthe ASW system is not in dispute it is a safety-related system which serves as the functional link between safety-related decay heat removal systems and the ultimate heat sink (the Pacific Ocean).

Furthermore, the Diablo Canyon'PE results indicate that without considering the cable degradation the ASW system is responsible for about 7% ofthe internal events severe accident

&equency at Diablo Canyon.

Our concern is that the cable degradation is a new failure mode which is not reflected in the IPE, not reflected in the environmental qualification program, and not reflected in the maintenance/surveillance program, and which may make the plant more vulnerable to a severe accident, In addition, we are concerned about the attitude conve ed in PG&E's a arent decision ese otentiall commo-mode cable failures are not re ortable the N Further, the PG&E document enclosed with this letter opines that the cable degradation has resulted &om "repeated submergence over the past 20 years", (or since the 1970s) although the

plant has been in operating only since the mid-1980s. This implies a degradation ofsafety-related cable back to the period before an operating license was issued.

There are several questions about these matters which we believe need to be addressed quite rapidly:

1.

Was the NRC aware ofthe three ASW cable failures at Diablo Canyon prior to now?

2'.

Has PG&E reported the three ASW cable failures to the NRC, and, ifso, by what means?

3.

Ifnot, does the NRC agree with PG8'cE's reportability evaluation?

4.

Is the 2/5/93 Circulating Water System fire related to submergence-induced cable degradation?

5.

Is the 12 kVCirculating Water System cable degradation noted by PG&:E in February 1993 related to the 4.16 kVASW cable degradation discovered by PGEcE in 1989-1992?

6.

What assurance is there that the ASW system is and will remain operable given the observed pattern ofcable degradation due to submergence?

7.

What is the cause (or causes) ofthe submergence, and is the submergence the cause ofthe degradation, a contributing factor to the degradation, or merely a coincidence?

8.

Do PGAE and the NRC understand the nature ofthe degradation mechanism sufficiently to preclude it &om occurring in the future?

9.

Have PGkE and/or the NRC conducted inspections ofthe ASW and CWS cabling (and any other cabling potentially subject to this failure mechanism) to evaluate the status ofthe cable?

We would appreciate the opportunity to discuss this matter with you. We bring this matter to your attention as a result ofour obligation to promptly report safety concerns to the NRC, and we believe that the situation described herein is

suKciently serious that NRC should give itvery prompt attention. Ifyou have any questions, please do not hesitate to contact us at the letterhead address and telephone/fax numbers.

Sincerely, Gregory C. Minor Vice-President MHBTechnical Associates Steven C. Sholly Senior Consultant MHBTechnical Associates

Enclosures:

1. PGkE OSRG Monthly Report extract, November 1992.

2. NRC Daily Status Report, Diablo Canyon, Event 25029.

3. NRC Region VMorning Report, 2/17/93, page 3.

ENCLOSURE 1

PACIFIC GAS 5 ELECTRIC COMPANY DIABLO CANYON POWER PLANT Ons1te Safety Review Group (OSRG)

Hovember 1992 Monthly Report SUMuARY The follou<ng stems sussssrlse the osRG's ohservetlons end concerns from the Hovember meetings.

A more deta1led descript1on follows and all items that were reviewed are listed 1n Attachment l.

The recent fa1 lure oF a 4kV aux111ary saltwater pump motor feeder cable 1s the third of th1s type 1n the past three years.

2.

Seismic restra1nts for monora11 hoists, designed to prevent 1nteractions with nearby safety re1ated equipment, are not always being installed afte~ use.

3.

Two OSRG concerns From the October monthly report related to the Operability Eva1uation (OE 92-20) on CFCUs were resolved in Hovember.

DESCR?PTIOH The following 1tems were discussed by the OSRG.

Generally, where concerns exist, they have been discussed with the appropriate TRG Chairman or responsible department head and an'AR has been 1n1t1ated, 1f applicable.

1.

HCR DCI-92-EM-H054:

H1-Pot (test) on ASH PP Motor l-2 4kY Cable Fni d.

CONCERN; A recent failure of the ASM 1-2 feeder cable 1s the third DCPP documented failure of this type 1n the past three years.

The OSRG has concerns regarding reportability (1.eve outs1de design bas1s since the 40 year cable life potentia1ly is invalidated) and regarding the lack of documentation for the acceptability of potentially degraded

cable, NOTE: There are twelve total ASH pump cables, both units 1nclusive; two have experienced failures.

RESOLUTION:

Design bas1s reportab111ty was mentioned by Regulatory Compl1ance during a TRG meet1ng.

The OSRG member asked the TRG to address th1s issue at 1ts next meeting.

Preliminary 1ndication is that the condition is not reportable.

The cab'Ie design basis does not 1nclude submergence, the probable root cause.

The OSRG will continue to track th1s concern.

The concern regarding lack of documentation for the acceptab111ty of the potentially degraded condition was presented to the TRG by the attending OSRG member.

An AE to AR A0283880 will track the HCR Safety Analysis update to address this issue.

OSRG Xovember 1992 Monthly Report Page 2 of 5 The OSRG consensus is that the cable 1s not rated for long term submergence, and therefore, the cable is not fa111ng to meet submergence requirements (i.e., not outside des1gn basis).

However, degradation of the cables, due to submergence.

is a potential unrev1ewed safety question.

(The cable ts not des1gned for submergence but 1s being exposed to th1s condition.)

The Safety Analysis requested above by the OSRG should address this concern.

DISCUSSIOX; The f1rst fa11ure of a hi-pot test on th1s type of cable was 1n October 1989 on ASW PP 2-2.

The second failure was in Hay 1992 on the Bus 14E feeder.

All three insulation failures were experienced 1n the vicinity of the first c1rcuit pull box 5ust outside the turbine bu1lding.

Th1s is the low point in a long horizontal run of cable fust west of the turbine building.

The fact that water has been documented in these pull boxes, and the fact that the most recent failure occurred approximately 3 days after a ra1n shower (water found 1n ASW PP 1-2 associated pull box, 2 ft. above cable elevation),

leads to a strong pre11minary conclusion that the cable has been degraded due to repeated submergence over the past 20 years.

2.

Walkdown of Plant-Mounted Hanorail Hoists er OSRG 0 en Item 92-02 Items to Mon tor or 5

uta e

to ssure e smic s

ere e nsta ed.

CONCERX:

Seismic restraints for monorail hoists, des1gned to prevent interactions with nearby safety related equ1pment, are not being 1nstalled aFter use in all cases.

Controls to assure that plant-mounted trolleys and hoists are secured are not consistently implemented.

Mechanical Haintenance has placed steps 1n applicable work orders, at the OSRG's request.

Recently, Electrical Haintenance has been found to have the same problem.

RESOLUTION:

The OSRG initiated AR A0286084 recently on a missing ho1st seismic stop above Centr1fugal Charging Pump (CCP) 1-1.

An AE was issued to request a seismic interaction analys1s of this cond1tion and another AE was Issued to request modification of electr1cal work orders to include steps to secure ho1sts and seismic stops, Work order CO]07374 was in1tiated to reinstall the missing stop and re-stenc11 the monora11.

This issue will be followed via the AR and the OSRG's Open Item 92-02.

DISCUSSIOX:

In 1991 the OSRG issued AR A0235110 requesting that Hechanical Maintenance establish procedural guidance to ensure applicable work orders contained steps to secure monora11 ho1sts.

R1ggers who use such equipment are in the Mechanical Maintenance section.

Hechan1cal Na1ntenance responded by stat1ng that instructions would be added to RT work orders and planners would be directed to add 1nstructions to CH work orders,

Attachment 1

Ons1te Safety Rev1ew Group November 1992 Monthly Report 1.

Honconforaances The OSRG e1ther attended TRGs for the follow1ng HCRs or, 1f the TRG was not attended, rev1ewed the completed HCR package.

Spec1f1c cr1t1que comments have been prov1ded to the respons1ble Cha1rman and/or ARs have been 1n1t1ated, 1f appl1cable.

DC1-92-EH-H054:

H1-Pot (test} on ASH PP Motor 1-2 4kV Cable Fa1led.

(OSRG Surve1llance 92-055,kwr) 2.

Regulatory Correspondence HRC letter to PG&E, Hot1ce oF V1olat1on, HRC Inspect1on Report No.

92-16,.dated July 7, 1992, Chron192621.

PG&E letter to HRC, Reply to Hot1ce of V1olat1on 1n HRC Inspect1on Report Ho. 92-17.

PG&E Letter Ho. OCL-92-161, dated July 20, 1992, Chron193142.

PG&E lette~ to HRC, Response to Gener1c Letter 92-01, Rev1s1on 1,

Reactor Vessel Structural Integr1ty, PG&E Letter Ho. DCL-92-150, dated June 30,

1992, Chron192218.

3.

Miseel 1 aneous Items a)

Malkdown of plant-mounted monora1l ho1sts, per OSRG Open Item 92-02.

(Items to Hon1tor for 1R5 Outage),

to assure se1sm1c stops were re1nstal 1 ed.

(OSRG Surve1l1 ance 92-052.rcs) b)

TES evaluat1on of 'CFCU 1mbalance due to fan blade deformat1on.

(OSRG Sur ve1l 1 ance 92-054.bal) c)

OE 92-20, Rev. 1:

OE for Un1t 2 CFCUs w1th Cracked Backdraft Damper Blades.

d)

DCP H-47225:

Cycle 6 Core/SG Tube Plugg1ng

j ". ENCLOSURE 2

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GOELZER

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DICK JOLLIFFE

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EMERGENCY DECLARED

,'EVENT NUMBER:

25029

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NOTIF ICATION DATE: 02/06/93 CA NOTIFICATION TIME: 00:56

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EVENT DATE:

02/05/93

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EVENT TEXT

+ - ELECTRICAL FIRE IN 12 KV CABLE SPREADING ROON LASTING LESS THAN 10 MIN-AN ELECTRICAL FIRE OCCURRED IN THE UNIT ]

12 KV CABLE SPREADING ROOM

'DUE TO AN ELECTRICAL GROUND IN 1

OF 2

CIRC WATER PUMP MOTORS (NII).

LI C ENSE E REDUCED POWER TO 46/0 TO REMOVE f1 I C I RC WATER PUMP FROM SERV ICE (CIRC WATER PUMP IS NOT A TECH SPEC ITEM).

LICENSEE CALLED THE CALIFORNIA DEPARTMENT OF FORESTRY TO ASSIST IN FIGHTING THE FIRE.

THE FIRE LASTED LESS THAN 10 MINUTES AND IS PRESENTLY OUT.

SMOKE HAS BEEN Cl EARED FROM THE ROOM THERE WERE NO PERSONNEL INJURIES DURING THE POWER REDUCTION, THE DIGITAl. ROD POSITION INDICATIONS DID NOT FOLLOW THE CONTROL ROD INDICATORS AS CONTROL RODS MERE INSERTED INTO THE

CORE, LICENSEE DECLARED CONTROL BANK 'D'9 CONTROL RODS)

INOPERABLE.

TECH SPEC 3.1.3,1 REQUIRES LICENSEE TO RESTORE CONTROL BANK 'D'O OPERABLE STATUS WITHIN 72 HOURS OR TO PLACE UNIT I IN AT LEAST HOT SHUTDOWN MODE WITHIN THE FOLLOMING 6 HOURS.

I 8

C TECHNIClANS ARE INVESTIGATING THE CAUSE AND 'DETERMINING CORRECTIVE ACTIONS.

I LI C ENSEE NOT IFI ED STATE AND LOCAL OFF I C IALS AND THE NRC RES IDENT INSPECTOR

,'ND WILL ISSUE A PRESS RELEASE.

I L IC ENSEE IS MAKING AN ENTRY INTO THE ROON TO DETERNIHE THE CAUSE AND EXTENT OF DAMAGE.

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• * ~ UPDATE AT 0216 SY GOELZER ENTERED BY HOO JOLLIFFE ~ *

• AT 2232

{PST)

ON 02/05/93, LICENSEE TERMINATED THE UNUSUAL EVENT.

I LICENSEE DETERMINED THAT THE ELECTRICAL GROUND IN Nil CIRC WATER PUMP ROTOR CAUSED THE LOAD BANK IN THE 12 KV CABLE SPREADING ROON TO OVERHEAT BURNING PAINT, DIRT%

AND DUST IN THE ROON.

THERE WAS NO ACTUAL FLANEUR ONLY SHOKE IN THE ROON CAUSED THE F!RE ALARN.

NO EQUIPMENT IN THE ROON WAS DAMAGED.

LICENSEE NOTIFIED STATE AND LOCAL OFFICIALS AND THE NRC RESIDENT INSPECTOR OF THE TERNINATION OF THE UNUSUAL EVENT.

HOO NOTIFlEO RSDO MENSLAMSKI, NRR EO RICHARDSON, FENA STINEDURF,

REGION V HORNING REPORT Lt cans en/Fac IIity:

Pac sfic Gas 4 Electric Co.

Diablo Canyon Avsla Beach.California Dacacts:

SQ-275 PWR/W-4-LP PAGK 3

Nottfl.cation:

FEBRUARY 17.

1993 HR Nuntcrt 5-93-OQ10 Date:

02/17/93 TKLKPtlONK CALL FROH RI Sublcct:

CIRCULATING MATER PUHP POWER CABLE DEGRADATION-UPDATE TO EVENT REPORT NUHBER 25029 Reportable Event Number:

N/A Discuss ion:

THE TWELVE KV CIRCULATlNG MATER PUHP CABt.E THAT FXHIBITED INCREASING GROUND FAULT INDICATIONS MAS DKKNKRGIZKD AND PULLED FROH ITS UNDERGROUND CONDUIT. APPROXIHAIKLY 200 FT.

OF THE'OTAL 440 FT.

OF CABL'E SHOWED SIGNS OF INSULATOR AND GROUND CONDUCTOR OEGRADATlON.

THE LICENSEE SUSPECTS THAT A FLUID OF UNKNOWN ORIGIN FOUND IN THE ASSOCIATED CONDUIT HAY BE THE CAUSE OF THE FAIl.URE. INITIAL LICENSEE CONTACT MITH THE VENDOR (OKONITE INDICATES THAT THE DEGRADATION IS UNPRECEDENTED AXD HAS NOT BEER SEEN BY THK INDUS1RY PRKVIOUSLY.

THE LICENSEE.

THE VENDOR AND A PRIVATE LICENSEE CONTRACTOR ARE PERFORHlNG ANALYSIS ON THE CABLE. RESULTS OF ANALYSIS IS EXPKCTKD TO BE COHPLETK BY 2/27/93.

THK REGION IS MONITORING lICENSEE EVALUATIONS. UNIT 1 HAS RESUHED FULL POWER OPERATIONS.

Ra5ional Action:

N/A Coatact W. An9 (5101975-0310

APR-2-9S FR I 16 2T MHS TECHNICAL ASSOC ENCLOSURE 3

FAX TRANSMIYYAL MHB TECHNICAL ASSOCIATES 1723 Hamilton Avenue, Suite K San Jose, CA 95125-5428 YEL: (408) 266-2716 FAX: (408) 266-7149 DATE:

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FRI 16:28 NHB TECHNICAL ASSOC 4882667 1 49 P. 82 PACIFIC GAS E

ELECTRIC COMPANY DIABLO CAHYOH POWER PLANT Onsite Safety Review Group (OSRG)

December 1992 Monthly Report

SUMMARY

The Following items summarize the OSRG's observations and concerns from the meetings for this month.

A more detailed description follows and all items that were reviewed are listed in Attachment 1.

1.

A recent NCR on Diesel Fuel Oil piping corrosion did not adequately address two earlier ARs from February 1990 that identified the same problem.

The HCR does not'ddress the need for corrective actions for past failures to identify and resolve this problem.

2.

There is an apparent inconsistency between administrative procedures governing reportabflfty oF seismic hazards that are corrected on the spot.

3.

In response to a Nuclear Safety Oversight Cornnfttee (HSOC) request.

the OSRG examined current operability evaluations for potential interrelationships.

Such 1nterrelatfons could impact accident analyses.

4.

A failure of the speed reference input to the Unit 2 main turbine digital-electrohydraulic controls (DEHC) occurred on 8/31/9l.

A year

later, an NCR resulted, fn part, due to the same problem in Unit l.

However, after this second occurrence, the investigation and testing was a ma)or effort.

The thoroughness and determination of the TRG members involved fn this effort were noteworthy, 5.

The NRC suggested possible similarities between a heavy loads rigging incident and an earlier incident.

Because DCPP took exception to this, any lessons to be learned may not be recognized, DESCRIPT ION The Following items were discussed by the OSRG.

Generally, where concerns exist, they have been discussed with the appropriate TRG Chairman or responsible department

head, and an AR has been initiated, if applicable.

1.

NCR DC2-92-TN-N028:

Corrosion of Auxiliary Salt Mater (ASM) Annubar

~pp F

1 Dl1 (DFD) Dipl 1

CONCERN:

The XCR dfd not adequately address two February 1990 ARs which identified DFO pfp1ng corrosion.

Although an NCR action item provided for an investigation of the details associated with these

ARs, the HCR does not provide corrective actions to address this failure of the problem resolution process to,preclude subsequent DFO (and,

possibly, ASM) piping and pipe support corrosion.

APR-2-9S FRI 16 29 NHB TECHNICAL ASSOC 4882667 I 49 P. 88 OSRG December 1992 Monthly Report Page 2 of 7 RESOLUTION:

The OSRG's concerns were discussed with the TRG chairman.

The need for additional corrective actions to address these concerns will be discussed 1n an early January 1993 TRG for this NCR.

Addit1onally, th1s HCR w111 be 1ncluded in OSRG OI 89-14 regarding ineffective correct1ve actions, and in OI 89-25 regarding ARs w1th improper gE determ1nations.

D1SCUSSIOH:

On 6/18/92, a hole about one and one-half inches 1n diameter was found in the annubar piping for ASM train 2-2.

Corrosion was also noted in the annubar p1ping of the other ASH tra1ns.

Subsequent 1nspect1ons of other p1ping 1n the Un1t 2 west buttress pipe trench on 6/2l/92 revealed corrosion of the two cardox lines and DFO train O-l piping, On 7/2/92, ultrasonic test1ng of the DFO train 0-1 piping revealed one location that was below the minimum wall th1ckness requirement.

An Engineering evaluation revealed that the OFO piping would still have performed its intended function, A voluntary LER (1-92-006-01) was subm1tted for the DFO piping degradation.

The TRG root cause for the DFO and ASW p1ping degradat1on was general corrosion due to breakdown of the coal tar coating.

Th1s exposed the p1ping to standing water and the saltwater/air environment.

Standing water seeping through the coating resulted in p1ping corrosion, especially at the air/water 1nterface.

As the 1ron oxide formed and

expanded, the coal tar coating was further degraded, and the corrosion spread.

The standing water in the trench was due to inadequate

dra1nage, caused by flow blockage by pipe supports and external debris.

Contributory causes identified by the TRG were:

l) inadequate surveillance and 1nspection procedures which did not provide instruction for identification of corrosion, and 2) inadequate initial application and maintenance of the coal tar coat1ng on the underside of the DFO and ASM pip1ng.

The TRG corrective actions 1nclude the development and implementation of a program to inspect and repai~ or replace the remaining areas of corrosion on DFO and cardox p1ping and supports.

The program will also include 1mprovements 1n the surveillance

program, the protective

coatings, and drainage of the p1pe trench.

Addit1onally, standing water in the trench will be minimized as part of th1s program.

To address the gener1c plant concern of corrosion, a task force was formed. It w111 develop and implement a comprehensive program for actual or potential corrosion problems in other safety related pip1ng.

0

4982667149 P

84 OSRG Oecember

]992 Ho>>thly Report Page 3 of 7

The d1 positioning of the 199n ARs resulted in repairs to the affected corrosion areas.

Also, an 1ncvease was made in the frequency of the DFO system leak inspect1on surve1llance (STP H-91).

However, STP H-91 (as noted 1n one HCR contributory cause) did not specif1cally address corros1on problems, nor did the STP require 1nspection of all DFO trt.nsfer piping or the coated ASM pip1ng in the Unit 2 west buttress p1pe trench.

A gE was not 1n1tiated for either of the ARs, nov was HECS requested to evaluate the s1gnificance of corrosion on coated piping.

Thus, the previous corrective actions were ineffective.

2.

Administrative Procedure AP C-IOSI; Seismically Induced System Inl,eractTon Prograe glglP)

Rev ew of iiousekeeping Act1v1ties COXCkRX:

An HRC Resident Inspector revealed an apparent 1nconsistency between administrative procedures.

The one governing reporting of seismic hazards disagrees w1th those governing problem resolution and operab111ty evaluations.

RESOLUTIOH:

Action Request AO288854 was in1tiated by the OSRG and routed to Quality Control.

It details the apparent inconsistency between AP C-IOSI and procedures C-12 and C-29 (Problem Resolution and Operability Evaluations, respectively).

The Quality Cont~ol section is responsible for C-10S1 ard its rev1sion.

DISCVSSIOH:

Mhen a SISIP pvoblem 1s found, it may be corrected on the spot.

The applicable procedure for plant housekeeping act1vities is AP C-10S}.

This~rocedure allows roblems togo undocumented and i~irr '

a i ii t ii HIIWl&

opera e and the problem is discovered and corrected so quickly that any potential inoperability is momentary, OCPP's position is that any potential operability concern begins at the time of discovery.

However, this SISIP policy appears to be 1n confl1ct with APs C-I2 (Problem Resolution) and C-29 (Operab111ty Evaluations).

Both procedures require an AR to be wr1tten and thegast ogepabiTfty and reporTab1Ttt~o"'h~~au~t~ed

. uch,~auditions siior regula,regi}ruing to %tie HK, even t7 easi.ly Xt'.a~died.

SISIP haiagh awy~lace-the plant in an unenb~e co'nolition. and ~ossf97 outside of the des1gn bas1s.

D1scuss1ons on t~gtWer are contTnuTiig, 3.

AR A0283432~AE-9:

Interrel ationsh1ps Between Operabi1 1 ty Evaluations PEs)

COXCERN:

The OSRG raised a concern that mult1ple OEs could create condit1ons adverse to nuclear safety in unrecognized ways.

RESQt.UTIOH; The HSOC requested that the OSRG look into potential inte, relationships between current OEs.

An OSRG member reviewed the current'fs and categorized thoir effects on F SAR Chapter 15 Condition III and IV events.

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n kp*~4 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON. D.C. 20555-0001 March 30, 1993 Docket Nos.

50-275 and 50-323 LICENSEE:

Pacific Gas and Electric Company (PGEE)

FACILITY: Diablo Canyon Nuclear Power Plant, Units 1 and 2

SUMMARY

OF MARCH 10, 1993 PUBLIC MEETING TO DISCUSS THE LICENSEE'S PROPOSED EAGLE 21 PROCESS PROTECTION SYSTEM UPGRADE AND RESISTANCE TEMPERATURE DETECTOR (RTD)

BYPASS ELIMINATION On March 10,

1993, the NRC staff met with the Pacific Gas and Electric Company (PG&E or the licensee) in Rockville, Maryland to discuss the issue stated above.

A list of the attendees present at the meeting is enclosed.

A copy of the licensee's presentation slides is also enclosed.

The proposed Westinghouse Eagle 21 upgrade at Diablo Canyon would replace the Westinghouse 7100 analog process protection equipment with digital equipment that is intended to improve the reliability and availability of the reactor protection system.

The proposed RTD bypass elimination modification involves removal of all reactor coolant system hot and cold leg bypass manifolds and associated piping and valves.

Dual element RTDs would be installed in thermowells in the hot and cold legs to provide the necessary reactor coolant temperature information.

The meeting was held to discuss these two modifications that are the subject of a license amendment request (LAR 92-05) submitted to the staff by PGLE on September 21, 1992.

The licensee described the implementation of both modifications at Diablo Canyon.

The Westinghouse Eagle 21 upgrade was discussed first.

The licensee stated that testing of electromagnetic and radio frequency interference (EHI/RFI) at the site had been successfully completed and that they would submit a report to the staff on the results by March 31, 1993.

The licensee indicated that the procedures used for the EHI/RFI testing and the format of the final report would be virtually identical to those used at Zion.

The licensee also stated that the software to be used at Diablo Canyon was a subset of the software used at Sequoyah which was previously reviewed by the staff.

The staff mentioned cross calibration problems experienced at Sequoyah regarding temporary test setups without qualified isolation.

The following is a summary listing of issues that the staff requested the licensee address in order to support the staff's review:

Diversity between Eagle 21 and Anticipated Transient without Scram Mitigation System Actuation Circuitry (AHSAC) (software)

Defense in depth timing and quality as applied to the Emergency Operating Procedures Input/Output configuration Factory acceptance test results Disposition of comments on the functional requirements gmtI', ggP ~Pj@ O'II V/f~