ML20044F770

Intervenor San Luis Obispo Mothers for Peace Second Set of Supplemental Interrogatories & Requests for Production of Documents to Pge Cable Failures at Diablo Canyon Nuclear Power Plant.* W/Certificate of Svc.Related Correspondence

ML20044F770
Person / Time
Site:	Diablo Canyon
Issue date:	05/21/1993
From:	Culver N SAN LUIS OBISPO MOTHERS FOR PEACE
To:	Atomic Safety and Licensing Board Panel
References
CON-#293-13996 92-669-03-OLA-2, 92-669-3-OLA-2, OLA-2, NUDOCS 9306010029
Download: ML20044F770 (15)

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gg @RRESPONDENCE DE-M ED

. ev UNITED STATES OF AMERICA 93 y,.,"" gg o n.f g NUCLEAR REGULATORY COMMISSION ATOMIC SAFETY AND LICENSING BOARD In the matter of Pacific Gcs and Electric Company Docket Nos. SD-27S-OLA-2 Dichlo Canyon Nuclear Power Plant S0-323-OLA-2 Units 1 and 2 ASLSP No. S2-669-03-OLA-2 Facility Operating Licenses No. DPR-80 and DPR-82 Mcy 21, 1993 I

Intervenor San Luis Obispo Mothers for Peace l

Second Set of Supplemental Interrogatories and Requests for the Production of Documents to Pacific Gas and Electric Company Re: Cable Failures at Diablo Canyon Nuclear Power Plant i

i Pursuant to 10 CFR 2.740b, Intervenor Son Luis Obispo Mothers for Pecce C"SLOMFF"] hereby propounds written interrogatories and requests for i

the production of documents hereto, to be answered by licensee Pccific Gas l

cnd Electric Company C"PGSE"] under octh cr offirmation according to the i

schedule established by the Atomic Screty and Licensing Board.

The responses to the interrogatories should conform to the instructions and definitions contained in Attochment A to the First Set of Uritten Interrogatories and Requests for the Production of Documents to PGSE CFebruary 15, 15S3].

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Respectfully Submitted, 3

Nancy alver, President Son Luis Obispo Mothers for Pecce P.O. Box 164 Pismo Beach, CA S3499

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9306010029 930521

{DR ADOCK 05000275

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1.

Provide a copy of the specifications or other similar documentCs3 under which PG&E purchased the SkV cable for which three failures are described f

in Dicblo Canyon Nuclear Power Plant C"DCNPP"] Licensee Event Report r

("LER"3 50-275/S3-005 CApril 23, 19933.

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2. Provide copies of any " Nuclear Notebook" entries generated by PG&E concerning the 4kV cable failures described in LER 50-275/S3-005.

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3. Provide o copy of any documentation prepared by Okonite Cor others) i which describe the design service conditions for the SkV cable for which I

three failures are described in DCNPP LER 50-275/S3-005.

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4. Describe how the octual service conditions for the os-installed MkV cable compare or contrast with the design service conditions os described 1

i by the cable vendor.

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5.

Identify and provide copies of any precedures which PGSE utilizes to

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ensure that the design service conditions of the MkV cables for the i

e Auxilicry Scit Water C"ASW"] system cre not exceeded in octual service.

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Identify and provide copies of any quality assurance and/or quality f

I control oudits Cor similar documents such as quality surveillonces or i

observations) which have been performed on the installotion, operation, l

i and/or maintenance of the SkV ASW system cable.

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7. Indiccte whether PG&E believes that the three ASU 4kV cable failures 1

described in LER 50-275/93-005 have the some root and contributing causes.

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. Describe in detail the bases for PG&E's beliefs in this regard, and if the l

root and contributing causes are believed to be the some, please address l

l whether Cand why or why not] PG&E believes the three failures should be l

considered to be '~ common mode" failures Ewithin the meaning of "ccmmon mode

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failures" os that term is generally used in the practice of reliability and r

't risk cssessment].

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8.

Identify the nature of any lubricant employed in the installation'of the 4kV A5U system cable for which three failures are described in LER 50-i i

275/93-005, and indicate whether the use of this lubricent was opproved by i

i the cable vendor.

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Indicate whether, for any of the three 4kV A5U system cable failures I'

described in LER 50-275/93-005, the outer neoprene jocket for the' cable was e

observed to be degraded in any way Ce.g.,

chraded, scraped, peeled, etc.3.

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10. Describe the design and function of the cable pull box sump pumps mentioned on page 3 of 19 of LER 50-275/93-005.

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11. Identify each occasion on which any of the cable pull box sump pumps f

mentioner on page 3 of 14 of LER 50-275/93-005 have been found to be inoperable, and provide copies of any reports which were generated to I

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1 document these instances of inopercbility.

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12. Page 3 of 14 of Ler 50-275/93-005 indicates that the ASW system 4kV cables are installed in duct bank conduits with 480V power cables, 120U oc control cables, 125U de control cables, and instrument cables.

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indicate whether any of these additional cables are ossociated with the-ASW i

system and, if so, whether these additional cables have experienced any j

degradotion ond/or failures.

Please provide copies of any reports i

documenting such failures.

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13. Provide copies of all reports received from Okonite ond/or the PGBE l

Testing and Ecological Services C"TES"3 Laboratory concerning the 4kV ASW j

system cable failure which occurred on October 29, 1989, os reported in LER

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50-275/005, page 4 of 14.

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14. Provide copies of all reports received from Okonite and/or the PGBE TES Laborotary concerning the MkV ASW system cable failure which occurred on May 3, 1992, os reported in LER 50-275/93-005, page 4 of 14.

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15. Provide copies of all reports received from Okonite., Cable Technologies i

Laboratory C"CTL"), and/or the PG&E TES Laboratory or any other entity or 1

i personts3 concerning the 4kV ASW system cable failure which occurred on October 31, 1992, os reported in LER 50-25/93-005, pages 4-5 of 14.

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16. Provide copies er any other reports concerning the 4kV ASW cable l

1 failures which occurred on October 29,,1989, May 3, 1992 ond October 31, l

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.1992.

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17. Provide copies of any PG&E documents which comment on the reports generated by Okenite, CTL, and/or the PG&E TES Laborotory, or any.other entity or personts] concerning the 9kV ASU system cable failures which occurred on October 29, 1989, May 3, 1992, and October 31, 1992, os reported in LER 50-275/93-005, pages 4-5 of 14.

18. Describe why the DCNPP Unit 1 Bus 14D MkV cable is considered by PG&E to be "non-screty-related" os identified in LER 50-275/93-005, page -7 of 14.

19. Indicate whether PG&E believes that the 4kV ASW system cables which foiled on October 29, 1989, and October 31, 1992 Cos identified in LER 50-275/93-005, pages 4-5 and 7 of 14], were safety-related, and, if not, please explain in detail why not.

20. Explain in detail the bases for PG8E's belief that the 4kV ccble failures discussed in LER 50-275/93-005 were not caused by "monufacturing defects" Cpage B of 143, and provide copies of the documents which fcrm the bases for PG&E's belief.

21. Provide copies of the documentCs3 which describe the SkV ASW system cable design basis for wet ond/or dry conditions os discussed in LER 50-

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275/93-005, page 8 of 14.

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22. Explain in detail the bases for PGBE's belief that SkV cable failures discussed in LER 50-275/93-005 were not caused by " chemical degrodotion"

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t Cpoge 8 of.143, and provide copies of the documents which form the bases for PG&E's belief.

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23. Provide o copy of the root cause evoluotion for'the 4kV ASW system cable failures [os discussed in LER 50-275/93-0053.

If the root cause evoluotion is not now completed, please provide notes or drafts that hove' been completed.

In addition, please provide o copy of the root cause evoluotion when it is completed.

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24. Describe in detail the bases for PG&E's opinion, os expressed on page-l l

10 of 14 of LER 50-275/93-005, that "The ground detection system, os well j

os additional control room indication Ci.e.,

red / green lights ossociated t

with the motors), provide sufficient time to identify and correct a problem I

prior to another failure cousing a portion of a mutually redundant system j

from becoming inoperable."

Please provide copies of all documents which 4

t discuss this issue and/or which form all or port of the basis for PG&E's 1

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opinion.

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25. Provide copies of all nonconformance reports ossociated with SkV cable failures in the ASW system at DCNPP, Units 1 and 2.

If some of these reports have already been provided to SLOMFP, please identify them by number and date, i

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25. Explain how the ASW system at DCNPP Units 1-ond/or 2 con be operated if i

the 120U oc control or instrument circuits are lost (see page 11 of 14 of 1

LER 50-275/93-0053.

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27. Please indicate whether the ASW pumps can be operated "for o limited i

time" with a ground on a MkV cable, and, if so, please identify the length of time and the number of cycles of operation for which such operation-is' possible.

28. At page 10 of LER 50-275/93-005, PG&E states that "In all cases, DCPP e

i hos ground detection clarms that provide indication that c potential cable l

problem exists."

Please indicate whether there are any safety-related l

electrical power, control, or instrumentation cables which are not equipped with ground detection clorms, and, if so, please identify the effected; components and trains of systems, i

29. At page 10 of.LER 50-275/93-005, PG&E states that "The 12kU, SkU, and' 480U systems have high-resistance grounding, which allows continued.

cperation for c limited time in the event of a single-line-to-ground 1>

fcult."

Please quantify, for each type of cable, what is meant.by " limited.

time."

In each cose, what is the longest time that the cable would need to j

i operate during on occident?

Please describe the basis for your answer.-

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30. Identify all other safety-related applications of the SkV cable that is i'

described in LER 50-275/93-005.

I a) Are the cables in these opplications submerged at any time?

If so,

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please describe any and all-steps' that have been tok:

'to verify their

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b) Are any of these safety-related applications of SkV cable subject i

to the requirements of 10 CFR 50.49 due to their location in a harsh accident environment?

If so, please describe all steps that have been j

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r taken to determine whether the environment in which they have been

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i installed C1.e.,- temperature, radiction, humidity], is within the bounds of the conditions to which the cable was aged for purposes of environmentol-t qualification, or which were assumed for purposes of environmental qualification.

Please supply copies of all records compiled in mcking this determination.

j c3 For all such coble located in a harsh environment, please discuss f

i whether ground detection clorms are used.

If so, please discuss the extent to which they would be effective in predicting cable failure in the event.

i of a LOCA.

31. Identify all other safety-related opplications of the 12kV cable that f

is described in LER 50-275/93-005.

o] Are the cables in these opplications submerged at any time?

If so, l

i please describe-any and all steps that have been token to verify their i

operability.

b3 Are ony of these safety-related applications of 12kV cable subject i

t to the requirements of 10 CFR 50.49 due to their locotion in a harsh occident environment?

If so, please describe all steps that have been token to determine whether the environment in which they have been I

installed C1.e., temperature, radiction, humidity), is within the bounds of- ;

the conditions to which the cable was cged for purposes of environmental qualification, or which were assumed for purposes of environmental l

qualification.

Please~ supply copies of all records compiled in making this determination.

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c3 For all such cobie located in o harsh environment, please discuss whether ground detection clarms are used.

If so, please discuss.the extent b

to which they would be effective in predicting ccble fcilure in the event of a LOCA.

3P. In NRC Information Notice No. 89-30 CMorch 15, 19'89'J, the NRC clerted licensees to "patentici problems resulting from high temperature environments in crecs that contcin safety-related equipment or electrical cables."

Jda at 1 (copy attached].

The NRC noted that "It is important for licensees to be cwore that there are crecs within the plant where the local temperature may exceed equipment qualification specifications even when the bulk temperature, as measured by a limited number of sensors, is indicoting that it is lower than the qualification temperature."

Jd, at 3.

SLOMFP seeks to determine, for any safety-related opplications of SkV cable or 12kV ccble in o hcrsh environment, whether PG&E mecsures lecc1 temperature with reasonoble cccurccy.

Please describe PG&E's method for mecsuring the temperature to which scFety-relcted ccble is subjected.

Into what zones, if cny, is the containment broken for purposes of temperature measurement?

Plecse provide the results of cl1 such tempercture measurements.

Please provide the results of cny compcrisons between these l

temperature measurements and environmentc1 qualification specificctions for ccble.

33. Please provide copies of any documents which describe PG&E's evoluction 1

of or response to NRC Information Notice 89-30 C"High Temperature d

Environments at Nuclecr Power Plants", narch 15, 19993.

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34. At pcge 4 of 14 Of LER 50-275/93-005, PGSE states that the testing Icborcteries " determined the [ October 29, 1989] failure to be on isolated

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event."

Please explain whether PG&E now ogrees with these ossessments,-ond 'l provide the basis for PG&E's current beliefs and conclusions in this

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regard.

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35. In LER 50-275/93-005 CpoGe 11 of 14], PG&E stated that, "Furthermore,-

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i since the failures have been separated in time, and diagnostic examinations v

of the failed cables and the additional 'non-foiled' cables show no l

evidence that additional failures are imminent, the probabilityfor o design basis occident followed by a rondom MkV failure is considered to be very low."

Did the laboratory and visual examinations of the " failed" and "non-

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failed" cables show any differences?

If so, please describe the differences in detail.

If not, please explain how PG&E con reach the

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conclusion quoted above.

Morevover, please explain in quantitative terms l

what PG&E means by "very low" in the context of the probability of a design basis occident followed by a rondom 4kV cable failure.

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35. Provide copies of the documents which describe the " formal preventive maintenance progrom" which hos been established for the " sump pumps and drains immediately outside the-turbine building" CLER 50-275/93-005, page 11 of 143.

37. In LER 50-275/93-005 Cpoge B of 14], PG&E indicates that it mode inquiries of other nuclear power plants regarding medium voltage EPR insulated cable failures.

Please provide copies of documents which describe the substance of those inquiries, or, if no such documents are I

ovoilable..please identify whether any other failures have occurred ond, if

l so, please describe the circumstances (type of cable, system offected,

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I plant name, - date, - method of discovertj of the failure, and the ossessed root I

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cause for the failure].

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Abdtmed 2.

1 UNITED STATES NUCLEAR REGULATORY COMMISSION i

OFFICE OF NUCLEAR REACTOR REGULATION WASHINGTON, D.C.

20555 March 15,1989 NRC INFORMATION NOTICE NO. 89-30: HIGH TEMPERATURE ENVIRONMENTS AT EUCLEAR POWER PLANTS Addressees:

All holders of operating Itcenses or construction permits for nuclear power reactors.

Purpose:

This information notice is being provided to 41ert addressees to potential problems resulting from high temperature environments in areas that contain safety-related equipment or electrical cables.

It is expected that recipients will review the information for applicability to their facilities and consider actions, as appropriate, to avoid similar problems.

However, suggestions con-tained in this information notice do not constitute NRC requirements; therefore, no specific action or written response is required.

Description of Circumstances:

In November 1988, while Duane Arnold Energy Center (DAEC) was shut down for refueltag, the licensee for DAEC discovered.1 pinhole leak, 2 through-wall cracks, and 30 flaw indications on the control rod drive (CRD) insert lines inside the drywell. The defects were caused by externally induced chloride stress corrosion cracking. The area near the defects contained Rockbestos Firewall !!! radiation, cross-linked, polyethylene-insulated, electrical cable with a Hypalon (Neoprene Chicroprene) jacket.

been degraded by exposure to local drywell temperatures in excess of 270*F.Th When the damaged electrical cable was replaced loose degraded insulation lodged in the conduit and the field junction box.

Moisture from steam leaks condensed in and dripped through the conduit onto the CRD piping. The conden-sate contained chlorides that were leached from the insulation lodged in the conduit and the junction bpx, There are several areat at a reactor facility where degradation of cables and leaching of chloride may occur because of high temperature and humidity.

In addition to the drywell, the licensee for DAEC also found indications 'of chlorldes teaching on the steam tunnet.

During a refueling outage in November 1988, the Itcensee for Dresden Unit 2 discovered evidence that paint inside the upper region of the drywell had been exposed to elevated temperatures.

Further investigation revealed that the Limitorque operators on the steam supply vaivas to the hfgh-pressure

IN 89-30 Parch 15, 1989 Page 2 of 3 coolant injection system and the isolation condenser (located in the same ares) had indications of exceeding their environmental qualification (EO) design Grease samples taken from these valves showed significant degra-tempera ture.

Other cation, and the lower main bearing of one valve operator was demaged.

equipment affected by the high temperature included two vessel head vent valves Also, the electrical insulation en about and a standby liquid centrol valve.The root cause for the elevated temperature at 50 cables was cracked.

was attributed to a deficiency in procedures that resulted in the ventilation ducts in the upper region of the drywell being left closed for about 18 months while the plant was in operation.

In August 1987, the NRC became aware that Arkansas Nuclear One, Unit 1 (ANO-1),

had probab13 operated since it was licensed in 1974 with containment temper-The bulk average temperature was roughly atures ranging from 90'F to 180*F.

140'F.

Safety-related electrical equipment is environmentally qualified to operate at temperatures up to 120*F.

Also, design basis accident scenarios temperature of 11o*r.

over had been analyzed assuming an initial containunt tue years, Ine 11censee for ANO-1 attempted to reduce the high containment temperature by installing improved nsulation on the reactor coolant system i

and by acid cleaning of the chillers used for the containment ecoling units.

These efforts resulted in a very limited temperature reduction.

Discussion:

In the boiling-water rwactor events described above, elevated drywell temper-Electrical ature was responsible for degradation of safety-related equipment.

cables are vulnerable to degradation when exposed to high temperatures that exceed their design EQ temperature even for a short period.

Regarding the DAEC event, the elevated temperature along with high humidity led to the degradation of safety-related components.

In the ANO-1 event, the higher local temperatures exceeded some of the EQ temperatures for some of the safety and non-safety equipnent and components.

Also, the higher bulk temperature exceeded the ambient temperature assumed in some of the accident analyses.

Three of the analyses that were affected were:

1. The reactor building peak pressure analysis.

2. The inadvertent initiation of the containment spray system analysis.

3. The internal containment subcompartment differential pressure analysis.

There has been a history of reports since 1982 of boiling-water reactors (BWRs) and pressurized-water reactors (PWRs) experiencing excessive heat load problems On within the drywell.od localized high temperature areas within containment.

the-NRC issued Temporary Instruction (TI) 2515/98, "Information June 30. 1988, The of High Temperature Inside Containment /Drywell in PWR and BWR Plants."

objective of this T1 was to determine whether or not high containment or drywell T

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4 IN 89-30 March 15, 1989 Page 3 of 3 temperatures were a plant-ssecific problem or generic to all PWRs and BWRs.

Preliminary findings from tie T! showed that:

1. BWRs, especially Mark I and !! containments, routinely cperate very close to their EQ temperature limit.

2. In the drpells of BWRs there may be substantial temperature gradients I

(i.e.,100'F or more) that may or may not be detected depending on the location of instrumentation and circulation of the drywell air.

3. The BWR drywell head region seems most susceptible to high temperature, i

4. Some PWRs experienced high containment temperatures but the licensees failed to recognize the safety significance and take corrective actions.

It is important for licensees to be aware that there are areas within the plant I

where the local temperature may exceed equipment qualification specifications even when the bulk temperature, as measured by a limited number of sensors, is indicating that it is lower than the qualification temperature.

No specific action or written res sonse is required by this information notice.

If you have any questions about tais matter, please contact one of the technical contacts listed below or the Regional Administrator of the appropriate regional office.

W b[fW' Charles E. Rossi, Director Division of Operational Events Assessment Office sf Nuclear Reactor Regulation Technical Contacts:

R..Anand. NRR (301)492-0805 h

T. Greene. NRR (301)492-1176

Attachment:

List of Recently Issued NRC Information Notices i

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Certificate of Service 93 MP' 26 P2 :49 I hereby certify that copies of the foregoing Intervenor Son Luis Obispo Mothers for Peace Second Set of Supplemental Interrogatories and; Requests for the Production of Documents to Pacific Gas and Electric Company Re:

Cable Failures at Diablo Congon Nuclear Power Plant hcve been served upon the following persons by U.S.

mail, first c1 css or by FAX as indicated C*).

Office of Ccemissicn Appellate Administrative Judge Adjudicction Chcrles Bechhcefer, Chairmon U.S.

Nuclect Regulatory Ccmmission Atomic Scfety cnd Licensing Secrd Ucshington, DC 2C555 U.S. Nuclear Regulatory Commission Ucshington, DC 2C555 Administrative Judge Jerry Kline Administrctive Judge Atomic ScFety and Licensing Board Frederick J. Shon U.S. Nuclear Regulctory Commission Atomic Scfety cnd Licensing Eccrd Washington, DC 20555 U.S.

Nuclear Regulatory Commission Ucshington, DC 20555 Edward O'Neill Ann P. Hodgdon, Esq.

_ Peter _Arth, Jr.

Office of the Genercl Ccunsel Truman Burns U.S.

Nuclect Regulatory Commission Robert Kinosion Ucshington, DC 20555 Peter G. Fcirchild, Esq.

Cclifornic Public Utilities Commission Joseph B.

Knotts, Jr.,

Esq.*

505 Ucn Ness Avenue Winsten & Strewn San Francisco, CA 99102 1400 L Street, N.W.

Ucshington, DC 20005 l

Adjudicatory File Secretcry of the Commission l

U.S. Nuclear Regulatory Commissicn Docketing cnd Service Brcnch Wcshington, DC 20555 U.S.

Nuclect Regulctory Ccmmission Ucshington, DC 20555 Robert R. Wellington, Esq.

Dicblo Canycr. Independent Safety Committee 857 Ccss Street, Suite D Monterey, CA S3940 Christcpher Warner, Esq.*

Richcrd Locke, Esq.

Pccific Gcs and Electric Co.

77 Becle Street San Francisco, CA 94105 Jill ZamEk Dated May 21, 1993, Son Luis Obispo County, CA I

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