ML20045D228
| ML20045D228 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 06/09/1993 |
| From: | Repka D PACIFIC GAS & ELECTRIC CO., WINSTON & STRAWN |
| To: | Bechhoefer C, Kline J, Shon F Atomic Safety and Licensing Board Panel |
| References | |
| CON-#293-14037 OLA-2, NUDOCS 9306280110 | |
| Download: ML20045D228 (9) | |
Text
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2'Pr N9 2%O (202) 371-5726 June 9, 1993 Charles Bechhoefer, Chairman Frederick J.
Shon Administrative Judge Administrative Judge Atomic Safety and Licensing Atomic Safety and Licensing Board Board U.S.
Nuclear Regulatory U.S.
Nuclear Regulatory Commission Commission Washington, DC 20555 Washington, DC 20555 Jerry R.
Kline Administrative Judge Atomic Safety and Licensing Board U.S. Nuclear Regulatory Commission Washington, DC 20555 Re:
Pacific Gas and Electric Co. (Diablo Canyon Nuclear Power Plant, Units 1 and 2), Docket Nos. 50-275-OLA. 50-323-OLAs(Construction Period Recaoture)
Dear Administrative Judges:
In reviewing the transcript of the Prehearing Conference held on May 11-12,
- 1993, we were reminded that there was a discussion of PG&E's response to Generic Letter 92-08 regarding Thermo-Lag fire barriers (Tr. 449-451).
The response is dated April 16, 1993.
To complete the record, a copy is attached.
The parties to this proceeding should already have copies through the normal distribution for Diablo Canyon correspondence.
Very truly yours, k\\
k David A. Repka Counsel for Pacific Gas &
Electric Company Enclosure cc:
Service List (w/o attachment) 9306280110 930609 q
PDR ADDCK 05000275 3'
0 O
' Pacific Gas and ilostric Company 77 Bea'e street. Room 1451
. Gregory M. Rueger 4
PD. Box 770000 Senior Vice President and.
San Francisco. CA 94177 General Manager 415/973-4684 fJuclear Power Generation i'
Fax 415/973 2313 April 16, 1993 PG&E Letter No. DCL-93-090 7y U.S. Nuclear Regulatory Commission 2.-
t ATTN:
Document Control Desk 9
Washington, D.C.
20555
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Re:
Docket No. 50-275, OL-DPR-80 Docket No. 50-323, OL-DPR-82 Diablo Canyon Units 1 and 2 Response to NRC Generic Letter 92-08 Gentlemen:
PG&E's response to NRC Generic Letter (GL) 92-08, "Thermo-Lag 330-1 Fire Barriers," dated December 17,.1992, is provided in the Enclosure.
PG&E is continuing to follow NUMARC's industry-sponsored efforts for testing of Thermo-Lag 330-1 and is awaiting final NRC-guidance on fire test acceptance criteria.
This information will-be reviewed for applicability to DCPP when it becomes available. Any upgrade or replacement of existing Thermo-Lag configurations based on the results of this work will be implemented by PG&E as appropriate.
_(.
Sincerely, SW f
Gregory M. Rueger cc:
Ann P. Hodgdon John B. Martin
-Mary H. Miller Sheri R. Peterson CPUC Diablo Distribution Enclosure 6073S/85K/ALN/2232 G
RECEIVED JUN08 1993 CHRISTOPHER J. WARNER
PG&E Letter No. DCL-93-090
~
i ENCLOSURE RESPONSE TO NRC GENERIC LETTER 92-08 The reporting requirements of Generic Letter (GL) 92-08, "Thermo-Lag 330-1 Fire Barriers," and PG&E's responses follow.
1.
" State whether Thermo-Lag 330-1 barriers are relied upon (a) to meet 10 CFR 50.48, to achieve physical independence of electrical systems, (b) to meet a condition of a plant's operating license, or (c) to satisfy a licensing commitment.
If applicable, state that Thermo-Lag 330-1 is not used at the facility. This generic letter applies to all 1-hour and all 3-hour Thermo-Lag 330-1 materials and barrier systems assembled by any assembly method such as by assembling preformed panels and conduit shapes, as well as spray, trowel and brush-on applications."
PG&E Response PG&E uses Thermo-Lag in a total of fourteen fire areas in Units 1 and 2 of the Diablo Canyon Power Plant (DCPP), but credits Thermo-Lag applications as a fire barrier in only 11 of these areas to protect safe shutdown functions as required by 10 CFR 50, Appendix R, Section III.G.
Information regarding the eleven fire areas at DCPP for which Thermo-Lag (J
330-1 is credited as a fire barrier was previously transmitted to the NRC in response to Supplement 1 of NRC Bulletin 92-01. Table 1 provides a list of all fire areas where Thermo-Lag is installed at Diablo Canyon.
This list is similar to that submitted in PG&E's response to Supplement 1 of Bulletin 92-01, but has been updated to include the Thermo-Lag installations that are not credited as fire barriers.
Two locations where Thermo-Lag is not credited as a 1 or 3-hour fire barrier are in the Units 1 and 2 containments (Fire Areas 1 and 9, respectively). The Thermo-Lag installations inside the containment buildings are considered radiant energy heat shields as discussed in SSERs 23 and 31 and PG&E's response to Supplement 1 of Bulletin 92-01.
There also are several Thermo-Lag installations that had originally been credited as fire barriers; however, a reverification of the Appendix R safe shutdown analysis in support of PG&E's Appendix R design basis reconstitution effort demonstrated that these Thermo-Lag applications were no longer required as fire barriers to achieve safe shutdown separation.
nr 6073S/85X -
For the Thermo-Lag applications at DCPP which are credited as fire I
barriers:
l a)
Thermo-Lag was installed and is relied upon at Diablo Canyon to meet 10 CFR 50.48 requirements for safe shutdown separation, but not to achieve physical independence of electrical systems.
PG&E achieves physical independence of electrical systems at Diablo Canyon by compliance with Institute of Electrical and Electronics Engineers (IEEE) 279-1971 and 308-1971, which do not rely upon the use of Thermo-Lag, j
b)
Thermo-Lag 330-1 is not relied upon to meet a condition of the Diablo Canyon operating licenses.
c)
PG&E has no specific commitments to install Thermo-Lag 330-1 at DCPP. As part of PG&E's compliance with Appendix R, PG&E committed to provide 1 or 3-hour fire barriers to protect Appendix R safe shutdown circuits, as documented in SSERs 23 and i
31.
PG&E installed Thermo-Lag in several areas to satisfy the I and 3-hour fire barrier commitments.
2.
"If Thermo-Lag 330-1 barriers are used at the facility, (a)
State whether or not the Ifcensee has qualified the Thermo-Lag
\\
330-1 fire barriers by conducting fire endurance tests in accordance with the NRC's requirements and guidance or licensing commitments.
[
(b)
State (1) whether or not the fire barrier configurations installed in the plant represent the material, workmanship, methods of assembly, dimensions, and configurations of the qualification test assembly configurations; and (2) whether or not the ifcensee has evaluated any deviations from the tested configurations.
(c)
State (1) whether or not the as-built Thermo-Lag 330-1 barrier configurations are consistent with the barrier configurations used during the ampacity derating tests relied upon by the licensee for the ampacity derating factors used for all raceways protected by Thermo-Lag 330-1 (for fire protection of safe shutdown capability or to achieve physical independence of electrical systems) and (2) whether or not the ampacity derating test results relied upon by the ifcensee are correct and applicable to the plant design."
PG&E Response a)
PG&E has not conducted any specific fire endurance tests of Thermo-Lag materials.
PG&E relied on TSI-supplied installation details to qualify DCPP's installations.
However, as a result of recent industry testing of Thermo-Lag and reevaluation of test acceptance criteria for the fire barriers, PG&E now considers the TSI test results to be indeterminate.
b..
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o (b)(1)
The Thermo-Lag 330-1 fire barrier systems at DCPP were installed in accordance with TSI's published installation i
procedures.
Construction materials were obtained from TSI, and installation was performed by PG&E personnel who were trained by TSI and followed TSI procedures.
The Thermo-Lag installation details contained in DCPP's installation procedures were extracted from the TSI Technical manual.
i The procedures used and the quality control programs in place provide assurance that the Thermo-Lag configurations installed at DCPP represent the materials, workmanship, methods of assembly, dimensions, and configurations of TSI Technical Note 20684.
(b)(2)
Several deviations from TSI's Technical Note 20684 have been identified and evaluated by PG&E.
In 1991, deviations from the Technical Note were identified in Thermo-Lag enclosures built to provide separation for several diesel generator i
emergency stop and CO, switches; these enclosures were i
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subsequently replaced with Pyrocrete-enclosures.
Also, existing Thermo-Lag applications that consist of a j
combination of Pyrocrete and Thermo-Lag (see Table 1, Fire l
Areas 10 and 20), which represent a deviation from the configurations in the Technical Note, were evaluated in accordance with the guidelines outlined under NRC Generic Letter 86-10 and found to be acceptable. However, as a result of the recent industry testing of Thermo-Lag and j
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reevaluation of test acceptance criteria, PG&E now considers these conclusions to be indeterminate.
(c)(1)
PG&E is in the process of reviewing cable ampacity derating (c)(2) based upon the TSI-supplied ampacity derating factors for all raceways protected by Thermo-Lag 330-1 to satisfy Appendix R separation requirements..As discussed in PG&E's response to (b)(1), the Thermo-Lag installation details contained in DCPP's installation procedures were extracted from the TSI Technical m:nual.
The TSI-supplied ampacity-deratin'g factors were the basis-for the Thermo-Lag installations. and were. commensurate with 3
the knowledge and guidance of the industry at the time of installation. However, in light of the recent industry testing of Thermo-Lag that indicates these factors may not be correct, PG&E has performed a preliminary review of the ampacity derating factors provided by TSI, as well as those j
derating factors which were obtained from recent TV Electric tests, for both 1 and 3-hour Thermo-Lag configurations at
'DCPP. Based on this preliminary review, PG&E has determined that sufficient margin for ampacity derating exists for all raceways enclosed in Thermo-Lag barriers. These margins will be reviewed and confirmed with respect to the results of ampacity testing obtained from the NUMARC test program to k.
ensure adequacy of the existing margins.
6073S/85K o
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3.
"With respect to any answer to items 2(a), 2(b), or 2(c) above in the negative, (a) describe all corrective actions needed and include a schedule by which such actions shall be completed and (b) describe all compensatory measures taken in accordance with the technical specifications or administrative controls. When corrective actions have been completed, conff rm in writing their completion."
PG&E Response a)
A corrective action plan and schedule for addressing the indeterminate fire tests, configuration deviations, and ampacity issues at DCPP is included as Attachment 1.
As previously stated, PG&E intends to carefully review information that becomes available through the NRC, NUMARC, and the industry, and assess all viable options for each Thermo-Lag installation before determining a course of action.
Schedule dates for the NUMARC testing efforts will be communicated to NRC by NUMARC.
b)
The compensatory actions that were implemented at DCPP in regards to the Thermo-Lag issues are those described in PG&E's response to Supplement 1 to NRC Bulletin 92-01, and consist of a combination of hourly and continuous fire watches and portable fire detection systems. The specific actions for each Fire Area containing Thermo-Lag are described in PG&E's response to the Supplement and reiterated in Table 1.
4.
" List all Thermo-Lag 330-1 barriers for which answers to item 2 cannot g
be provided in the response due within 120 days from the date of this generic letter, and include a schedule by which such answers shall be provided."
PG&E Response Table 1 provides a list of all Thermo-Lag applications at DCPP. Because all Thermo-Lag applications have been identified, this question is not applicable.
Q:
6073S/85X _
Thermo-Lag Inste11ations Thermo-Lag Compensatory Fire Area (FA)
Installation Actions 1.
FA 3-BB One 3* o condult; box made from pre-Houriy Fire Watch (Unit 1 Containment Penetration formed panels for one 1* o conduit; boxes made from pre-formed panels for Area) 4 l unction boxes and 3 puil boxes 2.
FA 3-CC Two 3* o conduits; boxes made from Hourly Fire Watch (Unit 2 Containment Penetration pre-formed panels for 5 junction boxes Area) and 4 pull boxes 3.
FA 3-L One 4* o condult; box made from pre-Continuous Fire Watch, or Houdy Fire (85 Foot Elevation Auxiliary formed panels for 1 junction box Watch with Temporary 8-hour Ughts to ensure a lighted patch in case of Building)
Thermo-Lag failure causing loss of vital lights 4.
FA 4-B Two 4* o conduits Hourly Fire Watch (Access Control) 5.
FA 5-A-4 One 2* o conduit Hourly Fire Watch (Unit 1480 V Switchgear Room) 6.
FA5B4 One 2* o conduit Houdy Fire Watch (Unit 2 480 V Switchgear Room) 7.
FA 22-0 (Unit 2 Diesel Generator Two 2* O conduite Continuous Fire Watch, or Portable Detection System with Hourfy Fire Corridor)
I :.
Watch 8.
FA 30-A-5 One box made from pre-formed panels Hourly Fire Watch (Units 1 and 2 Intake Structure) for grouped condults (one 1* o, one 1.5*
o, two 2* 9, and two 3* 0) for each unit; one box made from pre-formed panels for 1 junction box for each unit 9.
FA 10 Thermo-Lag /Pyrocrete Barrier Hourfy Fire Watch (Unit 1 - 12 kV Switchgear Room)
- 10. FA 20 Thermo-Lag /Pyrocrete Barrier Houriy Fire Watch (Unit 2 - 12 kV Switchgear Room)
- 11. FA 13-E/11-B 2 Partial Wall constructed of pre-formed Continuous Fire Watch, or Portable (107 Foot Elevation Turbine Thermo-Lag panels Detection System with Houriy Fire Watch Building)
- 12. FA 1 (Unit 1 Containment)
One 1.5 o conduit; 5 junction boxes N/A (radiant energy heat shield)
- 13. FA 9 (Unit 2 Containment) 2 - 1.5* o conduit; 5 junction boxes N/A (radiant energy heat shield) b 14. FA 19-A (Unit 2 85 Foot 2
2* O condult; 2 junction boxes N/A i
(,
Elevation Turbine Building)
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6073S/85K
PG&E 1.etter No. DCI.-93-090' Corrective Action Plan and Schedule 9
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