ML20113A809

Submits Addl Info Re Thermo-Lag Fire Barriers,Per GL 92-08

ML20113A809
Person / Time
Site:	Wolf Creek
Issue date:	06/20/1996
From:	Muench R WOLF CREEK NUCLEAR OPERATING CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
ET-96-0039, ET-96-39, GL-92-08, GL-92-8, NUDOCS 9606250350
Download: ML20113A809 (5)

Text

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4 W$LF CREEK NUCLEAR OPERATING CORPORATION Richard A. Muench Vice President Engineering June 20, 1996 ET 96-0039 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Station F1-137 Washington, D. C. 20555

Reference:

1) Letter ET 95-0061 dated June 27, 1995, from R. C.

Hagan, WCNOC, to the USNRC

2) Letter ET 95-0004 dated February 15, 1995, from N. S. Carns, WCNOC, to the USNRC

3) Letter ET 95-0013 dated March 10, 1995, from F. T. Rhodes, WCNOC. to the USNRC

4) NRC Letter dated May 21, 1996, " Request for Additional Information, Thermo-Lag Related Ampacity Derating Issues, Wolf Creek Generating Station"

Subject:

Docket No. 50-482: Additional Information Regarding Thermo-Lag Fire Barriers Gentlemen:

In Reference 1 Wolf Creek Nuclear Operating Corporation (WCNOC) stated that we were continuing with the resolution of the Thermo-Lag issues at the Wolf Creek Generating Station (WCGS) in accordance with the schedule provided in Reference 2, and that we would provide a revised schedule should additional examinations or testing be required or if certain issues, such as ampacity derating, were not resolved in time to support our schedule. Reference 4 requested additional information be provided within 60 days from receipt of Reference 4, to address several questions and apparent errors with the ampacity derating calculations submitted by Wolf Creek Nuclear Operating Corporation (WCNOC) by Reference 3. Due to the nature of the information requested additional evaluation and review of WCGS's ampacity derating Thermo-Lag issue will be required. This work will be completed by August 30, 1996.

This is described in greater detail below.

In addition to the above, WCNOC discussed recent changes in our approach to resolving the WCGS Thermo-Lag installation issues in a May 28, 1996, telecon with Ms. Daniele Oudinot, NRC Plant Systems Branch, and Mr. Jim Stone, Wolf Creek NRC Project Manager. In that telecon WCNOC explained that, due to information received from recent industry meetings and discussions with Union Electric and other Licensees, WCNOC has decided to replace our Thermo-Lag material installed to meet 10CFR50, Appendix R, requirements with an alternate material, instead of trying to justify the continued use of the Thermo-Lag material. As a result, additional evaluations and plant modifications will be 1 required. 9606250350 960620 PDR ADOCK 05000482 o r AU(>T rd b> F PDR g PO Bru 411 i Banington. KS tF&9 Phone (316) 364 8831 j -

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l ET 96-0039 l Page 2 of 4  !

l WCNOC stated that this additional work will be completed on or before December 31, 1996, and that we would submit a letter in mid-June that would provide a summary of our plans to resolve the Thermo-Lag issue at WCGS, state the revised schedule date for the completion of the resolution, and address the additional information requested by Reference 4. This information is provided below.

RESOLUTION OF THERMO-LAG INSTALLATION ISSUES In previous submittals WCNOC has discussed the completion of all activities associated with the WCGS plant-specific Thermo-Lag applications that were considered outside of the scope of the NEI testing program. In these submittals WCNOC also described our participation in the NEI testing program in order to address our remaining Thermo-Lag applications. Specific interest was with the NEI Phase III tests of post-buttered joint configurations because WCNOC applications utilized post-buttered joint construction. NEI Phase III ,

testing was conducted in December of 1995 and the final revisions of the NEI Application Guide, reflecting the Phase III test results, was issued in February of 1996.

In Reference 2 WCNOC committed to completing all WCGS Thermo-Lag resolution action items by June 30, 1996. This date was based on the NEI industry test  !

program schedule as of February of 1994. WCNOC has completed an evaluation of )

all the remaining WCGS Thermal-Lag applications using the NEI Application l Guidelines. Based on the results of that evaluation, WCNOC has decided to )

install alternate fire barrier material and not rely on Thermo-Lag for protection of electrical raceway. WCNOC is working jointly with Union Electric to develop a joint resolution strategy. Earlier (than Reference 2) submittals discussed several possible resolution methods that WCNOC intended to evaluate for applicability to WCGS. Of those methods, WCNOC has decided to perform one of the following for Thermo-Lag conduit and raceway applications installed to satisfy commitments to 10 CFR 50, Appendix R:

1. An analysis to document that the fire barrier wrap on the raceway is not required to achieve safe shutdown,

2. Modifications to the plant such that the fire wrap on the raceways would no longer be required for safe shutdown,

3. Modifications to reroute wrapped conduits and raceways, or 1

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4. Replace existing Thermo-Lag 330-1 with Darmatt KM-1. This includes the y

radiant energy heat shield used inside containment. )

l The above actions will be completed on or before December 31, 1996. After the above actions are complete, Thermo-Lag will no longer be relied on to satisfy WCNOC commitments to 10 CFR 50, Appendix R, for electrical raceway. As a result, the Thermo-Lag " material" and " barrier parameter" issues originally 4 described in the December 22, 1993 Request for Additional Information I addressed to Mr. Neil S. Carns, WCNOC, from Mr. L. J. Callan, USNRC, will no longer be applicable.

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ET 96-0039 =

Page 3 of 4 With respect to Thermo-Lag installed to achieve physical independence between electrical systems associated with the Class 1E power system, WCNOC will document, by December 31, 1996, that -the existing Thermo-Lag IEEE 384-74 installations satisfy the requirements of IEEE 384-74. ,

i CHEMICAL CONSISTENCY OF INSTALLED THERMO-LAG ,

In Reference 1, we indicated that results of Pyrolysis Gas Chromatography l testing for organic materials on WCNOC samples submitted for testing indicated [

that the WCNOC samples are consistent, in terms of chemical composition, to the baseline results tested by NEI. Reference 1 also stated that NEI would be conducting inorganic testing on several more WCNOC samples, that testing would be completed in July, 1995, and the results sent to the NRC. Based ca the results of the NEI testing, and the NRC letter to NEI dated October 20, 1995, WCNOC considers the chemical consistency issue with Thermo-Lag resolved.

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AMPACITY DERATING ISSUE Regarding the infMmation on ampacity derating requested by Reference 4, WCNOC has reviewed *.ne WGS ampacity derating calculations in light of the questions and comments received . in Reference 4. WCNOC agrees with the comment in Reference 4 that the current WCGS calculations should not be used, and is- l

, currently reviewing the Texas Utilities (TU) and Tennessee Valley Authority.

(TVA) data, as suggested in Reference 4, in order to revise our. calculations.

Based on preliminary review, we . believe the TU and TVA data envelope our ampacity margin data. As indicated above, most of the Thermo-Iag installed at WCGS will be removed and replaced with Darmatt KM-1. Therefore, the Thermo-Lag ampacity derating factors will apply only to IEEE 3E_-74 installations, and for any Thermo-Lag that will be abandoned in place. WCNOC will have the ampacity derating issue resolved by August 30, 1996.

WCNOC will utilize vendor-supplied ampacity derating factors for any Darmatt KM-1 material installed to replace Thermo-Lag. Cable ampacity margins for Darmatt installations will be assessed as part of the Thermo-Lag resolution project that will be fully completed on or before December 31, 1996.

COMBUSTIBILITY ISSUES

, Thermo-Lag that will be left installed in the plant will be ovaluated and

! added to the combustible loading for the applicable fire areas, using

{ industry-developed heat release values for the material. The plant Fire l l Hazards Analysis will be updated with the new combustible loading values.

3 This activity will be completed as part of the Thermo-Lag resolution project j that will be fully completed on or before December 31, 1996, i

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ET 96-0039 i Page 4 of 4 1

l As indicated in previous correspondence concerning Thermo-Lag, WCNOC will submit a final response to Generic Letter 92-08 notifying the NRC when all corrective actions to resolve the Thermo-Lag issues are complete. Based on the current schedule, WCNOC will submit this letter on or before January 31, 1997.

If you have any questions concerning the above issues, please contact me at (316) 364-8831, extension 4034, or Mr. Terry S. Morrill at extension 8707.

Very truly yours, I

l' Richar A. Muench RAM /jra cc: L. J. Callan (NRC)

W. D. Johnson (NRC)

J. F. Ringwald (NRC)

J. C. Stone (NRC)

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STATE OF KANSAS )

) SS CotRrrY OF COFFEY )

Richard A. Muench, of lawful age, being first duly sworn upon. oath says that l: he'is Vice President Engineering of Wolf Creek Nuclear Operating Corporation;

that he has read the foregoing document and knows the content thereof; that he has executed that same for and on behalf of said Corporation with full power and authority to do so; and that the facts therein stated are true and correct to the best of his knowledge, information and belief.

By l Richard'A. Muench~

Vice President Engineering i

SUBSCRIBED and-sworn to before me this 2.Cf4 day of $we, , 1996.

zn/', JE . U ed

! ANGELA E.WESSEL NtadPubpc Notary Public State of Kansas

<Wy Appt. Exp6res 4 7/0.3/97 Expiration Date u to, J, / 999

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