ML20210T056

Forwards Request for Addl Info Re 970320 Response to GL 92-08, Thermo-Lag 330-1 Fire Barriers, for Donald C Cook Nuclear Power Plant,Units 1 & 2

ML20210T056
Person / Time
Site:	Cook
Issue date:	08/25/1997
From:	John Hickman NRC (Affiliation Not Assigned)
To:	Fitzpatrick E INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
Shared Package
ML17333B030	List: ML20210T056
References
GL-92-08, GL-92-8, TAC-M85538, TAC-M85539, NUDOCS 9709120270
Download: ML20210T056 (7)

Text

_ _ _ _ _ . ..

August 25, 1997 1

I Mr. E. E. Fitzpatrick, Vice President indiana Michigan Power Company l

Nuclear Generation Group 500 Circle Drive Buchanan, MI 49107

SUBJECT:

DONALD C. COOK NUCLEAR PLANT, UNIT NOS.1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION RE: THERMO-LAG RELATED AMPACITY DERATING ISSUES (TAC NOS M85538 AND M85539)

Dear Mr. Fitzpatrick:

By letter dated March 20,1997, Indiana Michigan Power Company submitted a response to the NRC Request for Additional Information related to Generic Letter 02-08, "Thermo-Lag 330-1 Fire Barriers," for the Donald C. Cook Nuclear Power Plant, Unit Nos.1 and 2. The NRC staff, in conjunction with its contractor, Sandia National Laboratories, has completed the review of your response and has identified a number of open issuet, and concems requiring clarification. Please respond to the enclosed Request for AdditionalInformation within 45 days.

f Please contact me at (301) 415-3017 if you have any questions on the above.

Sincerely, Original Signed By jg John B. Hickman, Project Manager Project Directorate 1113 Division of Reactor Projects Ill/IV Office of Nuclear Reactor Regulation Docket Nos. 50-315 and 50-316

Enclosure:

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-***/ August 25, 1997 Mr. E. E. Fitzpatrick, Vice President Indiana Michigan Power Company Nuclear Generation Group 500 Circle Drive Buchanan, MI 49107

SUBJECT:

DONALD C. COOK NUCLEAR PLANT, UNIT NOS.1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION RE: THERMO-LAG RELATED AMPACITY DERATING ISSUES (TAC NOS. M85538 AND M85539)

Dear Mr. Fitzpatrick-By letter dated March 20,1997, Indiana Michigan Power Company submitted a response to the NRC Request for Additional information related to Generic Letter 92-08, "Thermo-Lag 330-1 Fire Barriers," for the Donald C. Cook Nuclear Power Plant, Unit Nos.1 and 2. The NRC staff, in conjunction with its contractor, Sandia National Laboratories, has completed the review of your response and has identified a number of open issues and concems requiring clarification. Please respond to the enclosed Request for AdditionalInformation within 45 days.

Please contact me at (301) 415-3017 if you have any questions on the above.

Sincerely, John B. Hickman, Project Manager Project Directorate 111-3 Division of Reactor Projects lil/IV Office of Nuclear Reactor Regulation Docket Nos. 50-315 and 50-316

Enclosure:

Request for AdditionalInformation cc w/ encl; See next page l

t

- E. E..Fitzpatrick Donald C. Cook Nuclear Plant Indiana Michigan Power Company Unit Nos. I and 2 cc:

Regional Administrator, Region III Steve J. Brewer U.S. Nuclear Regulatory Commission Indiana Michigan Power Company 801 Warrenville Road Nuclear Generation Group Lisle, IL 60532-4351 500 Circle Drive Buchanan, MI 49107 Attorney General i Department of Attorney General 525 West Ottawa Street Lansing, MI 48913 Township Supervisor Lake Township Hall P.O. Box 818 Bridgman, MI 49106 Al Blind, Site Vice President Donald C. Cook Nuclear Plant 1 Cook Place t Bridgman, MI 49106 U.S. Nuclear Regulatory Commission Resident Inspector's Office-7700 Red Arrow Highway Stevensville, MI 49127 Gerald Charnoff, Esquire Shaw, Pittman, Potts and Trowbridge 2300 N Street, NW.

Washington, DC 20037 Mayor, City of Bridgman P.O. Box 366

^

- Bridgman, MI 49106 Special Assistant to the Governor Room 1 - State Capitol Lansing, MI 48909 4 Drinking Water and Radiological Protection Division Michigan Department of Environmental Quality 3423 N. Martin Luther King Jr Blvd P.O. Box 30630 CPH Mailroom Lansing, MI 48909-8130 1

4 4

.: REQUEST FOR ADDITIONAL INFORMATION DONALD C. COOK NUCLEAR POWER PLANT. UNIT NOS.1 AND 2 FIRE BARRIER AMPACITY DERATING ISSUES fTAC NOS, M85538 AND M85539) i 1.0 - BACKGROUND .

l 1 By letter dated March 20,1997, Indiana Michigan Power Company (the licensee) submitted its response to the second NRC Request for Additional Information (RAl) related to Generic Letter 92-08, "Thermo-Lag 330-1 Fire Barriers, for the Donald C. Cook Nuclear Power Plant (DCNPP), Unit Nos.1 and 2. This response included the following attachments:

Attachment 1: Response to RAI Regarding Thermo-Lag Related Ampacity Derating issues

for Cook Nuclear Plant; .

Attachment 2: Table Depicting Correlation Between the Predicted and Measured Ampacities; i Attachment 3: Model Computer Code; i

Attachment 4: Test Report CL-492; i

Attachment 5: Comparison Tables Providing Base Information Regarding Trays and Conduits Cable Full Load Amperes, and Comparison of Calculated

{ Ampacities vs. ICEA Ampacities; and Attachment 6: Ampacity vs. Depth of Fill Plot for #12 AWG Cable in Tray.

The DCNPP ampacity derating methodology involves the application of two separate but

related models, in the first model (denoted as Part 1 Analysis), the licensee calculates the overall heat rejection capacity for a given cable tray (conduit) based on heat transfer correlations and calculations, in this analysis, a series of calculations are performed for each uniquely sized cable in the tray and the limiting heat intensity is used _in the Part 2 analysis for all cables in the tray, in the second model (denoted as Part 2 Analysis), the licensee calculates, based on the Part 1 analysis, the allowable ampacity limit for individual cables.

This calculation is basically a partitioning of the total heat load to individual cables.

The NRC staff, in conjunction with its contractor, Sandia National Laboratories (SNL), has

- completed the review of the licensee's submittal, and requires that the questions listed below are addressed by the licensee.

' 2.0 QUESTIONS -

2.1 The staff requested in its RAI dated December 2,1996, (Item 2.2 - Part 1 Analysis,

! Appendix A of Attachment A) that Appendix C, as well as any other documentation that will support the validation of the experiments cited in the licensee submittal dated May 12,1995, be submitted for staff review.

[

! ENCLOSURE l-l r

Although the licensee submittal dated March 20,1997, provided additional clarification, SNL found that the licensee plot of ampacity versus (d/R,)" and its initial validations were based only on those tests that involved a nondiverse cable fill. The original concem raised by SNL pertained to the fact that the licensee has not shown that the thermal model, specifically, the diameter based partitioning method, was appropriate for diverse cable loads actually installed in the plant. An analysis of the licensee test data by SNL indicates that the licensee assumed the diameter ,

partitioning method may not be appropriate and may result in overestimation of the amrwity limits for smaller cables in diversely loaded trays (see Section 3.2 and Appendix C of the attached SNL report for furiher details.) The licensee is requested to address the subject concems and to provide an adequate validation of the heat load partitioning methodology.

2.2 The staff requested in its RAI dated December 2,1996, (Item 2.3 - Part 2 Analysis, Appendix B of Attachment) that the licensee provide a direct comparison of predicted cable ampacity limits to those measured in experiments on the corresponding system in order to validate its calculations.

SNL finds that the response provided in the licensee submittal dated March 20,1997,

[

to be only partially responsive to the subject concems. Specifically, model versus experimental comparisons have only been provided for two specific tests. None of the cables involved with the subject tests were loaded to its ampacity limit. SNL identified the following concems with the licensee validations efforts: (1) the licensee model predicts an ampacity value significantly higher than measured in the test; (2) the licensee studies did not consider the full range of test dates available to the licensee; and (3) SNL assessments have identified potential inconsistencies between the model results and experimental test data. Overall, SNL finds that the licensee validations study, as provided by the subject licensee submittel, to be inadequate to justify reliance on the licensee approach to thermal modeling techniques (see Appendix C, Section 2.2, and Section 3.3.2 of the attached SNL report for further details.)

The licensee is requested to address the subject concems and to provide a complete validation of ampacity model results to applicable experimental test data.

2.3 The staff requested in its RAI dated December 2,1996, (Item 2.3 - Part 2 Analysis, Appendix B of Attachment) that the licensee provide the supporting validation results which justified its treatment of cable trays using equivalent annular region assumptions.

As stated in item 2.2 above, SNL has found that the licensee validation studies to be

. inadequate and that, in its own validation studies, SNL identified inconsistencies and potential nonconservatisms in the licensee thermal model. (See Sections 3.3.6 and 4.2, and Appendices B and C of the attached SNL report for further details.)

The licensee is requested to address the subject concems regarding validation of its thermal model.

1 .

'4 2.4 The staff requested in its RAI dated December 2,1996, (ltem 2.4 - Representative Calculation Results) that the licensee provide a direct comparison between ampacity loads installed at DCNPP to the ICEA Standard P-54 440 ampacity limits and to justify.

any cases which exceed ICEA P-54-440 limits. SNL reviewed Attachment 5 calculations which were contained in the licensee submittal dated March 20,1997, and identified four apparent errors. As a result of a reanalysis of the most significant -

of the licensee cable applications, SNL identifed four specific cables which appear to be nominally overloaded even in the absence of the fire barrier _ system and six additional cables which may have insufficient ampacity dorating margin. (See Section 4.5 and Appendix A of the attached SNL report for further details.)

The licensee is requested to provide additional justification for the acceptability of the ampacity loading on the 10 cables as identifed in the attached SNL report.

2.5 SNL found that several licensee responses as provided in the licensee submittal dated  !

March 20,1997, did not provide sufficient information to resolve the identifed  ;

concems cited in the staff RAI dated December 2,1996. However, all of the deficient responses were directly related to thermal modeling concems. Those deficient responses which were not identified in the above items are discussed in Sections  !

3.3.3, 3.3.6, 3.3,7, 3.3.8, 3.3.9, 3.4.1, 3.4.2, 3.4.6L and 3.4.8 of the attached SNL report Although the staff agrees with its contractor SNL that the pursuit of an integrated resolution of the concems for the licensee thermal model and its implementation is the primary review objective, the staff requests that the licensee ^

j address the above deficient responses in those instances where the applicable concem may materially impact the acceptability of the licensee ampacity model results and validation studies.

Overall, SNL has recommended that the licensee thermal model should not be credited as an appropriate basis for analysis without significant further review and 1 validation. Further, in the case where the licensee plans to continue to seek-acceptability of its current thermal model, SNL recommends that the licensee provide the following changes or additional information:

• The actual computer code implementation should be reformulated in order to  !

comply with accepted engineering practice for a structured program. -This  !

I revision should include an organized logical code structure that allows for a direct and clear understanding of the program flow and flow control, and the explicit ,

definition of intemal variables, input variables, and flow control parameters. The - l revised code should be amenable to independent implementation and verification.

i

• The validation study should be supplemented to provide a direct comparison of .I I

total allowable heat rejection capacity as calculated by the thermal model and as measured in these tests, i.e., the 11 specific tests cited in the licensee CL-492 test report.-- The subject tests include those tests performed using the " solid i' bottom / solid cover /no fire barrief tray configuration and those tests performed using the " vented bottom /no cover / solid fire barrief tray configuration.

4 The staff fully supports the above SNL recommendations. The staff requests that the licensee either implement those recommendations or provide an attemate technical analysis to resolve the subject concems regarding the licenses thermal model and its implementation at the Donald C. Cook Nuclear Plant.

Attachment:

Ltr Rpt to USNRC, Rev. O, dtd 6/19/97 4

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