ML20216C323
| ML20216C323 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 12/20/1996 |
| From: | Nowlen S SANDIA NATIONAL LABORATORIES |
| To: | Ronaldo Jenkins NRC (Affiliation Not Assigned) |
| Shared Package | |
| ML20216C234 | List: |
| References | |
| CON-FIN-J-2017 NUDOCS 9804140390 | |
| Download: ML20216C323 (12) | |
Text
1s A Technical Evaluatirn of the Wcif Creek Nuclear Operating Corporation Analysis of Fire Barrier Ampacity Derating Factors l
l l
l l
l ALetterReport to the USNRC l
l l
l Revision 0 i
l l
D - - M 20,1996 q
l 1
l
)
Pgd h Steve Nowlen SandiaNational Laboratories l
Albuquerque,New Mexico 87185-0737 l
(505)S45-9850 l
l l
l.
Prepared for:
Ronaldo Jenkins Electrical Engineering Licensing Branch Office ofNuclear Reactor Regulation U. S. Nuclear Regulatory Comndssion Washington,DC 20555 USNRC JCN J-2017, Task Order 7 ATTACHMENT 2 9804140390 980406 f
PDR ADOCK 05000482 P
PDR r
..6.
TABLE OF CONTENTS:
Sostion P. ass r
FORWARD......................................................... iv
1.0 INTRODUCTION
................................................ I 1.1 Objective................................................... I 1.2 Overview of the Utility Ampacity Derating Approach.................. I 1.3 Organization of Report........................................ 2 i
2.0 AN ASSESSMENT OF THE UTILITY RAI RESPONSES................ 3 2.1 RAI Item 1: Calculation Errors.................................. 3 2.1.1 Brief Statement of Concern............................... 3 2.1.2 Summary of Utility Response............................. 3 l
2.1.3 Assessment ofResponse Adequacy......................... 3 l
2.2 RAI Item 2: Use ofindustry Data................................ 3 2.2.1 Bdef Statement of Concem............................... 3 2.2.2 Summary of Utility Response............................. 3 l
2.2.3 Assessment ofResponse Adequacy......................... 3 2.3 RAI ltem 3: Non-Continuous Loads Item 1........................ 3 2.3.1 Brief Statement of Concern............................... 3 2.3.2 Summary of Utility Response............................. 4 l
2.3.3 Assessment of Response Adequacy......................... 4 2.4 RAI Item 4: Triplex Versus Three-Conductor Ampacities............. 4 h
2.4.1 Brief Statement of Concern............................... 4 l
2.4.2 Summary of Utility Response............................
4, i
l 2.4.3 A====* ofResponse Adequacy......................... 4 L
2.5 RAI Item 5: Two-Conductor Conduit Ampar*aies......
............4 L
2.5.1 Brief Statement of Concern............................... 4 2.5.2 Summary of Utility Response............................. 4 2.5.3 Assessment ofResponse Adequacy......................... 5 i
2.6 RA11 tem 6: NEC Percentage Fill Limits........................... 5 2.6.1 Brief Statement of Concern............................... 5 2.6.2 Summary of Utility Response............................. 5 2.6.3 Assessment of Response Adequacy......................... 5 2.7 RAI Item 7: 80% of Open Air Tray Ampacity Limit.................. 5 2.7.1 Brief Statement of Concern............................... 5 2.7.2 Summary of Utility Response............................. 5 2.7.3 Assessment of Response Adequacy......................... 5 2.8 RAI Item 8: Non-Continuous I. mads Item 2........................ 5 2.8.1 Brief Statement of Concern............................... 5 1
2.8.2 ' Summary of Utility Response............................. 6 2.8.3 A*== ment of Response Adequacy......................... 6
..n
2.9 RAI Item 9: N:n-Continuous Loads Item 3........................ 6
~
2.9.1 Bdef Statement of Concern............................... 6 2.9.2 Summary of Utility Response............................. 6 2.9.3 Assessment ofResponte Adequacy......................... 6 2.10 RAI Item 10................................................ 6 2.10.1 Bdef Statemt.nt of Concem............................... 6
)
2.10.2 Summary of Utility Response............................. 6 l
2.10.3 Assessment of Response Adaquey......................... 7 2.11 RAI Item 11: Under-VoltaSe Conditions.......................... 7 2.11.1 Brief Statement of Concern............................... 7 2.11.2 Summary of Utility Response............................. 7 l
2.11.3 Assessment of Response Adequacy......................... 7 3.0 ~
SUMMARY
OF FINDINGS AND RECOMMENDATIONS............... 8 i
1 l
i r
s
FORWARD j
l The United States Nuclear Regulatory Commission (USNRC) has solicited the support of Sandia NatipnalJ aboratories (SNL) in the review of utility submittals associated with fire protection and electrical engineering. This letter report documents the results of a SNL review of the utility response to an USNRC RAI ofMay 11,1996 sent to the Wolf Creek Nuclear Operating Corp. (WCNOC). The RAI was related to utility submittals dealing l
with the issue of ampacity loads for cable trays and conduits protected by Thermo-Lag l
330-1 fire baniers. These documents were submitted by the utility in response to USNRC l
Generic Letter 92-08. This work was performed as Task Order 7 ofUSNRC JCN J2017.
l This report is the second and final report to be generated under this task order.
I I
l i
i 4
IV
1.0 INTRODUCTION
~
1.1 Objective In response to USNRC Generic Letter 92-08, the Wolf Creek Nuclear Operating Corp.
(WCNOC) provided documentation of the utility position regarding ampacity derating factors associated with its installed fire barrier systems. On April 19,1996 SNL provided the USNRC with a repon documenting the Simp of a review of these utility submittals.
As a result of this review, a number of technical concerns related to the manner in which the utility had analyzed its ampacity loads were identified. On May 21,1996 the USNRC sent a Request for Additional Information (RAI) to the utility requesting resolution of these technical concerns.
'Ibe objective of the current rev'sw was to assess the adequacy of the utility's response to this USNRC RAI. The utility response reviewed by SNL was provided in +.he form of two utility documents as follows:
- I.etter, June 20,1996 (item ET 96-0039), Richard A. Muench, WCNOC, to the USNRC Document ControlDesk.
-I.4tter, August 23,1996 Otem WM 96-0092), Neil S. Carns, WCNOC, to the USNRC Document Control Desk, with one attachment entitled " Response to the Request for AdditionalInformation Regarding Thermo-Lag-Related Ampacity Derating Issues."
SNL was requestd a review these response submittals under the tenns of the general technical suppon contract JCN J-2017, Task Order 7. This letter repon documents SNLs findings. The objective was to assess the adequacy of the utility responses to the USNRC RAI. In summary, SNL finds that all of the outstanding technical issues have been adequately resolved, and no funher actions are recommended.
l 1.2 Overview of the Utility Ampacity Derating Approach The original consideration of ampacity derating factors for fire barriers at WCNOC (which was reviewed Fy SNL in April 1996) was based on two complementary analytical methods. The review of these original utility analyses had revealed numerous significant errors and shoncomings. As a result, the USNRC RAI had recommended that the utility abandon these calculations, and instead rely on available industry test results. This advice has beer. followed by the utility in its response.
Hence, the utility assessments of ampacity load factors are now based on the use of test data either from Texas Utilities ('IU) or firom Tennessee Valley Authority (TVA). The ampacity derating values determined in these tests are simply compared to the available ampacity margin for specific cables. This is a much more simplistic approach than that the utility had originally attempted. Given the very large margins which are available at WCNOC, it is not surprising that the utility has been able to demonstrate that all of the analyzed cables are operating within acceptable ampacity limits.
1
1 ls~
\\
l 1.3 Organization cfRepon i
This review has focused on an assessment of the acceptability of the utility responses to the USNRC RAI items as set fonh in its memorandum ofMay 21,1996. Chapter two l
provides an item by hem assessment of the utility response to each of the RAI items.
Chapter 3 provides a summary of the SNL review insights and recommendations.
I i
l l
l I
1 i
I l
t 2
i j
2.D AN A SSESSMENT OF THE UTILITY RAI RESPONSES 2.1 RAIItem 1: CalculationErrors 2.1.1 BriefStatement ofConcern i
RAI item 1 cited that the utility ampacity calculations reviewed by SNL in April 1996 1
contained a r> umber of errors and questionable assumptions. The USNRC agreed with the SNL recommendation that these calculations should not be credited.
2.1.2 Summary ofUtilityPa=~mse The utility response states that the subject calculations have been " voided firom the design basis of WCNOC."
l 2.1.3 Assessment ofResponse Adequacy This response is fully adequate to resolve the identi6ed concerns. With the abandonment of these calculations by the utility, all the identified technical concerns related to these eclculations which were identi6ed by SNL in its initial review report have been rendered moot.
J 2.2 RAIItem 2: Use ofIndustry Data 2.2.1 BriefStatement ofConcern The USNRC recommended that the utility abandon its calculations, and
- stead rely on m
industry data for an assessment the ampacity dera&g effect.
2.2.2 Summary ofUtilityResponse The utility has followed the USNRC advice, and has based its subsequent evaluations on
~
either TVA or TU test results. It also cited that evaluations for the material Darmatt would similarly be based on manufacturer data for the material.
2.2.3 Assessment ofResponse AM=y,
This response is fully adequate to resolve the identi6ed concerns. The TU and TVA test results cited by the utility have been subject to previous USNRC review, and have been accepted for use by the nuclear 'mdustry.
3
2.3 RAI Item 3: Non-Continuous leads Item I l.*
- 2.3.1 BriefStatement ofConcem The licensee had excluded two conduits from consideration based on non-continuous operation. The USNRC had requested furtherjusti6 cation or supplemental analyses for these two conduits.
2.3.2 Sununary ofUtilityResponse The utility response stated that supplemental assessments were performed assuming a continuous operating condition for the cables, and that the cables were still found to be ec - d h le.
2.3.3 Assessment ofResponse Adequacy l
This response is fully adequate to resolve the identi6ed concerns, although the actual calculations were not available for SNL review.
2.4 RAI Item 4: Triplex Versus Three-Conductor Ampacities 2.4.1 BriefStatement ofConcem RAI item 4 questioned the use of cable ampacity limits for triplex cables in applications apparently involving 3-conductor cables.
i 2.4.2 Summary ofUtility Response The utility response states that the updated analyses have been based on use of the appre; date ampsdty tables for 3-conductor cables.
j-2.4.3 Assessment ofResponse Adequacy L
l.
This response is fully adequate to resolve the identi6ed concerns, although the actual calculations were not available for SNL review.
l 2.5 RAIItem 5: Two-Conductor Conduit Ampacities 2.5.1 BriefStatement ofConcern RAI item 5 had questioned the apparent use of an ampacity limit based on a single conductor cable for an application involving two co-located cables in a single conduit.
2.5.2 Summary ofUtilityR&
The utility response stated that the calculations had been revised as per the USNRC request.
I 4
)
2.5.3 A'**** ment cfResponse Adequacy This response is fully adequate to resolve the identified concerns, although the actual calculations were not available for SNL review.
2.6 RAIItem 6:NEC Percentage FdiLimits 2.6.1 BriefStatement ofConcem RAI item 6 had cited that some of the utility conduits apparently exceeded that maximum percentage 611 criteria established by the NEC.
2.6.2 Summary ofUtility P==aa_*a The utility response cited that the cables in question had been stripped of theirjackets, and that a review of cable fills revealed that all fills were within NEC limits.
i l
2.6.3 Assessment ofResponse Adequacy This response is fully adequate to resolve the identified concerns.
2.7 RAI Item 7: 80% of Open Air Tray Ampacity Limit 2.7.1 BriefStatement ofConcem RAI hem 7 requested that the utility consider the 80% of open air ampacity limit which is imposed on all cable tray ampacities in the ICEA open top cable tray ampacity tables. The item also cited that use of the results from the tests run by TSI using UL facilities was unacceptable to the USNRC.
2.7.2 Summary ofUtility Response The utility response includes an adequate &ametion of the 80% limit question, and does cite that it will no longer use the TSI test results as a basis for its assessments.
2.7.3 Assessment ofResponse Adequacy This response is fully adequate to resolve the identi5ed concerns.
2.8 RAIItem 8: Non-Continuous LoadsItem 2 2.8.1 BrierStatement ofConcern RAIitem 8 had questioned the validity of the assumption ofnon continuous operation on heating circuits which might operate for extended periods under conditions of prolonged cold weather. Analyses for two impacted cases were requested.
5
2.8.2 Summary cfUtility Response l:-
l The utility response indicated that a continuous service analysis was performed, and that the cables for the affected applications were found to have margin in excess of the estimated derating impact.
2.8.3 Assessment ofResponse Adequacy l-This response is fully adequate to resolve the identified concerns, although the actual l
calculations were not available for SNL review.
2.9 RAI Item 9: Non-Continuous Loads Item 3 l
2.9.1 BriefStatement ofConcern l
RAI hem 9 had questioned the validity of the non-continuous operating condition of a l
speci6c MOV cited in the utility analysis. Furtherjusti6 cation or an analysis for this cable l
was requested.
2.9.2 Summary ofUtility Response The utility response stated that a continuous operation based analysis was performed as l
requested in the RAI. This analysis revealed that the cables in question were nominally overloaded when clad with Thenno Lag. The utility went on to cite that the Thermo-Lag barriers had been removed, and where necessary had been replaced by a Darmatt product with a lower derating impact.
2.9.3 Assessment ofResponse Adequacy This response is fully adequate to resolve the identified concems, although the actual calculations were not available for SNL review.
2.10 RAI Item 10: Cable Physical Parameters 2.10.I Brief Statement of Concern RAI item 10 asked that the utility identify the characteristics of the ' cables being analyzed.
2.10.2 Summary ofUtility Response The utihty response does provide a description of the basis for the values used, but does not cite the actual values in the documents reviewed by SNL. WCNOC does state that these values are provided in the revised calculation documents themselves, although these documents were not available for SNL review.
/
6
2.10.3 AssessmentcfResponse Adequacy l
This response is fbily adequate to resolve the ideralfied concerns. The objective of SNLs comments in this regard were to ensure that future reviews would be able to determine the l
values used by the utility in its calculations, and thereby be able to verify the accuracy of the calculations. The utility statement that these values have been provided in the updated calculations is adequate to address this concern.
i l
2.11 RAI Item 11: Under-Voltage Conditions l
2.11.1 Brief Statement ofConcern RAI item 11 had asked the utility to consider potential under-voltage conditions in its l
analyses.
l 2.11.2 SummaryofUtilityPaponse l
The utility response states that such assessments were included in the updated calculations for all constant KVA equipment power cables.
2.11.3 Assessment ofResponse Adequacy l
l This response is fully adequate to resolve the identified concerns, although the actual L
calculations were not available to SNL for review.
i l
l i
l j
l 7
3.0
SUMMARY
OF FINDINGS AND RECOMMENDATIONS Based on a review of the utility response documents as identified in Section 1.1 above, SNL finds that all of the RAI items in the USNRC memorandum of May 21,1996 have been adequately resolved by WCNOC. The fact that the utility is now relying on available i
ampacity derating test results that have previously been reviewed and accepted by the USNRC will ensure that the ampacity loads for cables at Wolf Creek have been given adequate consideration. The utility abandonment ofits origir.al calculations also renders all of SNL's original concerns regarding those calculations moot.
. SNL's initial review did cite that there was significant margin available for all of the power l
cables considered in the original utility calculations. Hence, while the updated calculation documents were not available for SNL review, the overall conclusions ofeeysbiPy made by WCNOC are certainly credible.
I l
l l
i l
l 8
t-