ML20070U053
| ML20070U053 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 03/28/1991 |
| From: | Schnell D UNION ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-88-011, IEB-88-11, ULNRC-2385, NUDOCS 9104080090 | |
| Download: ML20070U053 (5) | |
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MN7 1991 onniv r. achner Eurn(u)N March 28, m" ' ~
e 33 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Station Pl-137-Washington, D.C.
20555 ULNRC-2385 Gentlemen:
DOCKET NUMBER 50-483 CALLAWAY PLANT PRESSURIZER SURGE LINE THERMAL STRATIFICATION
References:
- 1) NRC Bulletin 88-11, dated December 20, 1988
- 2) ULNRC-2084, dated September 28, 1989 3)=ULNRC-2338, dated December 11, 1990 NRC Bulletin 88-11 requested utilities to establish and. implement a program to confirm pressurizer surge line integrity.
The bulletin required utilities to perform the actions summarized below-and inform the staff of the actions-taken to resolve this issue.
Action 1.a. - Perform a visual-inspection (ASME, Section-XI, VT-3).
Action 1.b. - Perform a plant specific or generic bounding analysis to demonstrate-the surge line meets applicable-design codes and other FSAR and regulatory commitments for the design. life of the plant.
'If the analysis does not demonstrate compliance with these requirements, submit.a-or bring the justification for continued operation (JCO) implement plant to cold shutdown, as appropriate and actions 1.c. and 1.d. to develop a detailed analysis.
Action 1.c.-
Obtain-data on thermal stratification, and line deflect'ons either by plant thermal stri inging or through collective-efforts among--
specific mon tor p? ants with a similar surge line design.
-Action 1.d. - UpdateLdetailed stress and fatigue analyses-of the-surge line to ensure compliance with applicable code requirements incorporating any observations from 1.a.
The analysis should be based on the applicable plant t
specific or-referenced data.
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U.S.
Nuclear Regulatory Commission Page 2 March 28, 1991 Action Items 1.a.,
1.b.,
and 1.c. were completed as described in Reference 2.
In order to address Action Item 1.d.
Union Electric participated in a program for resolution of this issue through the Westinghouse Owners Group (HOG).
The WOG program provided a methodology for a gca9ric detailed analysis based on ASME stress and fatigue ovr..;.uations of groups of plants.
The results of the generic detaileo vali-f:
- r. ru documented in WCAP-12639, " Westinghouse Owners
- o..
Prossurizer Surge Line Thermal Stratification Go-es.ic Detailed Analysis Program Summary Report".
This :CAF was transmitted to the NRC on August 3, 1990 and in a subsequent meeting in November 1990, the NRC indicated acceptance of the technical content of the WCAP and the WOG program.
Union Electric performed additional plant specific analysis of the surge line piping and Reactor Coolant System (RCS) loop nozzle to further verify the applicability of the generic detailed analysis.
The verification analysis was performed using the methodology described in WCAP-12639 and WOG surge lino monitoring data.
In addition to the monitoring data, plant operating procedures and previous heatup and cooldown data were utilized to support this analysis.
The results of this analysis, entitled " Structural Evaluation of the Wolf Creek and Callaway Pressurizer Surge Lines, Considering the Effects of Thermal Stratification " identify the maximum equation 12 stress as 51.5 ks1 for past operation and 47.9 ksi for future operation.
The Codo allowable stress is 57.9 ksi.
Additionally, the analysis resulted in a calculated cumulative usage factor of 0.4.
The Codo allowable usage factor is 1.0.
This analysis also evaluated pipe supports for the stratification loads and displacement and the results were in accordance with ASME Section III Subsection NF.
Pipewhip rostraint gaps and pipe displacement were evaluated and were found to be acceptable.
The results of this analysis have been incorporated into the callaway stress and fatigue reportt.
The pressurizer nozzle was not within the scope of evaluation required by this bulletin.
The pressurizer nozzle at Callaway is oriented vertically, and therefore does not experience local stratification effects.
In the performance of the required surge lino evaluation it was identified that thermal stratification in the pip 1ng t
l typically causes higher global bonding moments at the i
pressurizer nozzle than considered in the original design.
The WOG generic detailed analysis did not address the affects of stratification on the stress and fatigue of the pressurizer nozzle.
However, the plant specific stress j
and fatigue analysis for the Callaway pressurizer nozzle shows that the nozzle loads are in the acceptable range.
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U.S.
Nuclear Regulatory Commission Page 3 March 28, 1991 Based on the WOG generic detailed analysis and the Callaway plant specific analysis, Union Electric has demonstrated that the pressurizer surge line meets the applicable design codes and regulatory commitments for the licensed life of the plant.
Documentation associated with this program is being maintained at Callaway Plant and is available for review by the NRC staff.
If you have any questions concerning this letter, please contact me.
Very truly yours, l
S-
. ? p A u 'r:
,,g Donald F.
Schnell DPS/WRC/RDA/TEH/RJL/WEK/ dis
STATE OF MISSOURI )
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Alan C, Passwater, of Inwtul age, being first duly sworn upon oath snyn that he is Manager, Licene.ing and Fuels (Nuclear) for Union Electric Company; that he han rend the foregoing document and knows the content thereof; that. he has execu ted the name for and on behalf of said company 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.
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By.h
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Alan C.
Pannwater Manager, Licensing and Euela Muclear this.2[.b-_
day SUBSCRIDED and sworn to before me o f _ _ 41<h 1991.
L BARBARA J. PFA NOTARY PUlluC, STATE Of MISSOURI MI C0mssich EXPtRES april. 22, 1993 ST. LOUIS COUNTY i
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Shaw, Pittman, Potts & Trowbridge 2300 N.
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Washington, D.C.
20037 Dr.
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Cermak CFA, Inc,.
(Suite 110) 4 Professional Drive Gaithersburg, MD 20879 R'
C.
Knop Chief, Reactor Project Branch 1 U.S.
Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, Illinois 60137 Bruce Bartlett Callaway Resident Office U.S.
Nuclear Regulatory Commission RRif f Steedman, Missou11 65077 1
M.
D.
Lynch (2)
Office of Nuclear Reactor Regulation U.S.
Nuclear Regulatory Commission 1 White Flint, North, Mail Stop 13E21 11555 Rockville Pike Rockville,.MD 20052 Manager, Electric Department Missouri-Public Service Commission P.O.
Box 360 Jef ferson Ci ty, MO 65102 i
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