ML20153B189

Safety Evaluation Re Employee Concern Element Rept 218.4(B), Rev 2, Pipe Stress Calculations Widespread Deficiencies within Pipe Stress Calculations

ML20153B189
Person / Time
Site:	Sequoyah
Issue date:	03/11/1988
From:	NRC OFFICE OF SPECIAL PROJECTS
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Download: ML20153B189 (2)

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SE000YAH NUCLEAR POWER PLANT UNITS 1 & 2 SAFETY EVALL'ATION REPORT FOR EMPLOYEE CONCERNS ELEMENT REPORT 218.d(B), REVISION ?

"PIPE STRESS CALCULATIONS WIDESPPEAD DEFICIENCIES WITHIN PTPE STRESS LALCULATIONS" 1.

Subiect Category:

Engineering (20000)

Subcategory:

Pipe Stress Calculations (21800)

Element:

Widespread Deficiencies Within Pipe Stress Calculations (21804)

Concerns:

SON-86-001-01, SON-86-002-01 The basis for Element Report 218.4(B), Revision 2 are Employee Concerns SON-86-001-01 and SON-86-002-01 which questions TVA's evaluations of alternately analyzed piping.

II.

Summary The Employee Concerns Task Group (ECTG) report identified the following issue from the employee concerns:

1.

Alternate analysis is not as detailed as it should be. Although an NCR was created to resolve all discrepancies associated with this analysis method, some discrepancies could remain unresolved beyond startup.

1 III. Evaluation A technicai review of Employee Concerns Element Report 218.d(B), Revision 2 was perfonred by NCT Engineering, Inc. under NRC Contract No. 05-86-156.

The results of this review are summarized in the attached NCT technical evaluation report dated December 6,1987 on Employee Concerns Element Report 218.4(B),

Revision 2 Element Report 218.4(B), Revision 2 found that the employee concerns were valid for Sequoyah at the time they were expressed.

TVA proposed corrective actions to resolve the concerns on alternately analyzed piping at Sequoyah.

The implementation of TVA's corrective actions, as mcdified to address ECTG cements, was found to be acceptable in an ECTG closecut verification comorandum dated May 14, 1987 TVA's alternate analysis progrce has been previously reviewed by the NRC staff as part of the NRC review of the Sequoyah Nuclear Performance Plan.

This previous staff review is the subject of a separate NRC safety evaluation en the alternate analysis program. The previous NRC staff review addressed specific technical issues that required evaluation prior to the restart of

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, Sequoyah.

In addition to these restart issues, TVA cocwitted to evaluate all alternately analyzed piping systems after the Sequoyah restart to demonstrate i

that all design requirements are met for these piping systems.

The NCT review of Element Report 218.4(B), Revision 2 addressed the technical issues that were not specifically addressed by the NRC's evaluation of restart issues, and the acceptability of the resolution of those issues in the TVA long term program. The NCT technical evaluation report found that TVA's proposed corrective actions for the long term program were acceptable.

The staff concurs with the conclusions presented in the NCT technical evaluation report.

The NCT technical evaluation report identified one open issue. The TVA criteria for alternately analyzed piping does not require a themal flexibility evaluation for piping systems with temperatures less than 120 F.

TVA provided a technical justification for this position that was applicable to 2 inch and under diameter piping.

The NCT report recommended that TVA provide additional justification for excluding the thermal analysis (for temperatures less than 120 F) of larger alternately analyzed piping sizes as part of the icng tem program.

IV. Conclusions Based on the review of Employee Concerns Element Report 218.4(B), Revision 2 and TVA's corrective actions, the staff concludes that Employee Concerns SON-86-001-01 and SON-86-002-01 will be adeouately addressed by TVA's alternate analysis program. TVA should provide additional justification for excluding thermal analyses of larce diameter piping systems for tEnperatures less than 120 F in the long tem (post restart) program, i

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