ML18033B378
| ML18033B378 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 05/31/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18033B375 | List: |
| References | |
| NUDOCS 9006210239 | |
| Download: ML18033B378 (10) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, O. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION EMPLOYEE CONCERN SUBCATEGORY REPORT 21800 -PIPE STRESS CALCULATIONS TENNESSEE VALLEY AUTHORITY 1.0 STATEMENT OF EMPLOYEE CONCERNS Employee Concerns Subcategory Report 21800 addresses employee concerns with the adequacy of piping stress calculations for safety-related piping for all TVA nuclear power plants.
The report contains the results of TVA's evaluation of 22 separate employee concerns.
In the employee concerns report 3 of the 22 were identified as specific concerns with Browns Ferry.
The remaining 19 concerns were evaluated for applicability to Browns Ferry.
2.0
SUMMARY
The employee concerns subcategory report grouped the 22 concerns into 13 individual elements.
These elements involved both general areas of concern such as deficiencies with pipe stress calculations and more specific concerns such as thermal stress range calculations.
Some of. the elements were further divided into individual issues.
The employee concerns report identified that 6 of the 13 individual elements contained issues that were valid for Browns Ferry.
The issues that were valid for Browns Ferry included the three employee concerns that were specific to Browns Ferry.
3.0 EVAL'UATION TVA's corrective actions for the six individual elements that were considered valid for Browns Ferry are summarized in the subcategory report.
Several of the corrective actions rely on ongoing TVA programs, described in the Browns Ferry Nuclear Performance Plan, to implement the corrective actions.
The staff's evaluation of TVA's corrective actions for each individual element applicable to Browns Ferry are discussed in the following paragraphs.
Element 218. 1 contains six employee concerns regarding TVA's thermal analysis of piping at Watts Bar and Sequoyah.
The subcategory report identified that one employee concern, IN-85-039-001, was applicable to Browns Ferry.
The employee concern dealt with the lack of proper consideration of the thermal stress range in the piping analyses.
The subcategory report found that TVA's alternate analysis criteria for Browns Fer ry did not require the stress range evaluation for either thermal expansion or thermal anchor movement stresses.
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tation, the subcategory report identified a concern with an inadequate definition of thermal modes for the analysis of piping at Browns Ferry.
TVA's proposed corrective action was to formally document thermal modes for all safety-related piping at Browns Ferry and to incorporate these thermal modes in the IE Bulletin 79-14/79-02 and small bore piping analysis programs.
The staff considers the proposed corrective action adequate to address the employee concerns regarding analysis documentation and definition of thermal modes.
The staff has reviewed TVA's programs to generate piping calculations and documented the results in Inspection Reports 50-260/89-15, 50-260/89-36 and 50-260/89-44.
Based on the review of the program plans and their imple-mentation, the staff concludes that these plans will adequately address the employee concern when their implementation is complete.
Element 218.6 contains an employee concern regarding deficiencies in piping analysis at Watts Bar.
The subcategory report found that the concern was not app1icable Co Browns Ferry; Even though the subcateoory report found the concern was not applicable to Browns Fer ry, TVA's programs to generate design calculations for piping systems did address Che genera1 employee concern with piping stress analysis deficiencies.
In addition, one of the issues identified for Watts Bar was a concern with the piping rigid range response.
This issue was specifically addressed by the staff at Browns Ferry for the rigorous piping analysis effor t.
Based on the review of TVA's programs to generate design calculations for piping systems, the staff concludes that these programs will adequaCely address the employee concern when their implementation is complete.
Element 218.7 contains an employee concern with the criteria used on Watts Bar for handling the boundaries (overlap regions) between piping analysis problems.
The subcategory report found the issue was valid for Browns Ferry.
TVA's proposed corrective action was to develop overlap criteria for incorporation into the Browns Ferry rigorous analysis handbook.
In addition TVA's corrective action required the issue Co be addressed in the implemen-tation of TVA's IE Bulletin 79-14/79-02 and small bore piping programs.
The staff considers the proposed corrective action adequate to address the employee concern.
Implementation of TVA's IE Bulletin 79-14/79-02 program was reviewed during two NRC team inspections and the results documented in Inspection Reports 50-260/89-15 and 50-260/89-44.
Based on the review of TVA's IE Bulletin 79-14/79-02 program, the staff concludes that the program will adequately address the employee concern when it has been completed.
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Element 218.8, contains one employee concern with the modeling of a specific piping analysis problem for Watts Bar.
The subcategory report that the concern was only applicable to Matts Bar and that no corrective action was required at Watts Bar.
Since this employee concern was related to a specific Watts Bar piping problem mode),
the staff agrees with the subcategory report conclusion that the issue was only applicable to Watts Bar.
Element 218.9 contains one employee concern with clearances for thermal expansion in the annulus area.
The subcategory report found the issue was valid and only applicable to Watts Bar.
Since Browns Ferry is a BMR design, the plant does not have an annulus area similar to Watts Bar.
Even though the subcategory report found the concern was only applicable to Matts Bar, TVA has initiated a clearance program for Browns Ferry.
Implementation of the Browns Ferry clearance program is an open item in Inspection Report 50-260/89-44, The staff concludes
- that, pending adequate implementation of the Browns Ferry thermal clearance program and resolution of the inspection report open item, the employee concern with clearances for thermal expansion will be adequately addressed at Browns Ferry.
Element 218. 10 contains one employee concern regarding the deformation of specific pipe support stanchions at Watts Bar.
The subcategory report found that the employee concern was only applicable to Watts Bar and it was not valid.
Even though the subcategory report found that the specific concern was not applicable to Browns Ferry TVA has performed detai'led as-built walkdowns and evaluations of pipe supports during the implementation of the IE Bulletin 79-14/79-02 program.
Therefore, the general concern deficiencies with pipe support attachments and their evaluation should have been identified and corrected at Browns Ferry.
Hosea on the review of TVA's IE Bulletin 79-14/79-02 program, the staff concludes that the concern with the as-built evaluation of pipe supports will be adequately addressed at Browns Ferry.
Element 218.11 contains two employee concerns regarding differences between the building input used in the piping analysis and the actual support attach-ment point.
The subcategory report found the concerns valid for Watts Bar and Bellefonte and not applicable to Browns Ferry.
However, even though the subcategory report found the concerns were not applicable to Browns Ferry TVA's IE Bulletin 79-14/79-02 program is addressing both the issue of appro>>
priate building spectra and building deflection in the piping analysis effort.
Based on the review of TVA's IE Bulletin ?9-14/79-02
- program, the staff concludes that the employee concerns with spectra input and building detections will be adequately addressed at Browns Ferry.
Element 218.12 contains an employee concern regarding the control of temporary supports at Browns Ferry.
The subcategory report found the concern valid for Browns Ferry Unit 3 RHR system.
The subcategory report also stated a similar condition exists on Browns Ferry Unit 1.
The corrective actions involve a walkdown and evaluation of the Unit 3 RHR system and a revision of TVA's Modifications and Additions Instruction (MAI)-23 to improve the control of modifications of pipe supports.
The staff considers the proposed cor~ective action adequate to control future modifications.
In addition, TVA's detailed as-built walkdowns performed during the IE Bulletin 79-14/79-02 program should have identified all temporary supports at Browns Fer ry Unit 2.
Based on TVA's proposed corrective actions and the review of TVA's IE Bulletin 79-14/79-02
- program, the staff concludes that the employee concern will be adequately addressed at Browns Ferry.
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0 Element 218.3 contains one employee concern regarding
.the movement of the Browns Ferry drywell purge piping during a design basis accident event.
The subcategory report found the concern was valid for Browns Ferry.
The corrective action required one support to be removed from the Unit 2 piping and one support to be removed from the Unit 3 piping.
TVA stated that this work was accomplished under ECNs P2146 and P2092.
In addition, TVA plans to conduct a clearance program prior to Browns Ferry Unit 2 restart.
Imple-mentation of this program is an open issue in Inspection Report 50-260/89-44.
Based on TVA's completed corrective actions and pending adequate implementation of the Browns Ferry thermal clearance program, the staff concludes. that the employee concern will be adequately addressed at Browns Ferry.
- 4. 0 CONCLUSION Employee Concerns Subcategory Report found that six of the thirteen elements evaluated contained issues that required corrective actions at Browns Ferry.
The proposed corrective actions rely, in part, on TVA programs to regenerate piping design calculations and resolution of the open issues from NRC's inspections of these programs.
TVA has initiated several programs to address deficiencies identified with the design and installation of safety-related piping at Browns Ferry.
The implementation of these programs has been reviewed during three NRC inspections.
The staff has reviewed.
TVA's proposed corrective action plans for the employee concerns and concludes that, with proper implementation during the Browns Ferry piping analysis
- programs, the programs will provide an adequate resolution of the concerns applicable to Browns Ferry described in Employee Concerns Subcategory Report 21800.
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