ML17298B879
| ML17298B879 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 01/31/1985 |
| From: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | Kirsch D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| ANPP-31842-MFH, NUDOCS 8502120213 | |
| Download: ML17298B879 (6) | |
Text
RggpplEg I.PQ Arizona Mudear Povver ProJecg; P.o. Box 52034 o
PHoENIx, ARlzoNA85072 2034 Pg Q; REDO'> t/~';~
January 31, 1985 ANPP 31842-$(g~~~
U. S. Nuclear Regulatory Commission Mr. D. F. Kirsch, Acting Director Division of Reactor Safety and Projects Region V
1450 Maria Lane, Suite 210 Walnut Creek, CA 94596-5368 Qi
Subject:
Palo Verde. Nuclear Generating Station (PVNGS) Units 1, 2 and 3
Docket Nos.
STN 50-528 (Lic. No. NPP-34)/529/530 ANPP Response to Design Review questions Pile:
85-056-026 D.4.33.2
Reference:
Letter from E. E. Van Brunt, Jr.
(ANPP) to D. F. Kirsh (NRC), dated December 14, 1984 (ANPP-31473)
ANPP Response to Design Review creations
Dear Mr. Kirsch:
During the review of the pipe stress calculations for the Auxiliary Peedwater System; in conjunction with resolving some concerns of NRC Region V, it was discovered that in some cases the designer did not consider vertical uplift or did not document that vertical, uplift was considered in the design.
Xt appears that the root cause for this condition is an omission, i.e.,
the procedure did not require the evaluation of the vertical uplift in accordance with the project design criteria.
A review of 100 percent of the applicable Unit 1 safety-related supports has been conducted to ensure that there are no safety significant uplift forces which would require modification to the existing pipe supports.
No cases were found where stresses in the pipes exceed allowable code values.
Thus no safety significant condition exists and no field modifications to existing pipe supports are 'required for any of the units.
The results of the analysis appear in Calculation 13-MC-ZZ-547.
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Page 2
In the referenced
- letter, we stated that we had asked Bechtel to determine if errors similar to those found in the pipe stress calculations for vertical uplift could occur in any other project uplift calculations, and if the root cause was transportable to other design calculations.
To determine if the failure, to address vertical uplift forces was generic to other disciplines, those areas where the engineers perform a similar analysis as that done for supports for piping systems were identified.
Our review shows that the only area where this occurs is in the Civil/Structural design of supports for HVAC Duct
- Systems, Electrical Raceway
- Systems, Instrumentation
- Systems, and Equipment Tie Down.
Design calculations and drawings in these areas were reviewed and in all cases it was found that the supports and equipment are designed to withstand uplift forces.
3he review of these items was conducted by engineers on the project who were not directly involved in the original design.
A further check of this review was made by Bechtel Civil/Structural staff personnel who were not directly involved in the PVNGS design process.
Based on the detailed review discussed
- above, we believe that errors similar to the one discovered in the Plant Design discipline have not been repeated in the Civil/Structural calculations.
To determine if this root cause is transportable to other design calculations where the individual design may not have considered all proje'ct approved criteria; a review of sample calculations for each of the various disciplines was conducted.
No errors or omissions in the application of project design criteria were discovered.
3he calculation reviews
- were, for the most
- part, conducted by Senior
- Bechtel, ANPP, or staff personnel.
SUMMARY
1.
Based on the analysis contained in Calculation 13'-ZZ-547, the piping
- systems, as constructed, are safe and no field modifications to existing pipe supports are required for any of the units.
2.
Other project calculations which consider vertical uplift in the design have been reviewed.
Errors similar to those discovered in the Plant Design discipline pipe stress calculations have not occurred in the other project calculations.
Preliminary review of other Bechtel nuclear projects indicates that this root cause is unique to Palo Verde.
- However, a Bechtel Problem Alert is being issued to other projects.
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Page 3
't 3.
Project calculations were reviewed for transportability of the root cause to other design calculations.
As a result of our review of all the disciplines on the project, we have 'concluded that the project approved criteria has been properly implemented.
We believe that all the calculations are correct and in order.
Me believe that this provides sufficient information to close out our action item in the referenced letter and subsequent discussions with the NRC on December 18, 1984, in which we committed to address Xtem 6 of the referenced letter by January 31, 1985.
J Should you require any further information, please advise.
Very truly yours, E. E.
Van Brunt, Jr.
APS Vice President Nuclear Production ANPP Project Director EEVBJr/MAR/dh cc:
E. A. LLcitra R.
Zimmerman J.
Crews NRC Region V A. C. Gehr
AT V
E