ML20040D739

From kanterella
Jump to navigation Jump to search
Final Deficiency Rept Re Indeterminate Surface Finish on Unit 3 South Side Steam Generator Bearing Plates,Initially Reported 811019.Four Plates Replaced Per Design Specs. Receiving Insp Procedure Revised
ML20040D739
Person / Time
Site: Satsop
Issue date: 01/22/1982
From: Leddick R
WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To: Faulkenberry B
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8202020208
Download: ML20040D739 (4)


Text

  • -e Docket Nos. 50-508/509 prV 50 55(e) Report Washington Public Power Supply System Box 1223 E ma, Washington 98541 (206)482-4428 Docket Numbers 50-508 and 50-509 C Y

January 22, 1982 9-flEC5!V'.iG

\j G03-82-068 3 119825 i -

$EN:Y

, =cr$[" ,

U. S. Nuclear Regulatory Commission, Region V g to Office of Inspection and Enforcement 1450 Maria Lane, Suite 260 Walnut Creek, California 94596-5368 Attention: Mr. B. H. Faulkenberry Chief, Reactor Construction Projects Branch

Subject:

PROJECT NOS. 3 AND 5 DOCKET NUMBERS 50-508 AND 50-509 FINAL REPORT OF P0TENTIAL 10CFR50.55(e)

SOUTH STEAM GENERATOR BEARING PLATES, UNIT 3 (D/N #038)

In accordance with the provisions of 10CFR50.55(e), Region V was noti-fied on October 19, 1981 that a potential deficiency, concerning the subject condition, was found.

Attached is a Supply System approved final report that provides a de-scription of the deficiency, an analysis of the safety implications and corrective actions taken. Based on this evaluation, it is con-sidered that the deficiency would adversely affect the safe operations of the plant and, therefore, is reportable as required by 10CFR50.55(e).

Should you have any questions or desire further information, please contact me directly.

R. S. Leddick (1000)

Program Director, WNP-3/5 _

DRC/tt IS Attachment m I:

cc: J. Adams - NESCO-WO/A 'Ii D. Smithpeter - BPA-WO/A ~5 #';fi Ebasco - New york-WO/A 3 WNP-3/5 Files - Richland-WO/A =

Ta

$$ffo![c[0NN $ 5 828

m ATTACHMENT I SOUTH STEAM GENERATOR BEARING PLATES, UNIT 3 (D/N #038)

INTRODUCTION The NSSS steam generators are supported at the bottom by a sliding base bolted to an integrallyf attached conical skirt. The sliding base rests on four (4) low friction bearings which allow unrestrained thermal expansion of the Reactor Coolant System. These bearings slide on smooth surfaces of- the four (4) bearing plates. The design surface finish required for this smooth sliding operation is 125 microinches (MU). Design thermal expansion of the steam generator between cold and hot function is lh".

Chicago ~ Bridge and Iron (CB&I) provided the bearing plates with a 125 MU surface finish. Due to installation tolerances, the plate thickness had to be machined to adjust for the gap. Joint Venture (MK-ESI-Lord) sent these plates to Bingham Willamette machine shop in Portland, Oregon. Bingham Willamette machined these plates to the required thickness but did not attain the 125 >W su.rface finish. Bingham Willamette excluded the surface finish in their Certificate of Compliance. The Joint. Venture received, inspected, accepted and subsequently installed the plates in the as-received condition.

Personnel who performed the document review during receiving inspection failed to recognize that certification of surface finish was not provided

-by Bingham-Willamette.

Bearing plates and Steam Generator No. 2 were installed on the south side of Unit No. 3 during the weekend of August 21-22, 1981.

One week after Generator placement, an NCR was initiated by Joint Venture -

to identify the documentation deficiencies relative to the bearing plate surface finish. The NCR noted that the surface finish of the plates was indeterminate.

Since this could affect the performance of Primary Coolant System, ' the determination of surface finish was essential and the' problem was considered significant.

The NRC was notified on September 20, 1981 in accordance with the provisions of 10CFR50.55(e) and an Interim Report dated November 17, 1981 was issued.

m A. DESCRIPTION OF DEFICIENCY For Steam Generator #2 in Unit 3, the actual surface finish of bearing plates as installed was indeterminate. The installing contractor failed to clearly establish the acceptability of the actual finish through proper documentation prior to installation. After the installation of the steam generator, it was discovered - that the receiving inspection of th'e plates was questionable and the actual conditions of the finishes were indeterminate.

The~' deficiencies are categorized as follows:

., 1) ~Material Deficiency _

2) Inspection Deficiency .

Material Deficiency:

Ebasco design drawing required a 125 MU finish at the top and bottom surfaces of these bearing plates. CB&I provided the plates with the required finish; however, it was necessary to renachine the plates to adjust the thickness to suit the field conditions. Bingham Willamette, under purchase order from Joint Venture, machined the plates to the required thickness, but the 125 MU surface finish was not achieved.

Joint Venture's Audit Report indicated the surface finish varied from 200 MU to 650 MU.

Inspection Deficienqv,:

In the Certificate of Compliance, Bingham Willamette certified the plates but excluded the surface finish 3quirements. A Joint Venture auditor, who audited the shop documents, pointed out in his audit report that the surface finish varied from 200 MU to 650 MU and che plates did not have the surface finish required by the purchase order.

The Joint Venture was aware of the questionable surface finish on these plates as shipped from Bingham Willamette and was prepared to rework the place surfaces at the site if necessary. However, the Joint Venture receiving inspector, using surface plate comparative methods, Judged the surface finish as received to be in compliance with the purchase order requirements and the bearing plates were l

released and installed without rework at the site. The Joint Venture's Receiving Inspection Report indicates that the Bingham Willamette Certificate of Compliance was verified and accepted. However, Bingham Willamette's exception to surface finish requirement in j the Certificate of Compliance was not addressed in the Receiving I

Inspection Report.

l t

l l l

l l

I t

e .

B. SAFETY ANALYSIS The steam generator is connected to Primary and Secondary Coolant Loop piping. These piping systems are designed for a ~ fixed rate of temperature and pressure changes during heat up and cool down cycles. Temperature change and pressure limits are established to assure consistency with the design number of cycles and satisfy applicable stress limits in the components of the Coolant System.

Interface temperatures vary at the primary and secondary system sides.

The thermal expansion of the individual components is designed to be related to 1 " thermal expansion of the Primary Coolant System during hot function. Hence, to accommodate this thermal expansion the sliding surface for the steam generator is very important.

Frictional resistance of the bearing plate is important to the sliding motion of the Steam Generator. The coefficient of friction, between the bearing plates and the sliding base bearings considered in the CE design of the system is based on a 125 HU surface finish of the bearing plates.

If a rougher surface finish is provided, then the coefficient of friction will increase.

This will increase the fricti'onal resistance to the sliding motion of the steam generator, theteby-inhibiting the system from attaining the design intended thermal expansion and this, in turn, will induce additional stresses in both primary and secondary coolant system conponents.

This could adversely affect the design integrity of the entire system and could also adversely affect the safe operation of the plant.

Since the Combustion Engineering (CE) analysis for steam generator sliding is based on a 125 MU finish, any adverse af fects due to varying rougher finish on the sliding surface are indeterminate.

C. CORRECTIVE ACTIONS -

The following actions were taken-to correct the deficiency:

1. Steam Generator #2 was lifted and the four questionable bearing plates were replaced with four new bearing plates having 125 FRJ surf ace finish in accordance with design requirements.

The four removed bearing plates were inspected by Pacific Testing 1.aboratory of Seattle, Wa sh in g t on . 'Iwo plates were found to meet 125 MU rirface finish. Third one vaited from 86.5 MU to 245 MU.

Fourth one varied from 152.5 to 418.5 MU.

2. Joint Venture revised their Receiving Inspection Procedure to include the verification of all reinted documentation at the time of receiving inspection.

1

, _ . _ _ ,,- ---