ML20076F628
| ML20076F628 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 08/16/1983 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, NCR-1589, NCR-1596, NUDOCS 8308260105 | |
| Download: ML20076F628 (4) | |
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TENNESSEE AL E NUTHf)RITY CH ATTANOOGA. TENNESSE d /4
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August 1, 1983 U.S. Nuclear Regulatory Coimaission Region II Attn: Mr. James P. O'Reilly, Regional Administrator 101 Marietta Street, NW,. Suite 2900 Atlanta, Georgia 30303
Dear Mr. O'Reilly:
BELLEFONTE NUCLEAR PLANT UNIT 1 - REACTOR COOLANT IMPELLER TO SHAFT
. MISMATCH - BLRD-50-438/81 FINAL REPORT The subject deficiency was initially reported to NRC-0IE Inspector R. V. Crlenjak on September 17, 1981 in accordance with 10 CFH 50.55(e) as NCRs 1589 and 1596. This was followed by our interim reports dated October 20 and December 29, 1981, July 2, and November 10, 1982 and February 7, 1983 Enclosed is our final report.
In our previous reports TVA has combined NCR's 1589 and 1596. Please note that although we are finalizing NCR 1589 we do not now consider NCR 1596 adverse to the_ safe operation of the plant. Therefore, we will amend our records to delete the subject nonconformance as a 10 CFR 50.55(e) item.
If you have any questions concerning this matter, please get in touch with R. H. Shell at FTS 858-2688.
Very truly youre, TENNESSEE VALLEY AUTHORITY j
Dsu L. M. Mills, Manager
- Nuclear Licensing l
Enclosure oc (Enclosure):
i Mr. Richard C. DeYoung, Director Office of Inspection and Enforcement j
U.S. Nuclear Regulatory Cormnission l
Washington, D.C.
20555 i
j Babcock & Wilcox Company P.O. Box 1260 i.
Lynchburg, Virginia 24505 l.
Attention:
It. J. Ansell y WY I
8308260105 830816 PDR ADOCK 05000438
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.d83-TVA SOTH ANNIVERSARY l
An Equal Opportunity Employer I\\
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ENCLOSURE BELLEFONTE NUCLEAR PLANT UNIT 1 REACTOR COOLANT PUMP IMPELLER TO SHAFT MISMATCH NCRs 1596 AND 1589 BLRD-50-438/81-61 10 CFR 50.55(e)
FINAL REPORT Description of Deficiency -
NCR 1589 During testing conducted 'by the pump vendor (Bingham-Willc mette, Portland, Oregon, hereafter refered to as Bingham), the impoller for reactor coolant pump 1P1A2 expanded slightly because of thermal effects. To correct this condition, the vendor removed some material from the impeller. The removal of this material resulted in improper dimensional contact for the impeller shaft and restriction sleeve, which prevents acceptable fitup of the impeller to the shaft.
This deficiency does not exist for the other three unit 1 reactor coolant pumps.
Proper impeller-shaft fitup has not yet been verified at the plant site for the unit 2 pumps; however, the vendor has confirmed that of the eight Bellefonte reactor coolant pumps (four per unit), only the impeller for pump 1P1A2 was reground. The shaft for unit 2 pump 2P1A1 was returned to the vendor for remachining because it lacked a keyway. This condition was documented by NCR 1388.
NCR 1596 Onsite review of the vendor's data package for reactor coolant pump 1P1A2 revealed discrepancies in the the documentation for posttest inspection. The data package states that the impeller taper was reground and the impeller refit before shipment; but in actuality, the impeller was never refit. These deficiencies resulted from inadequate Laspection by TVA's Quality Engineering Branch (QEB) to verify and document proper fitup after regrinding the impeller.
Safety Implications NCR 1589 The purpose of the pump flywheel is to provide inertia to ensure a slow decrease in coolant flow following a loss of pump power to prevent fuel damage caused by fuel pin departure from nucleate bs iling. If the deficient pump was put into service, the loose fit between tae shaft and impeller would have prevented adequate flow from being achieved during coastdown. This condition would have prevented the pump from performing its intended safety function, and thereby, adversely affected safe operations of the plant.
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I NCR 1596 l
B&W investigated. this matter with Bingham quality assurance (QA) to determine if the shaft / impeller fitup was performed as described in the QA data package. B&W's investigation verified that there are no discrepancies in the documentation of post-perfbrmance test inspection in the QA data package for reactor coolant pump 1P1A2. Therefore, no revised documentation is required.
The events related to this NCR, as determined by B&W's investigation, are as follows:
A.
Following performance testing of pump 1P1A2, the shaft was reground in the area of the impeller taper.
B.
Subsequent to this operation, liquid penetrant examination was perfbreed.
This is verified by page 391 of QA data package (B&W document No. 23-1209-01), item 3 C.
To determine the amount of contact bAtween the shaft and impeller, a trial fitup with " bluing" applied was perfbrand. The degree of contact was sufficient; however, the titup was done without the restriction bushing in place, thus creating an artifically acceptable assembly. It cannot be determined why this happened.
D.
With the shaft / impeller fit seemingly proper, these parts were disassembled, packaged, and shipped to the plant site.
E.
Upon site assembly, the looseness of the impeller was detected, and the parts were returned to Bingham.
F.
At Bingham, the parts were reworked, properly refit together, packaged,'
and returned to the plant site.
Consequently, there are no safety implications to Bellefonte, and TVA no longer considers this item to be reportable under 10 CFR 50.55(e).
Corrective Action The shaft, impeller, and restriction bushing for pump 1P1A2 were returned to the vendor fbr rematching. At Bingham, the misfit was corrected by rework of the impeller and restriction bushing. The parts were properly refit together and returned to the plant site. At the site, proper fitup was again verified when the impeller and shaft were installed in the pump.
Action Taken to Prevent Recurrence In this case, TVA's Quality Engineering Branch (QEB) regional office did not 4
inspect the rework of the shaft, nor did they witness the reassembly or fitup of the impeller to the ground shaft. It is customary that the TVA inspector visually examine surfaces to be mated, but QEB missed this notification and thus did not detect that the fitup was done without the restriction bushings being in place.
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To prevent similar nonconformances at Bingham in the future, QEB has instructed their regional office to make every effort possible in the future to examine and/or monitor the rework of all bearing parts from Bingham prior to reassembly and shipment to TVA. These increased surveillance activities by QEB should result in the elimination of the type of nonconforming condition identified in these NCRs. Also, as a result of this concern, TVA audited Bingham's QA program ~ and uncovered deficiencies which were reported to NRC as audit 83V-10, deficiency No.1.
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