ML20106D318
| ML20106D318 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 10/08/1984 |
| From: | Woolever E DUQUESNE LIGHT CO. |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| REF-PT21-84, REF-PT21-85-101-000 2NRC-4-160, 84-09, 84-9, PT21-85-101, PT21-85-101-000, NUDOCS 8502130066 | |
| Download: ML20106D318 (5) | |
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'Af Duquesie Ucjit 2NR9gi6f (412)923-1960 Nuclear Construction Division Telecopy (412) 787-2629 Robinson Ptaza, Building 2. Suite 210 October 8, 1984 Pmsaurgh. PA 15205 United States Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406 ATTENTION:
Dr.' Thomas E. Murley Administrator
SUBJECT:
Beaver Valley Power Station - Unit No. 2 Do cke t No. 50-412 Auxiliary Feedwater Pump Impeller Wear Ring Reportable Significant Deficiency Report 84-09 Gentlemen:
This final report is in reference to the Report able Significant Deficiency relating to the auxiliary feedwater pump impeller west ring the requirenents of 10CFR50.55(e), it is anticipated problem.
Pursuant to that this is a final report and no further reports are anticipated.
DUQUESN2 LIGHT COMPANY By E / J. Woolever Vic.e President SDH/wjs
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Attachment l
cc:
Mr. R. DeYoung, Director (3) (w/a) h Mr. R. Cortland (w/a)
,J Ms. M. Ley, Project Manager (w/a)
J Mr. E. A. Licitra, Project Manager (w/a) y Mr. G. Walton, NRC Resident Ins, actor (w/a)
INFO Records Center (w/a)
NRC Document Control Desk (w/a)
SUBSCRIBED AND JWORN TO BEFORE ME THIS 3 JAY OF [b /((M
,1984.
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. United Stetss Nuclear
- ulstory Commicsion Dr. Thomas E. Murley s
Page 2 COMMONWEALTH OF PENNSYLVANIA ))
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COUNTY OF ALLECHENY
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On this [
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, be fore me, a Notary Public in and for said Commonwealth and County, personally appeared E. J. Woolever, who being duly sworn, deposed and said that (1) he is Vice President of Duquesne Light, (2) he is duly authorized to execute and file the foregoing Submittal on behalf of said Company, and (3) the statements set forth in the Submittal are true and correct to the best of his knowledge.
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~ Notary Public
- WA G. LESONDAK, NOTARY PUBL!C RCBINSON TOWNSHIP, ALLEGHENY COUNTY MY COMMISSION EXPIRES OCTOBER 20,1986 i
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,s United Stetas Nuciocr' guletcry Commission
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Dr. Thomas E. Murlsy Page 3 SDH/wjs NR/MRC/SDR8409 Attachment bec: J. J. Carey (w/ attachment) i J. A. Hultz C. E. Ewing-T. D. Jones T. P. Noonan H. M. Siegel R. J. Swiderski L. E. Arch W. V. Pfroamer R. Coupland D. H. Williams i
J. Pedro (NUS)
C. R. Bishop R. Wittschen P. RaySircar (S&W)
D. Chamberlain (S&W) ""
T. J. Lex (4)
S. Phillips (W)
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NCD File SDR 84-07 File
References:
(1) 2DLC-6952, dated 3/20/84 (2) 2DLC-7411, dated 8/15/84 (3) 2DLS-22895, dated 10/1/84 l
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BEAVER VALLEY POWER STATION - UNIT NO. 2 DUQUESNE LIGHT CDMPANY
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Reportable Significant Deficiency Retort 84-09 Auxiliary Feedwater Pump Impeller Paar Ring 1.
SUMMARY
i was advised by Bingham-Willamette (B-W)
Duquesne Light Company _ (DLC)
Company that an auxiliary feedwater pump at the Palo Verde Nucle ar Ganerating Station had experienced the failure of an impeller wear ring.
I B-W stated that the BVPS-2 auxiliary feedwater pumps (2FWE*P22-turbine driven; 2FWE*P23A and B-motor driven) have a wear ring design and wear j
ring material (AISI 440A spuncast) identical to the Palo Verde pumps.
1 The Palo Verde incident was reported to. the NRC under the provisions of 10CFR21.
B-W classified this failure as an isolated incident and stated that the cause had not been determined.
After this failure, testing of B-W's replacement material was undertaken at Palo Verde.
i B-W of fered to replace the BVPS-2 impeller wear rings, throttle sleeves, j
and bushings with AISI 420 wrought material for the auxiliary feedwater pumps.
B-W's of fer to replace existing' AISI 440A parts to enhance auxiliary feedwater pump reliability, coupled with the experience of cracking of impeller wear rirgs on a BVPS-2 turbine-driven auxiliary feedvater pump (2FWE*P22) in 1981 (SDR 81-04) have raised concerns rega rding the suit-ability of the 440A spuncast material for wear ring application.
4 2.
IMMEDIATE ACTION TAKEN 1
reportability I
As a result of the above concerns, BVPS-2 commenced a evaluation under the requirements. of 10CFR50.55(e).
BVPS-2 decided to proceed with the replacement ~of the impeller wear rings, throttle sleeves, and bushings with AISI 420 wrought parts for the auxiliary i
feedwater pumps (refer to Section 5,
"Correc tive Action to Re.sedy De f iciency").
Mr. S. D. Hall, Acting Manager, Regulatory Af fairs, DLC, notified Mr. Lowell Tripp NRC Region I of fice of this reportable item on September 24, 1984.
t 3.
DESCRIPTION OF THE DEFICIENCY With the except ion of the previous wear ring failure on a turbine driven l
pump, no damage has occurred to the BVPS-2 auxiliary feedwater pumps or j
auxiliary feedwater system.
However, because of the similarity between the BVPS-2 and Palo Verde auxiliary feedwater pumps, the potential for a failure of the BVPS-2 wear rings and a reduction in pump performance /
i reliability does exist.
1 The failure mechanism for AISI 440A wear rings is such that numerou s
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operating cycles are required to obs erve the tendency of the AISI 440A matorist to lose its properties of ductility and malleability.
Physical i
changes in volume also result from the material's tendency to convert
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..f, retained austentite to unt empe red martensite, thus aggravating stress levels in the rings' retaining pins and contributing to further component degradation.
B-W has indicated that wear rings fabricated from AISI 420 wrought material are more reliable than rings fabricated from the AISI 440A spuncast material discussed above.
Extreme endurance testing at Palo of AISI 420 in wear ring design / service by Verde also supports the use demonstrating reliability is higher than for the original AISI 440A material.
4.
_AFALYSIS OF SAFETY IMPLICATION The failure of an impeller ring would most likely result in a degradation o' performance for the af fected pump stage. The presence of metal in the flow path, due to the initial ring failure, could potentially af fect other stages within the pump by causing discharge flow path restrictions.
This could ultimately lead. to a reduction or loss of pumping capacity such that, coincident with another single failure in the auxiliary feedwater system, the plant's. residual heat removal capabilities could be adversely impacted.
The comason-mode failure of impeller wear rings on multiple auxiliary feedwater pumps could also lead to unacceptable i>apacts on residual heat removal capabilities.
5.
CORRECTIVE ACTION TO REMEDY DEFICIENCY
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The auxiliary feedwater pump impeller wear rings, throttle sleeves, and bushings will be replaced by components fabricated with AISI' 420 wrought material.
This replacement ef fort, including reinstallation of the components into the BVPS-2 auxiliary feedwater pumps, is scheduled to be wapleted by December 1,1984.
6.
ADDITIONAL REPORTS This is the final report and no additional reports are anticipated.
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