ML20148D120

Part 21 Rept Re Replacement Impellers for Byron Jackson Raw Water Pumps Having Blade Dimensions Out of Tolerance Due to Normal Wear on Pump Internals.Replaced Raw Water Pump Assembly AC-10D

ML20148D120
Person / Time
Site:	Fort Calhoun
Issue date:	05/23/1997
From:	OMAHA PUBLIC POWER DISTRICT
To:	NRC
References
REF-PT21-97 NUDOCS 9705300073
Download: ML20148D120 (4)

Text

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n OMAHA PUBLIC POWER DISTRICT j

. NUCLEAR LICENSING DEPARTMENT i

P.O. . Box 399 Hwy. 75 - North of Fort Calhoun  !

Administration Building / Mail Stop: FC-2-4  ;

Fort Calhoun, NE 68023-0399 '

(402) 636-2000 / Switchboard '

(402) 533-7291/ Fax Number -_- -.

FACSIMILE TRANSMITTAL COVER SHEET l s DATE: Ik3h1 NUMBER OF PAGES (Including this Page): 3 ROM:

TO: gg. g <nM g&mx Area Code (402) 533-O Gary Cavanaugh 6913 O Mike Howman 6939 j O Pat Cotton 6935 O Rich Lentz 6918 O Dennis Dryden 7337 O Chuck Linden 8930 LOCATION: O Mike Edwards 6929 .afTom Matthews 6938 O Donna Guinn 6937 O Erick Matzke 6855 O Bill Hansher 6894 O Jim Tills 6868 O O 4

E-MAIL ADDRESS: First Initial Last Name@OPPD.COM  ;

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4 Omaha Public Power District (OPPD)

Report on Nonconforming Raw Water Pump Impellers This report is submitted pursuant to 10 CFR 21.21(c)(3)(1). The items below address the specific information required by 10 CFR 21.21.(c)(4).

(1) Identification of individual providing this notification:

S. K. Gambhir Division Manager - Engineering & Operations Support Omaha Public Power District Fort Calhoun Station P. O. Box 399 Fort Calhoun. NE 68023-0399 (ii) Basic components containing defect:

Replacement impellers for Byron Jackson Raw Water pumps had blade dimensions out of tolerance.

(iii) Identification of supplier:

BW/IP International, Inc.

(iv) Nature of Defect:

Raw Water pump assembly AC-100 was replaced due to normal wear on the pump internals namely the pump impellers and impeller liners. The replacement assembly had been rebuilt with new inter al components After installation.

post maintenance and operability testing was performed using a station procedure. . The pump did not satisfy the acceptance criteria contained in the test: therefore the pump remained inoperable. The fact that the pump did not pass the test was very unusual especially considering the pump was completely rebuilt with all new internal subcomponents. The impeller lift setting was reverified and then the post maintenance / operability test was reperformed. '

Again the pump did not pass the test. so the pump assembly was removed and replaced with a another spare pump assembly.

The " defective' pump assembly was then disassembled for inspection to detennine cause of the extremely poor performance. Upon inspection of the first stage pump impeller. it was noticed that the blade profile was. significantly different when compared to the second stage impeller. At least two of the four blades on the first stage impeller appeared to have a " droop" causing the opening or suction eye between the blades to decrease. The size of the suction  ;

eye for these particular type of pumps has a large influence on the amount of I discharge flow the pump is able to produce. This is because the decreased suction eye size causes the impeller to become extremely inefficient. With the 4

One other replacement impeller in the warehouse was determined to have similar

, deficiencies.

Potential Safety Significance The subject impellers contained dimensional inaccuracies which could not produce pump discharge flows to satisfy acceptance criteria. The estimated reduction of design flow was 20%. The Plant Review Committee conservatively determined that operation of a Raw Water pump AC-10D at the maximum allowable river temperature (90*F) with the defective impeller Installed could have created a substantial safety hazard by exceeding a safety limit or cause a major degradation of essential safety-related equipment, considering a single failure in addition to the degraded performance of AC-100. The river water temperature at the time of discovery was 36*F.

(v) Date informaJ m defect was obtained:

The installation of the replacement pump assembly with the defective impeller and unsuccessful testing was initially identified on April 8.1997. Based on review of an engineering evaluation of this condition. OPPD management conservatively determined that a defect existed on May 22. 1997. The OPPD Vice President with executive authority over Part 21 issues was informed on May 23.

1997.

(vi) Number and Location of components containing defect:

Two defective impellers passed the OPPD receipt inspectior, and were stocked in the warehouse. One of these impellers was used to rebuild a spare pump assembly which was installed as Raw Water Pump AC-100. The supplier has not reported these impeller defects. The existance of other r,1milarly defective impellers from this supplier is unknown to OPPD.

(vii) Corrective action which has. or is being taken:

The defective impellers are being returned to the supplier. Raw Water pump AC-10D was replaced with a rebuilt pump assembly which passed all surveillance test requirements (viii) Advice related to defect to be given to licensees:

None.

TOTAL P.02

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[e POWER REACTOR EVENT NUMBER: 32384 FACILITY: FT'CALHOUN REGION: 4 NOTIFICATION DATE: 05/23/97 i UNIT: '[1] [].[.] STATE: NE NOTIFICATION TIME: 17:50 [ET]

j RX TYPE: [1] CE EVENT DATE: 05/23/97 i

EVENT TIME: 10 : 4 0 [CDT]

NRC EOTIFIED BY: TOM MATTHEWS LAST UPDATE DATE: 05/23/97 ,

i HQ OPS OFFICER: STEVE SANDIN l

<. NOTIFICATIONS l EMERGENCY CLASS: NOT APPLICABLE'

i. 10 CFR SECTION: GARY SANBORN RDO

$- CDEG 21.21 (c)'(3) (i) DEFECTS / NONCOMPLIANCE-VERN HODGE (VIA FAX) NRR UNIT SCRAM CODE RX CRIT INIT PWR INIT RX MODE CURR PWR CURR RX MODE-1 N Y 100 POWER OPERATION. 100 POWER OPERATION EVENT TEXT ]

-THE LICENSEE ISLMAKING A PART 21 NOTIFICATION REGARDING DEFECTIVE RAW WATER PUMP IMPELLERS.

'THE' LICENSEE IDENTIFIED THAT THE REPLACEMENT IMPELLERS FOR BYRON JACKSON RAW WATER PUMPS HAD BLADE DIMENSIONS OUT OF TOLERANCE. AN ENGINEERING.

EVALUATION OF THE DIMENSIONAL INACCURACIES DETERMINED THAT-PUMP DISCHARGE FLOWS-USING THESE IMPELLERS WOULD NOT SATISFY ACCEPTANCE CRITERIA AND COULD POSE A SUBSTANTIAL EETY HAZARD UNDER CSETAIN CIRCUMSTANCES. THIS PROBLEM I WAS INITIALLY IDENTIFIED'ON 4/8/97. THE.TWO DEFECTIVE IMPELLERS WERE RETURNED TO THE SUPPLIER. THE LICENSEE DOES NOT KNOW IF OTHER FACILITIES i ARE AFFECTED. l THE LICENSEE INFORMED THE NRC RESIDENT INSPECTOR.

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