United States Nuclear Regulatory Commission - Protecting People and the Environment


ACCESSION #: 9705300073



                       OMAHA PUBLIC POWER DISTRICT

                      NUCLEAR LICENSING DEPARTMENT

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

               Administration Building / Mail Stop: FC-24

                       Fort Calhoun, NE 68023-0399

                      (402) 636-2000 / Switchboard

                       (402) 533-7291 / Fax Number



                    FACSIMILE TRANSMITTAL COVER SHEET



DATE:               NUMBER OF PAGES (Including this Page):



TO:                 FROM:     Area Code (402) 533



                    [ ]  Gary Cavanaugh 6913      [ ]  Mike Howman  6939

                    [ ]  Pat Cotton     6935      [ ]  Rich Lentz   6918

                    [ ]  Dennis Dryden  7337      [ ]  Chuck Linden 6930

LOCATION:           [ ]  Mike Edwards   6929      [ ]  Tom Matthews 6938

                    [ ]  Donna Guinn    6937      [ ]  Erick Matzke 6855

                    [ ]  Bill Hansher   6894      [ ]  Jim Tills    6868



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

                                        (JTILLS@OPPD.COM)



COMMENTS:



                   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-10D 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

          internal 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 determine 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

          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



          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 degrees 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-10D.  The

          river water temperature at the time of discovery was 36 degrees

          F.



(v)       Date information of 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 inspection 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-10D.  The supplier has not reported these

          impeller defects.  The existence of other similarly 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.



POWER REACTOR                                         EVENT NUMBER: 32384



FACILITY: FT CALHOUN     REGION: 4      NOTIFICATION DATE:  05/23/97

UNIT: [1] [ ] [ ]          STATE: NE    NOTIFICATION TIME:  17:50 [ET]

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

                                        EVENT TIME:         10:40 [CDT]

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

HQ OPS OFFICER:          STEVE SANDIN

                                                  NOTIFICATIONS

EMERGENCY CLASS: NOT APPLICABLE

10 CFR SECTION:                              GARY SANBORN        RDO

CDEG 21.21(c)(3)(i)      DEFECTS/NONCOMPLIANCE

                                             VERN HODGE (VIA FAX) NRR



UNIT SCRAM CODE IRX CRIT INIT PWR INIT RX MODE    CURR PWR  CURR RX

MODE

1       N           Y      100     POWER OPERATION   100      POWER

                                                              OPERATION



                               EVENT TEXT



THE LICENSEE IS MAKING 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 SAFETY HAZARD UNDER CERTAIN

CIRCUMSTANCES.  THIS

PROBLEM WAS INITIALLY IDENTIFIED ON 4/8/97.  THE TWO DEFECTIVE

IMPELLERS

WERE RETURNED TO THE SUPPLIER.  THE LICENSEE DOES NOT KNOW IF OTHER

FACILITIES ARE AFFECTED.



THE LICENSEE INFORMED THE NRC RESIDENT INSPECTOR.



*** END OF DOCUMENT ***



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