Part 21 Report - 1997-411
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.
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