ML20203E005
| ML20203E005 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 02/05/1998 |
| From: | Richards S NRC (Affiliation Not Assigned) |
| To: | Horn G NEBRASKA PUBLIC POWER DISTRICT |
| Shared Package | |
| ML20203E011 | List: |
| References | |
| 50-298-97-201, NUDOCS 9802260231 | |
| Download: ML20203E005 (6) | |
See also: IR 05000298/1997201
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION
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WASHINGTON, D.C, 20066 4001
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February 5,1998
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Mr. G. R. Hom
Sr. Vice President of Energy Supply
Nebraska Public Power District
141415th Street
Columbus, NE 68601
SUBJECT:
COOPER NUCLEAR STATION - DESIGN INSPECTION
(NRC INSPECTION REPORT NO. 50-298/97-201)
Dear Mr. Hom:
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A design inspection at the Cooper Nuclear Station (CNS) was performed by the Special
Inspection Section of the Office of Nuclear Reactor Regulation (NRR) during the period
October 6,1997, through December 4,1997, including on-site inspections during October 27-
November 7,1997, November 17-21,1997, and December 1-4,1997. The team selected for
- inspection the residual heat removal (RHR) system and the reactor equipment cooling (REC)
system. The purpose of the inspection was to evaluate the capability of the systems to perform
safety functions required by their design bases, tie adherence to the design and licensing bases,
and the consistency of the as-built configuration with the updated safety analysis report (USAR).
The results of this inspection are presented in the enclosed report. The team selected and
reviewed relevant portions of the USAR, technical specifications (TS), calculations, design
criteria documents, drawings, modification packages, surveillance procedures, and other plant
documents.
The team identified that the design change to the REC system for the installation of the filter
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demineralizer in 1991, the associated safety analysis, and the operating procedure did not
address the importance of maintaining water inventory in the closed REC system. The REC
system would not have been able to support its long-term cooling functions in the event of a
design basis accident, because the minimum available volume of water in the surge tank would
have been depleted within a day through the sampling valves that were left open apparently
since the modification was installed in 1991. Your staff isolated the sampling valves, notified the
NRC of the condition, and issued LER 97-014 on December 12,1997, which identified the cause
as a failure to understand the design basis functions of the system.
. Although many calculations reviewed by the team were satisfactory, the team noted that
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nonconservative assumptions and design inputs were used in the calculations for estimating the
RHR pump room temperature and for verifying the capability of the service water (SW) system to
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provide adequate back up cooling for safety-related equipment in the REC system. A night order
was issued to secure one of the RHR pumps if the fan coil unit in that room becomes
inoperable, and SW back-up cooling calculation was revised.
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Mr. G. R. Horn
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February 5,1998
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The 10 CFR 50.59 safety evaluation that was performed for the USAR revision to increase the
RHRSW booster pump room temperature limit to 131'F did not address the consequences of
operator actions required during post accident conditions to prevent exceeding this tempmature
limit.
The effects of failure of air pressure regulators in the instrument air system on air operated
valves had not been evaluated. At the exit meeting , we urged you to excedite this investigation
and promptly perform operability evaluations as required.
Previous NRC inspections had identified weaknesses in factoring instrument uncertainties into
test acceptance criteria and operating procedures. The team noted that the procedure for
moriitoring SW temperature and the surveillance test procedure for RHR pumps did not consider
applicable instrument uncertainties.
The team also identified other issues, such as: weaknesses in performance monitoring of RHR
and REC heat exchangers; an inadequate reportability review of a deficiency in the design of
power sources to RHR heat exchanger vent valves; not including in operating procedures vendor
recommended limitations on RHR pump operation at low flows; and not considering the potential
for pumping post-accident leakage from ECCS to the radwaste system. In addition, the team has
referred four issues identified in the report to the NRR staff for evaluation.
The team noted several discrepancies in the USAR, TS, and system design criteria documents,
The design criteria document (DCD-13) for the RHR system contained severalincorrect
statements that were inconsistent with the current system design.
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Some of the deficiencies discussed above challenged the capability of the systems to perform
their full des:gn bases functions. The contributory causes for these deficiencies appear to be a
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lack of understanding of the design bases of the systems, use of nonconservative assumptions
and design inputs in calculations, and not maintaining control over the configuration of the design
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bases reflected in various plant documents. Where appropriate, your staff took immediate
corrective or compensatory actions to ensure system operability. For other issues, you have
initiated problem identification reports to address required corrective actions. Taking into
consideration your immediate actions, the team concluded at the end of the inspection, that both
systems were capable of pe, forming their safety functions.
As with all NRC inspections, we expect that you will evaluate the applicability of the results of this
inspection and the specific findings to other systems and components throughout the plant.
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- DISTRIBUTION FOR COOPER NUCLEAR STATION - DESIGN INSPECTION REPORT:
. DATED: Februarv 5.1998 -
M9BTISHES)Y
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Mr G. R. Hom -
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February 5,1998
Any enforcement action resulting from this inspection will be handled by the NRC Region IV
office via separate correspondence. Should you have any questions concoming the attached
inspection report, please contact the project manager, Mr. J. R. Has et (301) 415-1336, or the -
l inspection team leader, Mr. S. K. Malur at (301) 415 2963.
. . Sincerely, =
Original sigral by
Darald P. tbrkin FOR
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Sti art A. Richards, Chief _
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E <ents Assessment, Generic Communication,
snd Specialinspection Branch
Division of Reactor Pr9 gram Management
Office of Nuclear Reactor Regulation
Docket No.: 50-298
Enclosure : NRC Inspection Report No.: 50-298/97 201
cc: see next page
DOCUMENT NAME: G:\\skm\\ coverlet.1'
- See previous concurrence
To rec'ive a copy of this document, indicate in the box C= Copy w/o attachment / enclosure E= Copy with attachment / enclosure N = No copy .
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OFFICE
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DATE
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OFFICIAL RECORD COPY
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Mr. G. R. Horn
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Any enforcement action resulting from this inspection will be handled by the NRC Region IV
office via separate corre',pondence. Should you have any questions concerning the attached
- inspection report, please contact the project manager, Mr. J. R. Hall at (301) 415-1336, or the
inspection team leader, Mr. S. K. Malur at (301) 415-2963.
Sincerely,
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Stuart A. Richards, Chief
Evants Assessment, Generic Communication,
and Specialinspection Branch
Division of Reactor Program Management
Office of Nuclear Rer.ctor Regulation
Docket No.: 50-298
Enclosure : NRC Inspection Report No.: 50-298/97-201
cc: see next paoa
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Nebraska Public Power Company
Cooper Nuclear Station
cc:
Mr. John R. McPhail, General Counsel
Lincoln Electric System
Nebraska Public Power Di:trict
ATTN: Mr. Ron Stoddard
P. O. Box 499
11th & O Streets
Columbus, NE 68602-0499
Lincoln, NE 68508
Nebraska Public Power District
MidAmerican Energy
<
ATTN: Mr. J. H. Swailes
ATTN: Dr. William D. Leech, Manager Nuclear
Vice Presider.t of Ne. lear Energy
907 Walnut Street
P. O. Box 98
P. O. Box 657
Brownville, NE 68321
Des Moines, IA 50303-0657
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Randolph Wood, Director
Nebraska Department of Environmental
Nebraska Public Power District
Control
ATTN: Mr. B. L. Houston, Nuclear
P. O. Box 98922
Licensing & Safety Manager
Lincoln, NE 68509-8922
P. O. Box 98
Brownville, NE 68321
Mr, Larry Bohlken, Chairman
Nemaha County Board of Commissioners
Mr. G. R. Hom
5
Nemaha County Courthouse
Sr. Vice President of Energy Supply
1824 N Street
Nebraska Public Power District
Aubum, NE 68305
141415th Street
Columbus, NE6P'ni
Senior Resident inspector
U.S. Nuclear Regulatory Commission
P. O. Box 218
Brownville, NE 68321
Regional Administrator, Region IV
- U.S. Nuclear Regulatory Commission
611 Ryan Plaza Drive, Suite 1000
Arlington, TX 76011
Ms. Cheryl Rogers, LLRW Program Manager
Division of Radiological Health
Nebraska Department of Health
301 Centennial Mall, South
P. O. Box 95007
Lincoln, NE 68509-5007
Mr. Ronald A. Kucera, Department Director
of Intergovemmental Cooperation
Department of Natural Resources
P.O. Box 176
Jefferson City, MO 65102
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