ML20012D723
| ML20012D723 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 03/19/1990 |
| From: | Miller H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Larson C NORTHERN STATES POWER CO. |
| Shared Package | |
| ML20012D724 | List: |
| References | |
| NUDOCS 9003280290 | |
| Download: ML20012D723 (3) | |
See also: IR 05000282/1989029
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MAR 191990
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Docket No. 50-282
Docket No. 50-306
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Northern States Power Company
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ATTN: Mr. C. E. Larson
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Vice President, Nuclear
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Generation
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P. 0. Box 59040
Minneapolis, MN 55459-0040
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Gentlemen:
This refers to the special maintenance team inspection conducted by
Mrs. S. D. Burgess and others of this office on January 8-12 and January 29
through February 2,1990. This inspection covered activities at the Prairie
Island Nuclear Generating Station, Units 1 & 2, authorized by NRC Operating
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Licenses No. DFR-42 and DPR-60. The inspection findings were discussed with
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Mr. L. R. E11ason and others of your staff on February 23, 1990.
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The inspection was conducted during the Unit I refueling outage to assess
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and evaluate your support and implementation of maintenance and engineering
to assure that plant structuras, systems, and components reliably perform
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on demand. Various activities were evaluated to determine if maintenance
and engineering were accomplished, effective, and adequately assessed by your
own quality verification process.
The enclosed copy of our inspection report identifies specific areas examined
during the. inspection. Within these areas, the inspection consisted of a
selective examination of procedures and representative records, . observations,
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and interviews with personnel.
In an attempt to focus on those activities that
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are most risk significant, insights from a Probabilistic Risk Assessment-study,
performed by the NRC, were used to select systems and components important to
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safety.
Overall, the inspection team concluded that maintena'nce was well implemented at
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Praiirie Island Nuclear Generating Station. Section 3.0 of the inspection
report provides a synopsis of the ~ effectiveness of your maintenance programs.
The team identified strengths as well as weaknesses in implementation of the
maintenance programs. The most significant strength of Prairie Island's
maintenance organization lies in its long-term, highly skilled, and dedicated
employees who are backed by a dedicated and knowledgeable engineering and
supervisory staff.
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The most significant weaknesses identified were: (1) the failure to use the
internal deficiency identification program for deficiencies such as the bus bar
. corrosion on the IM transformer and 4.16 kV Bus 11 and 12, and the defective.
1 governor on the #22 turbine-driven auxiliary feedwater pump, (2) lack of
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trending maintenance problems that resulted in undetected repetitive failures
of the #22 rod control motor generator, which exacerbated the two Unit 2
. reactor trips in December 1989; (3) untimely response and action to industry
and NRC notices, which included a 10 CFR 21 notification with potential common
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mode failure of more than 25 motor-operated valves; (4) and instances of
performing modifications and alterations without using the proper process that
resulted in uncontrolled modifications made to a Main Steam isolation check
valve disc / nut assembly.
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During this inspection, certain of your activities appeared to be in violation
of NRC requirements, as specified in the enclosed Notice. A written response
is required.
In accordance with 10 CFR 2.790 of the Commission's regulations,
a copy of this letter, the enclosures, and your response to this letter will oe
placed in the NRC Public Document Room.
The responses directed by this letter and the accompanying Notice are not
subject to the clearance procedures of the Office of Management and Budget
.as required by the Paperwork Reduction Act of 1980, PL 96-511.
We will gladly discuss any questions you have concerning this inspection.
Sincerely.
ORIGINAL SIGNED BY. T. O. MARTIN
H. J. Miller, Director
Division of Reactor Safety
Enclosures:.
1.
2.
Inspection Reports
No. 50-282/89029(DRS);
No. 50 306/89029(DRS)
3.
Appendix A - Acronyms-
See Attached Distribution
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MAR 191990
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Distribution
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E. L. Watzl,-Plant Manager
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DCD/DCB (RIOS)'
Licensing Fee Management Branch
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Resident Inspector, RIII Prairie
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Resident Inspector, RIII Monticello
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- John W.--Ferman, Ph.D.,
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Nuclear Engineer, MPCA
State: Liaison Officer, State
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Commissioner Curtiss, OCM/JC
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K. Hart, NRR/LPEB
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Director / Division of Reactor
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