ML20140G108
| ML20140G108 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 04/30/1997 |
| From: | Caldwell J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Wadley M NORTHERN STATES POWER CO. |
| Shared Package | |
| ML20140G111 | List: |
| References | |
| 50-306-97-06, 50-306-97-6, NUDOCS 9705060388 | |
| Download: ML20140G108 (2) | |
See also: IR 05000306/1997006
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April 30, 1997
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Mr. M. Wadley, Vice President
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Nuclear Generation
Northern States Power Company
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414 Nicollet Mall
Minneapolis, MN 55401
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SUBJECT:
NRC SPECIAL INSPECTION REPORT NO. 50-306/97006 AND
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Dear Mr. Wadley:
On March 17,1997, the NRC completed a special inspection at your Prairie Island Nuclear
Generating Plant. The enclosed report presents the results of that inspection.
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The purpose of this inspection was to review the circumstances of a Unit 2 shutdown
operations event on the night of March 6-7,1997, involving a planned drain of coolant
from the reactor coolant system. Due to a non-licensed operator's valve tagging error, the
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drain was conducted without the system vented. Without an adequate vent path, the
instrumentation that control room operators used to monitor the drain was not
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representative of the amount of inventory drained from the system. Consequently, more
coolant than intended was drained from the system and a gas void developed in the high
points of the reactor coolant system.
Although there was no adverse impact on decay heat removal capability, this event
represents a loss of control of a plant evolution. We identified weaknesses in the
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procedures used for the evolution, your evaluation of the impact of a change in plant
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configuration to establish a vent path, plant configuration control, and interpretation of
available data by control room operators during the evolution.
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Based on the results of this inspection, the NRC has determined that two violations of NRC
requirements occurred. The violations are cited in the enclosed Notice of Violation (Notice)
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and the circumstances surrounding them are described in detail in the subject inspection
. report.
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You are required to respond to this letter and should follow the instructions specified in the
enclosed Notice when preparing your response. The NRC will use your response, in part,
to determine whether further enforcement action is necessary to ensure compliance with
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regulatory requirements.
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9705060388 970430
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ADOCK 05000306
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M. Wadley
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in accordance with 10 CFR 2.790 of the NRC's " Rules of Practice," a copy of this letter
and its enclosures will be placed in the NRC Public Document Room (PDR).
Sincerely,
/s/ J. L. Caldwell
J. L. Caldwell, Director
Division of Reactor Projects
Docket No.: 50 306
License No.: DPR-60
Enclosures:
inspection Report 50-306/97006
cc w/ encl:
Plant Manager, Prairie Island
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John W. Forman, Ph.D.,
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Nuclear Engineer, MPCA
State Liaison Officer, State
of Minnesota
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State Liaison Officer, State
of Wisconsin
Tribal Council
Prairie Island Dakota Community
Distribution:
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Docket File w/ encl
DRP w/ encl
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PUBLIC IE-01 w/ encl
Rill PRR w/enci
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OC/LFDCB w/enct
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SRI Prairie Island w/enci
CAA1 w/enci(E-mail)
Monticello w/ encl
A. B. Beach, w/ encl
Rill Enf. Coordinator, w/ encl
DRS (2) w/enci
Deputy RA, w/ encl
TSS w/enci
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