ML032760180
| ML032760180 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 10/03/2003 |
| From: | Reynolds S Division Reactor Projects III |
| To: | Domonique Malone Nuclear Management Co |
| References | |
| EA-03-180, IR-03-005 | |
| Download: ML032760180 (5) | |
See also: IR 05000255/2003005
Text
October 3, 2003
Mr. Daniel J. Malone
Site Vice President
Palisades Nuclear Plant
Nuclear Management Company, LLC
27780 Blue Star Memorial Highway
Covert, MI 49043-9530
SUBJECT:
PALISADES PRELIMINARY WHITE FINDING;
NRC INSPECTION REPORT 50-255/03-05
Dear Mr. Malone:
On March 25, 2003, with the plant in Mode 6 (Refueling), plant maintenance workers were
installing signs in the parking lot designating parking spaces. One of the signposts was driven
into a conduit and damaged a cable which contained a combination of energized indication
circuitry and de-energized protective relay circuitry. The metal signpost cut and shorted
together several of the conductors within the cable which resulted in a loss of offsite power and
loss of shutdown cooling. An Alert was initially declared based on the loss of offsite power
combined with the loss of shutdown cooling and was subsequently downgraded to an Unusual
Event after about one hour when shutdown cooling was restored. Your staff secured from the
Unusual Event on March 27, 2003, when offsite power was reliably restored.
As discussed in NRC Special Inspection Report 50-255/03-05, we reviewed the circumstances
surrounding this event and identified a finding with a significance which was to be determined.
As described in Section 02.2 of the subject report, the finding involved the failure to have
established controls in place in the form of administrative policies and procedures for digging or
excavating activities and the failure to address previous problems involving digging and
excavating activities.
We have recently completed our preliminary assessment of this finding. This finding was
assessed based upon the best available information, including influential assumptions, using
the applicable Significance Determination Process (SDP) and was preliminarily determined to
be a White finding which means the finding has a low to moderate safety significance. This is
due to the increase in initiating event likelihood (IEL) which resulted from the loss of the
preferred source of offsite power and the reliance on the onsite emergency diesel generators to
provide power to needed mitigating systems.
The preliminary significance of the finding is based on a Phase 3 SDP assessment that used
the plant-specific Phase 2 SDP worksheets and assigned a value to the change in IEL based
on a best estimate. The Palisades loss of offsite power event caused by digging on March 25,
2003, was treated as a random, plant-centered event. However, this particular event was the
result of a performance deficiency that would increase the IEL over that which would be
D. Malone
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expected to cause plant-centered occurrences, such as random equipment failures. Therefore,
from a significance determination process viewpoint, the IEL associated with the March 25,
2003, event was treated by the NRC as a new mechanism that should be additive to the loss of
offsite power IEL expected from all other plant-centered causes. The NRC concluded that an
appropriate estimate of the change in plant-centered loss of offsite power IEL, resulting from
this deficiency, was about 1 event in 32.1 years or 3.11 E-2/year. When the change in
plant-centered loss of offsite power event frequency is considered, the resulting change in Core
Damage Frequency value is on the order of 1E-6/year for this finding, or White. To validate this
result, the NRC used the Standardized Plant Analysis Risk (SPAR) model for Palisades. This
model produced results that were consistent with the results using the plant-specific Phase 2
worksheets discussed above.
Before we make a final decision on this matter, we are providing you an opportunity to:
(1) present to the NRC your perspectives on the facts and assumptions, used by the NRC to
arrive at the finding and its significance, at a Regulatory Conference; or (2) submit your position
on the finding to the NRC in writing. If you request a Regulatory Conference, it should be held
within 30 days of the receipt of this letter; and we encourage you to submit supporting
documentation at least one week prior to the conference in an effort to make the conference
more efficient and effective. If a Regulatory Conference is held, it will be open for public
observation. If you decide to submit only a written response, such submittal should be sent to
the NRC within 30 days of the receipt of this letter.
Please contact Eric Duncan at (630) 829-9628 within 10 business days of the date of your
receipt of this letter to notify the NRC of your intentions. If we have not heard from you within
10 days, we will continue with our significance determination and enforcement decision and you
will be advised by separate correspondence of the results of our deliberations on this matter.
In accordance with 10 CFR 2.790 of the NRCs "Rules of Practice," a copy of this letter will be
made available electronically for public inspection in the NRC Public Document Room or from
the Publicly Available Records (PARS) component of NRCs document system (ADAMS).
ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html (the
Public Electronic Reading Room).
Sincerely,
/RA by Patrick L. Hiland acting for/
Steven A. Reynolds, Acting Director
Division of Reactor Projects
Docket No. 50-255
License No. DPR-20
See Attached Distribution
(*See Previous Concurrence)
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DATE
09/26/03
09/26/03
10/02/03
10/03/03
OFFICIAL RECORD COPY
D. Malone
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cc:
J. Cowan, Executive Vice President
and Chief Nuclear Officer
R. Fenech, Senior Vice President, Nuclear
Fossil and Hydro Operations
L. Lahti, Manager, Regulatory Affairs
J. Rogoff, Esquire, Nuclear Management Company, LLC
A. Udrys, Esquire, Consumers Energy Company
R. Remus, Plant Manager
P. Harden, Site Director
S. Wawro, Nuclear Asset Director, Consumers Energy Company
W. Rendell, Supervisor, Covert Township
Office of the Governor
L. Brandon, Michigan Department of Environmental Quality -
Waste and Hazardous Materials Division
Department of Attorney General (MI)
D. Malone
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