ML20149J677
| ML20149J677 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 07/23/1997 |
| From: | Grobe J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Wadley M NORTHERN STATES POWER CO. |
| Shared Package | |
| ML20149J679 | List: |
| References | |
| 50-263-97-10, EA-97-332, EA-97-333, NUDOCS 9707290038 | |
| Download: ML20149J677 (4) | |
See also: IR 05000263/1997010
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Q
July 23, 1997
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EA 97-332
EA 97-333
Mr. M. D. Wadley
Vice President,' Nuclear Generation
Northern States Power Company
414 Nicollet Mall
Minneapolis, MN 55401
SUBJECT:
NRC INSPECTION 35. PORT 60-263/97010(DRS) AND EXERCISE OF
ENFORCEMENT OlSCRETION
Pear Mr. Wadley:
On June 27,1997, the NRC completed a specialinspection at your Monticello reactor
facility. The puroose of this insoention was to review the events surrounding your
discovery cf increased head loss across the emergency core cooling system (ECCS)
suction strainers, and the resultant effect upon the available net positive suction head
(NPSH) for the core spray pumps. The enclosed report presents the resulta of that
inspection.
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Arcas examined during the inspection are identified in the report. Within these areas, the
inspection consisted of a selective examination of procedures and representative records,
observationa, and interviews with personnel.
During this inspection, we reviewed an issue involving a past design deficiency which
could have resulted in operating the plant outside of its design bases. The issue involved
the actual head loss across the ECCS strainers, as compared to that specified in the design
bases. This issue was identified by your engineering staff and resulted from a good
questioning attitude and followup by your staff. We noted that the error in the strainer
head loss was made during plant construction and was not likely to have been identified
by routine surveillance or qublity assurance activities. The issue was appropriately
cc,mmunicated to the NRC, and several telephone conversations were held between your
staff and the NRC to assess the significance of the issue. On May 9.1997, your staff
voluntarily shut down the reacter until larger strainers could be insta!!ed. These new
strainers rncet the origiral design requirement for head losa We consider the corrective
actions taken to be comprehensive and apt to prevent recurrence.
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July 23, 1997
This design issue is a violation of 10 CFR Part 50, Appendix B, Criterion lil, " Design
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Control," which could be considered for escalated enforcement and subject to a civil
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penalty. However, af ter consultation with the Director, Office of Enforcement, I hava been
authorized to not issue a Notice of Violation and not propose a civil penalty in this case,!.i
accordance with the " General Statement of Pelicy and Procedure for NRC Enforcement
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Actions" (Enforcement Policy), NUREG-1600, Section VH.B.3. This decision was made
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after consideration that (1) the violation was identified by your strff's good questioning
attitude during a voluntary initiative; (2) ::orrective actions, both taken and planned, were
comp"ohensive and timely; (3) the condition was subtle in nature and not likely to be
disclosed through routine surveillance or qual ty assurance activitias; and (4) the violation
is not s easonably linked to current perforn'ance. The exercise of discretion acknowledges
your good effort to identify and co rect a subtle vielation, that would not be identified by
routine efforts, before the degraded safety system was called ur,nn.
Also during this inspection, an apparent violatinn vvas identified and is being cons:dered for
escalated enforcement action in accordance with the Enforce.nent Pclicy. This apparent
violation concerned use of containment overpressure to ensure adequate NPSH to the
ECCS pumps without prior NRC knowledge or approval. Ti.is issue was first identified
during the safety system operational performance inspection in December 1996, and was
left as an unresolved item in Inspection Report 96000, in May 1997, the NRC determined
that Monticello was not given credit, in its licer: sing basis, to use containment
overpressure to satisfy the NPSH requirements of the ECCS pumps. The NRC's t'oncern
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over the unapproved use of contalumant overpressure was underscored by your staff's
recent recognition of an accident scenario which resulted in a rapid decrease in
containment pressure, beyond that which was considered necessary in order to ensure
adequate NPSH, especial!y for the core spray pumps.
NRC is presently reviewing this apparent violation and you will be advised by separate
ccrrespondent.e of the results of our delit'arations on this matter, in addition, please be
advised that the number and characterization of apparent violatior.s described in the
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er. closed inspection report may change as a result of further NRC review. No response
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regarding this apparent violation is required at this time,
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M. Wadley
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July 23, 1997
in accordance with 10 CFR 2.700 of the NRC's " Rules of Practice," a copy of this lotter,
its enclosure (s), 'und your response (if you choose to provide one) win be placed in the
NRC Public Document Room (PDR). To ttie extent possible, your response should not
include eny personal' privacy, proprietary, or safeguards information so that it can be
' rAaced in the POR without redaction.
Sincerely,
/s/ J. A. Grobe
John A. Grobe, Acting Director
Division of Reactor Safety
~ Docket No. 50-263
License No. DPR-22
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Enchsure:
inspection Repcrt 50-263/97010(DRS)
cc w/ encl:
Plant Manager, Monticello
,
John W. Ferman, Ph.D.,
Nuclear Engineer, MPCA
,
State Liaison Officer, State
of Minnesota
Distrib,911o_n:
Docket File w/enci
SRis, Monticello,
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DRP w/enci
A. B. Beach, Rill w/enci
J. Lieberman, OE w/enci
DRS w/enct
J. L, Caldwell, Rlli w/enct
J. Goldberg, OGC w/enci
Hill PRR w/enci
Rill Enf. Coordinator w/enci
R. Zimmerman, NRR w/enci
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SEE ATTACHED CONQ_URRENCES
DOCUMENT NAME: G:DRS\\ MON 97010.DRS .
Tn' receive a copy of this dr:ument. andicata in the box: "C" = Copy w!o att/enci *E" = Copy wIstt/end
'N' = No copy
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OFFICE
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In accordance with 10 CFR 2.790'of the NRC's " Rules of Practice," a copy of this letter,
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its enclosure ((s), and your responso (if you choose to provide one) will be placed in the
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'NRC Public Document Room (PDR). To the extent possible, year respor.se should not
. include any.personai privacy, proprietary, or safeguards information so that it can be
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placed in the PDR without redaction.
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Sincerely,
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John A. Grobe, Acting Director
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Division of Reactor Safety
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' Docket No. 50-263
License No. DPR-22
Enclosure:
Inspection Report 50-263/97010(DRS)
cc w/ encl:
Plant Manager, Monticello
,
John W, Ferman, Ph.D.,
,
,
"
Nuclear Engineer, MPCA
State Liaison Officer, State
of Minnesota
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Distribution:
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Docket File u/enci
Rill PRR w/enci
A. B. Beach, Rlli w/enci
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PUBLIC IE-01 w/enct
SRis, Monticello,
J. L. Caldwell, Rif t w/enci
OC/LFDCB w>enct
Piairio Island w/ encl
Rlli Enf. Coordinator w/enci
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LPM. NRR w/enci
TSS w/enci
DRP w/ enc!
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DRS w/enct
CAA1 w/enci
DOCDESK w/enci
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J. Lieberman, OE w/enci
J. Goldber0, OGC w/ encl
R. Zimmerman, NRR w/enci
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DOCUMENT NAME: G:DRS\\ MON 97010.DRS
To receive a copy of this document,indicato in the box: "C" = Copy without
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attachment / enclosure "E" <= Copy with attachment / enclosure "N" = No copy-
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