ML20149J677

Forwards Insp Rept 50-263/97-10 on 970623-27.Insp Reviewed Events Surrounding Discovery of Increased Head Loss Across ECCS Suction Strainers.No Violations Identified

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: IR 05000263/1997010 ML20149J677
References
50-263-97-10, EA-97-332, EA-97-333, NUDOCS 9707290038
Download: ML20149J677 (4)

See also: IR 05000263/1997010

Text

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Q

. July 23, 1997

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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M. Wadley 2 July 23, 1997

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This design issue is a violation of 10 CFR Part 50, Appendix B, Criterion lil, " Design

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 j

Actions" (Enforcement Policy), NUREG-1600, Section VH.B.3. This decision was made i

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 l

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 l

containment pressure, beyond that which was considered necessary in order to ensure

adequate NPSH, especial!y for the core spray pumps. l

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 j

regarding this apparent violation is required at this time,

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M. Wadley 3' 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.,

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Nuclear Engineer, MPCA

State Liaison Officer, State

of Minnesota

Distrib,911o_n:

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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 Rill Rill Rill l Rlil

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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

'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.

'

Sincerely, l

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John A. Grobe, Acting Director j

Division of Reactor Safety l

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' Docket No. 50-263

License No. DPR-22

Enclosure: Inspection Report 50-263/97010(DRS)

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cc w/ encl: Plant Manager, Monticello

,

John W, Ferman, Ph.D., ,

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Nuclear Engineer, MPCA  !

State Liaison Officer, State

of Minnesota

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Distribution:  !

Docket File u/enci Rill PRR w/enci A. B. Beach, Rlli w/enci l

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 i

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, LPM. NRR w/enci TSS w/enci DRP w/ enc!

DRS w/enct CAA1 w/enci DOCDESK w/enci

l 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 j

attachment / enclosure "E" <= Copy with attachment / enclosure "N" = No copy-

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