_- - _ - _ _ _ _ _ _ - _ _ - - _ - - - _ _ _ - - -

,

. .2 l

'.

Northern States Power Company

Prairie Island Nuclear Generating Plant

==,

December 17,1998

U S Nuclear Regulatory CommissionAttn: Document Control Desk'Nashington, DC 20555

PRAIRIE ISLAND NUCLEAR GENERATING PLANTDocket Nos.50-2821.icense Nos. DPR-42

50-306 DPR-60

Follow Up to NSP Letter Dated December 10,1998:Technical Specification Interpretation for

Applicability of Quadrant Power Tilt Limits

in the letter from Northern States Power Company (NSP) to the U.S. NuclearRegulatory Commission (NRC), dated December 10,1998, NSP proposed that PrairieIsland Nuclear Generating Phnt (PlNGP) Technical Specification TS.3.10.C beinterpreted such that, at power levels less than 50% RTP, the Quadrant Power TiltRatio (QPTR) limits of this specification are not applicable. In subsequent conversation,the NRC requested a positive statement that the PINGP core analysis supports theconclusion that QPTR limits need not be applied at power levels less than 50%. Theattached memo from NSP's Nuclear Analysis Department (the organization responsiblefor the PINGP core and transient analysis) provides this positive statement.

In this letter we have made no new Nuclear Regulatory Commission commitments.Please contact Jeff Kivi (651-388-1121) if you have any questions related to this letter.

Ww \ )Joel P. SorensenPlant Manager

hcp\Prairie Island Nuclear Generating Plant

9812230088 981217 i

PDR ADOCK 05000282 i.P PDR L1

'

_ _ _ _ _ _

. . _ . _ . . _ . _ _ . . . . _ . . . ..

*.. .. s..

USNRC NORTHERN STATES POWER COMPANY.

December 17,1998Page 2

|

. c: Regional Administrator - Region 111, NRC' Senior Resident inspector, NRCNRR Project Manager, NRCJ E Silberg

|

Attachment

|

|

I.

i

follow up to CPTR Ts!.DX

. . . _ _ _ _ _ . _ . . _ . _ _ _ _ _ . _ , . . . _ . . _ - _ . . . . _ . . _ . . _ _ _,

1

lt. -, .. - j

ATTACHMENT... ,.

1

i

NSP Internal Correspondence from H O Nelson, NSP- Nuclear Analysis, ;

to Jeff Kivi, Prairie Island, dated December 17,1998

i.

I

I

,

11

,

t .'

1t I

l

! I

i.I

i

i ~

.

k

;

-)

.

N

4

y r- y- r-- w, - .,, -w -- , - , c 4 m--

- . -. .

Int: mal Cortcspondanc3

oat. December 17",1998,.

From H O Nelson tocauon RSQ 10

To Jeff Kivi Location PING

select Technical Specification Interpretation for Applicability of Quadrant Power Tilt Limits

Nuclear Analysis and Design (NAD), which is the organization that has responsibilityfor Prairie island's core and transient analyses, has reviewed the proposed" Technical Specification Interpretation for Applicability of Quadrant Power Tilt Limits"and concurs with the interpretation that the Quadrant Power Tilt Ratio (QPTR)Technical Specification should not apply when the reactor is below 50% rated thermalpower (RTP). The justification for and safety significance of the interpretation isbased on the relevant section in the Prairie Island Technical Specifications andStandard Technical Specifications. This information clearly allows operation below50% RTP while determining the cause of the tilt.

Nothing in any of the core or safety analyses for Prairie Island relies on limiting theOPTR below 50% RTP, Below 50% RTP there is either insufficient stored energy inthe fuel or insufficient energy being transferred to the reactor coolant to require anylimitations on QPTR. Therefore, the OPTR is not a concem for operation of thePrairie Island units below 50% RTP.

Thus, NAD concurs that the justification and safety significance supports theconclusion that the OPTR Technical Specifications do not apply below 50% RTP.

qH O Nelson I

Pi Project ManagerNuclear Analysis and Design

ec: Cliff Bonneau RSQ(10)RO Anderson RSQ (8)Tom Breens Pl