ML20024G293
| ML20024G293 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 06/09/1975 |
| From: | Wachter L NORTHERN STATES POWER CO. |
| To: | |
| Shared Package | |
| ML20024G291 | List: |
| References | |
| A00L-750609, AL-750609, NUDOCS 9102080496 | |
| Download: ML20024G293 (3) | |
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4 UNITED STATES NUCLEAR REGUIATORY COMMISSION NORTHERN STATES POWER COMPANY MONTICELLO NUCLE'.R GENERATING PIANT Docket No. 50- 263 REQUEST FOR AMENIMENT TO OPERATING LICENSE NO, DPR-22 (License Amendment Request Dated June 9,1975)
Northern States Power Company, a Minnesota corporation, requests authorization for changes to the Technical Specifications as shown on the attachments labeled Exhibit A and hhibit B.
Exhibit A describes the proposed changes along with reasons for.the change.
hhibit B is a set of Technical fpecification pages incorporating the proposed changes.
This request contains no restricted or other defense information.
NORTHERN STATES POWER CCEPANY By CMdM V'l J Wachter Vice President, Power Production &
System Operation On this 9th day of June 1975, before me a notary public in and for said County, personally appeared L J Wachter, Vice President, Power Production & System Operation, and iirst being duly sworn acknowledged that he is authorized to execute this document in behalf of Northern States Power Company, that he knows the contents thereof and that to the best of his knowledge, information and belief, the statements made in it are true and that it is not interposed for delay.
A htfJ Add &L-.
DENISE E. BRANAU 3+
le0TARY PUDLIC - MINNESOTA I HENNEPIN COUNTY h
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a 9102080496 750609 PDR ADOCK 05000263 P
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EXHIBIT A MONTICELLO NUCLEAR GENERATING PIANT DOCKET No.
50-263 LICENSE AMENIEENT REQUEST DATED J1EE 9,1975 PROPOSED CHANGES TO TECHNICAL SPECIFICATIONS APPENDIX A 0F PROVISIONAL OPERATING LICENSE NO. DPR-22 Pursuant to 10 CFR 50.59, the holders of provisional operating license DPR-22 hereby propose the following changes to Appendix A Technical Specification 4.3.A.2 (Page 76).
PROPOSED CHANGE l
Replace the sentence, "Each partially or fully withdrawn operable con-trol rod shall be exercised one notch at 1 cast once each week," with the sentence "Each fully withdrawn operable control rod shall be ex-ercised one notch at 1 cast once each week."
REASON FOR CRANGE The above change is requested becauce the current requirement may involve un-necessary thermal cycling of the fuel. Analytical studiec identify a power redistribution with rod exercising, which is most pronounced for movement of partially withdrawn rods.
In keeping with our ob-jectives to minimize fuel duty and thereby reduce the potential for offgas increases, we are requesting that. Technical Specification 4.3.A.2 be changed to eltninate the requirement to exercise partially with-drawn rods weekly.
The change in surveillance frequency is considered justified based on past experience and the surveillance testing which will continue to be done under the proposed Technical Specification.
The weekly surveil-ance frequency on control rod movement, was established somewhat arbit-rally before Monticello vac licensed.
In nearly 5 years of operation,.
approximately 25,000 notch movement tests have been done at Monticello without a singic failure.
The concept of decreasing the required sur-
. veillance f requency with favorable test experience is consistent with other Technical Specifications surveillance requirements.
In a typical BWR fuel cycle approximately 75% of the control rods must be fully with-drawn at the beginning-of-cycle to achieve rated power.
The end-of-cycle objective is to have all control rods fully withdrawn.
The non-power shaping rods are in a disbursed checker-board pattern. On ap-proximately bi-monthly intervals, the rod sequence is changed to give uni-form exposure.
Power chaping rods are then fully withdrawn and alter-nate rods of the checker-board pattern are used for power shaping. There-
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EM!!IBIT A (COS'T) fore, the greatest interval between movements of any rod is approximate-ly 2 months for the proposed surveillance program.
This is unlikely, however, since the partially withdrawn pcser shaping rods control the power Icvel as well as the power shape and must be moved periodically during the bi-monthly interval to compensate for burn-up and to continue to control the power shape. Considering the fact that these movements in themselves meet the intent of the surveillance test the notch move-ments done (assuming the requirement to check all partially withdrawn rods weekly is eliminated) will exceed 757 of the present degree of test-ing at the beginning of cycle, and will approach 1007,at the end of cycle.
The degree of reduction in surveillance is believed to be jus tified by our past experience.
The thning of the requested char.ge is tmportant for 3 reasons.
- First, a monthly surveillance f requency for rnd movement is believed to be sur-ficient for the fully withdrawn control rods. Under the proposed sur-veillance program certain rods could conceivably remain in a given po-sition for approximately 2 months. Experience gained in relaxing the frequency for surveillance of partially inserted rods over the remainder of the current cycle will support such a change in die future.
- Second, at the present time in the Menticelle fuel cycle 80% of all control rods are fully withdrawn.
In the unlikely event that during the remainder of this cycle all partially withdrawn rods fail to insert on demand, the reactor would still become, suberitical.
Even in this extreme condition, the the proposed cLange in surveillance frequency does not represent a sig-nificant hazards consideration.
Third, it has always been the objective of the licensee to establish and maintain a surveillance program which in its best engineering judgment provides the optimum balance between re-liabic, economical service to the area wth the utmost regard to the health and safety of the general public.
Since it is believed that test-ing presently required by the Technical Specifications is not necessary and can lead to increased off-gas emmissions and reduced plant capacity, immediate approval of the above change is urged m meet this objective.
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