ML20137L083
| ML20137L083 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 01/20/1986 |
| From: | Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | Harold Denton, Rubenstein L Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20137L086 | List: |
| References | |
| 86-047, 86-47, NUDOCS 8601240354 | |
| Download: ML20137L083 (5) | |
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VINGINIA ELECTRIC AND POWEH COM1*ANY l
H IC H M O N D, VI HO INI A 281261 January 20, 1986 W.L.STEWAMT Vice Passinant NecLaam oPEWATIONS Mr. Harold R. Denton, Director Serial No.86-047 Office of Nuclear Reactor Regulation N0/DJV/acm Attn:
Mr. Lester S. Rubenstein, Director Docket No. 50-339 PWR Project Directorate #2 License No. NPF-7 Division of PWR Licensing-A U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Gentlemen:
VIRGINIA ELECTRIC AND POWER g MPANY NORTH ANNA POWER STATION UNIT NO. 2 PROPOSED TECHNICAL SPECIFICATIONS CHANGE Pursuant to 10 CFR 50.90, the Virginia Electric and Power Company requests an ar.endment, in the form of a change to the Technical Specifiestions, to Operating License No. NPF-7 for North Anna Power Station Unit No. 2.
We are requesting this change on an emergency basis per the provisions of 10 CFR 50.91(a) (5).
Failure to act on this request prior to January 23, 1986 will likely result in shutdown of North Anna Unit 2.
We are requesting a change in the surveillance requirement for the end-of-cycle moderator temperature coefficient (MTC) to permit suspension of further MTC measurements once an equilibrium boron concentration (all rods withdrawn, rated thermal power condition) of 20 ppm or less is reached for the current fuel cycle (cycle 4) only.
The equilibrium boron concentration is presently less than 20 ppm.
The proposed change is provided in Attachment 1.
This request has been determined to be acceptable from a nuclear safety viewpoint on the basis that the MTC limiting condition for operation of - 40 pcm/'F will not be reached during the current fuel cycle. This determination was based on calculations and actual MTC measurements and is discussed in more detail in the Safety Evaluation which is provided in Attachment 2.
Relief from the surveillance requiremee. is necessary because no practical means exists to perform the recc. ired measurement at very low boron concentrations.
The standard "bc.on dilution rethod" of measurement is not possible at very low borou concentrations because dilution operations take an extended amount of time which makes MTC measurements highly unreliable due to the many possible fluctuations in system conditions that may take place during the measurement.
Alternate measurement technfques such as control rod insertion are not considered feasible because of the large uncertainty associated with using a reactivity computer for at-power measurements.
Consequently, there would be little confidence in the measured value.
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8601240354 960120 l)l PDR ADOCK 05000339 P
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r VIROIM1A EtzcTalc no Powsa Courawy to Mr. Harold R. Denton Failure to act on this request prior to January 23, 1986 will likely result in plant shutdown due to our inability to perform a suitable measurement of MTC.
The current fuel cycle for North Anna Unit 2 will end on March 15, 1986, which is earlier than the originally planned April 15, 1986 refueling outage. A 48 day outage is then planned for refueling and maintenance as well as certain NRC required modifications.
As we are not yet ready to conduct the outage, premature plant shutdown would cause the outage to be extended at a significant cost to the Company and its customers.
The need for this requested amendment was not recognized in time to permit a normal NRC review and public notice period.
The series of MTC measurements required by specification 4.1.1.4.b has not been required at North Anna during previous fuel cycles, because the end-of-cycle MTC measurement at 300 ppm had always resulted in a value which was satisfactory with respect to the Technical Specifications limit.
Further, reactor physics calculations for this fuel cycle indicated that MTC would be satisfactory at 300 ppm, and there was no expectation of additional testing being required below 300 ppm.
Consequently, the problems associated with measuring MTC at very low boron concentrations were not anticipated.
The 300 ppm MTC measurement for Unit 2 Cycle 4 was taken on October 30, 1985 and MTC was found to be more negative than the - 31 pcm/'F limit.
Station management immediately requested Engineering to evaluate the possibility of changing the Technical Specifications limits to provide greater operating margin for current and future cycles.
At the same time Nuclear Operations Support was requeated to review the MTC test method and to recommend appropriate methods and procedures for testing at very low boron concentrations.
On December 16, 1985, Engineering completed work on a proposed Technical Specifications change request to relax end-of-cycle MTC limits. At about this same time Nuclear Operations Support completed its work on the MTC test procedures, and it became evident that a suitable MTC measurement would be very difficult, if not impossible, once the end of full power, core design life was reached.
Management and safety reviews of the proposed changes to end-of-cycle MTC limits were completed and the request for license amendment was submitted on January 3,1986 (Serial No.85-873).
Discussions were also i
initiated with NRC Region II regarding the difficulties with performing the MTC measurement and our belief that the measurements completed to date provided convincing evidence that the limittng condition for operation has been and will continue to be met during the remainder of Cycle 4.
On January 17, 1986 we were informed by NRC Region Il management that they interpreted l
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vinotutA ELECTRIC AND POWER CCMPANY TO Mr. Harold R. Denton t
North Anna Technical Specifications to require MTC measurements until the end 4
of the. fuel cycle (i.e. shutdown for refueling), and that the Company would have to apply to NRR for emergency Technical Specifications relief.
We are applying for this relief at this time.
This request has been reviewed and approved by the Station Nuclear Safety and Operating Committee and the Safety Evaluation an'd Control Staff.
It has been determined that the proposed change does not involve an unreviewed safety question as defined in 10 CFR 50.59 or a significant hazards consideration as defined in 10 CFR 50.92.
An application fee of $150 is enclosed in accordance with 10 CFR 170.12.
Very truly yours, c,
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,t, W. L. Stewart Attachments 1.
Proposed Technical Specifications Change - North Anna Unit 2 2.
Safety Evaluation cc:
Dr. J. Nelson Grace Regional Administrator NRC Region II Mr. Morris W. Branch NRC Resident Inspector North Anna Power Station Mr. Charles Price Department of Health 109 Governor Street Richmond, Virginia 23219
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4 COMMONWEALTH OF VIRGINIA )
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CITY OF RICHMOND
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The foregoing document was acknowledged before me, in and for the City and Commonwealth aforesaid, today by W.
L.
Stewart who is Vice President Nuclear Operations, of Virginia Electric and Power Company.
He is duly authorized to execute and file the foregoing document in behalf of that Company, and the statements in the document are true to the best of his knowledge and belief.
, 19 ke Acknowledged before me this
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4 ATTACllMENT 1 PROPOSED TECHNICAL SPECIFICATIONS CIIANGE NORTH ANNA UNIT 2 January, 1986 4