ML20246P055
| ML20246P055 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 05/12/1989 |
| From: | George Thomas PUBLIC SERVICE CO. OF NEW HAMPSHIRE |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NYN-89062, NUDOCS 8905220071 | |
| Download: ML20246P055 (5) | |
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~ New Hampshire emoe s.momos V6ce President Nuclect Production NYN-89062 May 12, 1989 United States Nuclear Regulatory Commission Washington, DC 20555 Attention: Document Control Desk References a) Facility Operating License NPF-56. Docket No. 50-443 b) Commission Decision CLI-88-10 dated December 21, 1988
Subject:
Information on New Hampshire Yankee Methods for Compliance with the'O.75 EFPH Restriction on Low-Power Testing Gentlemen:
In Reference (b) the Commission stated that a low-power license for Seabrook Station Unit 1 should be conditioned to permit no more than 0.75 effective full power hours of operation without additional Commission approval. The NRC Staff has requested information concerning the New Hampshire Yankee methods and programs that will be utilized to measure core exposure. The responses to the Staff's questions are provided in the enclosure.
Should you require further information on this matter, please contact Mr. Robert E. Sweeney in our Bethesda Licensing Office at (301) 656-6100.
Very truly yours, 4%yCh N
G orge f'. Thomas Enclosure
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8905220071 890512 PDR ADOCK 05000443 J
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l New Hampshire Yankee Division of Public Service Company of New Hompshire I
P.O. Box 300
- Seabrook, NH 03874
- Telephone (603) 474-9521 I
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United States Nuclear Regulatory Commission May 12, 1989
- Attention: Document Control Desk Page 2 cca-Mr. William T. Russell Regional Administrator United States Nuclear Regulatory Conunission Region I 475 Allendale Road King of. Prussia, PA 19406
'Mr. Victor Ner'ses, Project Manager Project Directorate I-3 United States Nuclear Regulatory Commission Division of Reactor Projects Washington, DC 20555 NRC Senior Resident Inspector P.O. Box 1149 Seabrook Station, NH 03874
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ENCLOSURE TO NYN-89062 ANSWERS TO NRC QUESTIONS REGARDING 0.75 EFPH CORE EXPOSURE LIMIT BACKGROUND The process that will be s smd-to determine core exposure during the low power test' program will be identical to that used to determine core exposure during normal plant operation. However, instead of using a secondary calorimetric to normalize the power range nuclear instruments, a primary calorimetric will'be used to normalize the intermediate range (IR) nuclear instruments. 'The primary calorimetric will be based on the full power core temperature rise (core AT).
Reactor power will be raised to 3% (based on core AT) and the IR detector currents will be recorded.
The normalization constr.nts for each intermediate range detector (amps /% power) will be determined from this data.
A process computer program has been written to record the IR detector currents and the time between program executions.
The computer program utilizes this data along with the IR detector normalization constants to calculate core exposure.
SPECIFIC QUESTIONS (1) How are you going to determine reactor power level?
- How will you measure the reactor power level?
- How accurately can it be measured?
Response
Reactor power will be measured using the core temperature rise normalized to the full power core temperature rise (commonly referred to as AT power).
The IR detector ovaputs will then be normalized to the measured core AT power.
It will be necessary to normalize the IR detectors to track core exposure because most of the low power testing is conducted in the zero power test range where core AT is essentially 0*F, but the IR detectors are producing a current equivalent to approximately 0.01% power.
-To offset the uncertainties associated with the measurement of core AT, a f
full power core AT of 57.0*F is used to determine the IR detector normalization constants. A full power core AT of 57.0*F is conservative with respect to the expected full power value of 59.4*F.
The procest
-f normalizing the IR detector output to match core AT power also nonm;'
out any uncertainties associated with the IR detector outputs.
Thua, the IR detector outputs simply inherit the error associated with the core AT measurement which has already been accounted for.
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,e (2) Are you going to be able to adquately calibrate instruments needed for this program with the imposed operating restrictions?
Response
All instruments necessary to monitor core exposure are calibrated with the exception of the IR detector output normalization.
IR detector normalization will be performed during normal plant startup regardless of any core exposure limitations.
(3) What tests are you going to perform?
- What power levels will they be done at?
- Do you have a plan and schedule for expending the 0.75 EFPH7 Reponse The tests to be conducted are primarly low power physics tests and a natural circulation test (reference FSAR table 14.2-5 sheets 16 through 22).
The majority of the low power physics tests are conducted in the zero power test range (approximately 0.01% power).
Low power flux mapping will be conducted at approximately 1% power and the natural circulation test will be conducted at approximately 3% power.
There is no specific plan or schedule for expending the 0.75 EFPH.
The Startup Test Program provides the low power test sequence which is calculated to be completed within the allotted exposure limit.
(4) How will you measure the accumulated power with respect to the 0.75 EFPH restriction?
Response
A computer program has been written to calculate core exposure.
All pertinent documentation related to this program (functional description, software, test package) is available for NRC review at Seabrook Station.
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(5) Jow are~you going'.to ensure that you will stay within the imposed operating restrictions?. What document record will be kept of-the EFFH7
Response
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An administrative procedure has been written to ensure that the, exposure limit will not'be exceeded and.to document core exposure.
This procedure is available at Seabrook Station for NRC review.
(6) What happens if.the MPCS'is-inoperable?
- Will the reactor be operated?
Response
The administrative procedures that tracks and documents core exposure contains.a section'on manual tracking of core exposure if the plant computer is unavailable.
(7) Will any kind of calorimetric power calibration be made?
Response
Please see the background statement and the response to question number.1.
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