ML20238C870
| ML20238C870 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 12/23/1987 |
| From: | Varga S Office of Nuclear Reactor Regulation |
| To: | FLORIDA POWER CORP. |
| Shared Package | |
| ML20238C873 | List: |
| References | |
| NUDOCS 8712310293 | |
| Download: ML20238C870 (7) | |
Text
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7590-01 l
UNITED STATES OF AMERICA 1
l NUCLEAR REGULATORY COMMISSION In the l'atter of
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)
FLORIDA POWER AND LIGHT
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Docket No. 50-302 C0f'PANY, et. al.
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(Crystal River
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Unit 3)
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EXEMPTION I.
Florida Power Corporation, et. al. (FPC, the licensee) are the holders of Facility Operating License No. DPR-77, which authorizes operation of Crystal River l' nit 3 (CR3, the facility) at steady-state power levels net in excess of 2544 rregawatts thermal. The license provides, among other things, that the facility is subject to all the rules, regulations, and Orders oT the Nuclear Regulatory Commission (the Commission) now or hereafter in effect.
The facility is a pressurized water reactor (PWR) located at the licer.see's site in Citrus County, Florida.
II.
General Design Criterion-17 (GDC-17) requires that the onsite power supply (diesel generators) for nuclear plants be of sufficient capacity and capability to assure that (1) specified acceptable fuel design limits and design conditions of the reactor coolant pressure bcundary are not exceeded as a result of antici-pated operational occurrences, and (2) the core is cooled and containment integrity and other vital functions are inaintair.ed in the event of postulated accidents. NRC Safety Guide 9 (and subsequently Regulatory Guide 1.9) describes pu2188?i!8B8ljg2 P
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k a basis for selection of a diesel generator of sufficient capacity to implement i
It indicates that predicted diesel generator loads should not exceed the lower of the 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> rating or 90 percent of the 30 minute rating.
III.
An inspection recently performed by the staff identified discrepancies between the surveillance requirements of the Technical Specifications (TF) and the manufacturer's reconnendations related to the diesel generator ratings.
In reviewing this situation and verifying loads, the licensee identified an error j
in the load calculations. Diesel generator loads were recalculated using con-servative best estimates based on actual equipment configuration for each accident scenario and, after deleting certain unnecessary loads, it was deter-mined that for all accident scenarios except two, na imum diesel generator loads fcr one of the two energency diesel gererators, generator "A", would be within the 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> rating. The two scenarios, invching large and inter-mediate size loss-of-coolant accidents (LOCAs), loss of offsite power, and failure of either diesel generator "B" or emergency feedwater pump "E", result in calculated auto-connected loads of approximately 3228 KW. Although this is in excess of the 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> rating, it is within the 30 minute rating of the diesel ganerator. Certain auto-connected loads not needed for these scenarios can ar.d will be naruelly tripped prior to 30 minutes. Dropping these leads will reduce the load demand on generator "A" to a level within the 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> rating.
The auto-connected loads in the original plant design were below the 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> rating of the diesel generators. However, loads have been added to the diesel generators, the largest of which is the electric emergency feedwater pump motor, added after the THI-? accident. This additional load has resulted in generator "A" being loaded in the 30 minute rating.
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By letter dated December 14, 1987, the licensee requested a temporary exemption from the requirements of GDC-17, in accordance with 10 CFR 50.12(a),
l until the next scheduled refueling outase.
In that letter, the licensee referenced its letter dated November 16, 1987 and the information transmitted therewith. The licensee's letter of December 16, 1987 further describes testing to be perfomed which will suppcrt this request for exemption. The licensee's letter of November 20, 1987 describes alternatives the licensee is examining to bring the facility in compliance with Gl'C-17, and commits to submit to the Commission by March 30, 1988 its proposed actiors.
This case involves special circumstances as set forth in 10 CFR 50.12(a)(2)(v). The exemption will provide only temporary relief until the end of the next refueling outage, by which time the licensee is to be in full compliance with GDC-17, and the licensee has made a good faith effort to comply with GDC-17.
Promptly upon identifying the problem of diesel generator capacity, the licensee undertook a number of analyses and design modifications in order to reduce auto-connected loads on the diesels to levels acceptable for long-term operation. Although the licensee has been able to reduce load estimates to within the 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> rating of generator "B" and to within the 30 minute rating of generator "A", it has not been able to reduce autc-connected loads to within the 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> rating of generator "A".
Specifically, the licensee:
removed loads not required for safety from the diesel while retaining required loads, employed adequately conservative scenario-based load analyses, provided additional guidance, procedures, and training to the plant operators to pemit timely and effective load management, and
d-designed automatic load control features which wculd have prevented exceedance of the 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> rating but which were determined by the staff to be undesirable for other reasons.
Compensatory n+asures and features proposed and cormitted to by the licensee to be conpleted before exceeding 5% power and to be in effect during the temporary exemption period include the following:
(1) Control rcom alarms have been providea which will alert the operators initielly when the diesels are operating in the 30 minute rating and again when 5, 24, and 29 minutes of that period have expired.
(2) Operators are well-trained in the facility's symptom-based emergency cperating procedures and will receive additional training and guidance to better equip them to manage diesel generator loads by tripping those which are not required for any particular scenario in order to bring the loads within the 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> rating in a timely manner. The licensee has stated that when load management is necessary, a dedicated operator will be available to accomplish that function.
(3) Individual loads will be tested to verify the calculated values and the diesel generators will be tested to denionstrate their ability to handle the expected accident loads.
I On the following basis, the staff concludes that operation of the facility with the diesels functioning in the nanner described above, including the additionel compensatory r(asures discussed, provides a level of safety for the period of the exemption equivalent to that provided by compliance with GDC-17.
. (1) The exen:ption is only temporary in nature, lasting about ?4 months until the next refueling outage.
(?) The auto-connected load demand exceeds the ?000 hour0 days <br />0 hours <br />0 weeks <br />0 months <br /> rating of diesel generator "A" only for two very unlihely scenarics.
(3) The pctential loss of offsite power occurring simultaneously with such unlikely scenarios is remote.
(4) The low probability cf simultaneous loss of diesel generator "B" or emergency feedwater pump "B" reduces risk eten further.
(5) The compensating measures described above include measures to assure that loads not needed to ccpe with the accidents imposing the greates' demand can and will be dropped while generator "A" is still within its 30 minute rating.
The licensee has supplied reliability assessments which indicate that the probability of simultaneous occurrence of all the failures necessary to produce the highest load on diesel generator "A" is between 10 and 10-8 This further supports the staff's conclusion that an adequate level cf safety exists for the duration of the exemption.
IV.
Based on the above and on our review of the licensee's submittals, the staff concludes that:
(1) the licensee's load calculations are acceptable, provided they are confirmed by valid tests, (?) loads not needed to mitigate any particular design basis accident scenario can be tripoed within 30 n.inutes to bring the load on the "A" diesel generator to within the 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> rating, and (3) the diesel generators will remain operable so that accident consequences
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previously analyzed will not be affected by this exemption. The NRC staff therefore finds the proposed teriporary exemption froni the requirements of l
CDC-17 of Appendix A to 10 CFP Part 50 to be acceptable.
Accordingly, the Contrission has deterniined that, pursuant to 10 CFR 50.12, this exenption is authorized by law, will not present an undue risk to the public health and safety, and is consistent with the comon defense and security.
The Concission further determines that special circumstances, as provided ir 10 CFR 50.12(a)(2)(v), are present justifying the exemption, nonely that the exemption would provide only temporary relief from the applicable regulation and that FPC has made a good faith effort to comply with the regulations.
Therefore, the Commission hereby approves the following exemption from the requirements of GDC-17:
The facility rnay operate with predicted loads for diesel generator "A" within the 30 minute rating of the diesel generator for not rnore than 30 minutes, provided that (1) the principal estimated loads are confirrred by test as described in the licensee's letters dated November 16, l
1987, December IA,1987 and December 16,1987, and (2) operators are trained, l
and alarms and procedures are provided as dectribed in the licensee's letters dated Novenber 16 and December 14, 1967, and, when required, a dedicated operator will be available for load management. This exemption shall expire at the end of the next refueling outage.
Pursuant to 10 CFR 51.32, the Conmission has deterinined that granting this exemptien will have no significant effect on the environment (52 FR 48351, December 21,1987).
For further details with respect to this action, see the licensee's request dated November 14, 1987, as supplemented November 20, December 14 and December 16, 1987, which are available for public inspection at the Contrissien's L_______-_____________-___-
a Public Documer,t Roem, 1717 H Street, NW., Washington, DC 20555 and at the Crystal River Public Library, 668 N.W. First Avenue,. Crystal River, Florida 32629.
This exerrption is effective upon issuance.
F R THE NUCLEAR REGULATORY COMMISSION l
i
/Tkeven ga, i
Division of Reactor r jects-I/II Office of Nuclear Rea or Regulation Dated at Bethesda, Maryland this 23rd day of December,1987 1
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