L-86-468, Forwards Response to IE Compliance Bulletin 86-003 Re Single Failure Vulnerability in Min Flow Recirculation Line of Any ECCS Pump That Could Cause Failure of More than One ECCS train.Long-term Resolution of Problem Under Evaluation
| ML20214D692 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 11/14/1986 |
| From: | Woody C FLORIDA POWER & LIGHT CO. |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| IEB-86-003, L-86-468, NUDOCS 8611240211 | |
| Download: ML20214D692 (8) | |
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P. O. BOX 140C0, JUNO BE ACH, F L 33408 s\\i!//
FLORIDA POWER & LIGHT COMPANY NOVEMBER 14 1986 L-86-468 Dr. J. Nelson Grace Regional Administrator, Region 11 U. S. Nuclear Regulatory Commission 101 Marietta Street, N.W., Suite 2900 Atlanta, Georgia 30323
Dear Dr. Grace:
Re: Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 IE Compliance Bulletin 86-03 Response Florida Power & Light Company has reviewed IE Compliance Bulletin 86-03 and our response for Turkey Point Units 3 and 4 is attached.
As noted in the Bulletin, Turkey Point plant had reported this situation in LER 250-86-28, incorporated corrective actions and had previously prepared a justification for continued operation.
Should you or your staff have any questions on this matter, please contact us.
V ry truly yours, r
O. Woo y roup Vice President Nuclear Energy COW /RG/gp Attachments cc:
Document Control Desk, USNRC Harold F. Reis, Esquire I
8611240211 861114
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STATE OF FLORIDA
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J. W. Dickey being first duly sworn, deposes and says:
That he is Vice President of Nuclear Operations of Florida Power & Light Company, the Licensee herein; That he has executed the foregoing document; that the statements made in this document are true and correct to the best of his knowledge, information, and belief, and that he is authorized to execute the document on behalf of said Licensee.
h J. W. Dickey Subscribed and sworn to before me this
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6 NOTARY PUBLIC, in and for the County of Palm Beach, State of Florida ROTARY F0FLIC STATE CF FLORIDA PV CC#4!SSIO4 DP SEPT 18,1983 My Commission expires: ' " U ' * " At !"3 N -
RESPONSE TO IE COMPLIANCE BULLETIN 86-03 This Bulletin requested the licensees to perform four actions.
1.
Promptly determine whether or not your facility has a single-failure vulnerability in the minimum flow recirculation line of any ECCS pump that could cause a failure of more than one ECCS train.
FPL Response:
IE Information Notice 85-94 initially identified a potential for loss of minimum flow paths leading to ECCS pump damage during a LOCA, in December,1985.
Turkey Point performed on evoluotion, and determined that the High Head Safety injection (HHSI) Pumps were subject to the above failure mode. An engineering review, which was completed on October 21, 1986, identified no other ECCS pumps which are subject of the the failure mode identified in this Bulletin.
2.
If the problem exists:
(a) promptly instruct all operating shif ts of the problem and measures to recognize and mitigate the problem; (b) promptly develop and implement corrective actions which bring your facility into compliance with GDC 35.
FPL Response:
Upon identification of the problem, the plant implemented engineerin;;
recommendations which blocked the HHS1 Pump's minimum flow recirculation volves in the open position. This provided a temporary resolution to the concern raised by the Bulletin, and the safety evaloution performed by engineering showed that this would not involve any unreviewed 'sofety questions, provided administrative controls were in place to ensure that the blocks would be removed prior to the recirculation phase. Training briefs 105 and I12, identifying the concerns and actions to be taken, were issued at that time. Simultaneously, on evaluation in accordance with 10 CFR Part 21 was initiated. Upon conclusion of this evaluation, on June 30,1986, a Licensee Event Report (LER 250-86-028) was filed identifying the design deficiency as raising the potential for the loss of minimum flow for the HHSI pumps with consequent pump failure in more than one train, and the temporary measures which were taken (see above). Also, at the tima, FPL completed a Justification for Continued Operation (JCO), which is attached.
3.
Within 30 days of receipt of this Bulletin, (a) provide a written report to the NRC which identifies whether or not this problem exists at your facility,(b) if the problem exists (or existed), include in the report the justification for continued operation and identify the short-term modifications to plant operating procedures or hardware that have been or are being implemented to ensure safe plant operations.
RG3/007/2
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FPL Response:
This report is being submitted in order to meet the requirements of section (a) above. Please see the ottoched Justification for Continued Operation (JCO), in partial fulfillment of the requirements of section (b) above.
The hardware modifications consisted of blocking the offected volves in the open position. The procedural changes consisted of revising several procedures to provide for the removal of the block assemblies and closure of the offected volves prior to the plant entering the recirculation phase.
4.
If the problem exists (or existed), provide a written report within 90 days of receipt of this Bulletin informing the NRC of the schedule for long-term resolution of this and/or any other significant problems that are identified as a result of this Bulletin.
FPL Response:
The long-term resolution of this item is under evoluotion.
Engineering will provide Plant Change / Modification packages prior to the next refueling outages.
FPL will provide the schedule for the full implementation of the resolution as soon as a schedule is developed, with the schedule to be provided no later than January 6,1987.
RG3/007/3
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e SUBSTANTIAL SAFETY HAZARDS EVALUATION FOR THE POTENTIAL LOSS OF MINIMUM SAFETY INJECTION PUMP FLOW TURKEY POINT UNITS 3 AND 4 A
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Background
By Information Notice No. 85-94 (reference 1), NRC identified specific instances where minimum flow requirements might not be met for some emergency core cooling system (ECCS) pumps under smallereak loss-of-coolant-accident (SBLOCA) conditions. One of the cases identified involves Point Beach Units 1 and 2, Westinghouse plants of the same vintage as Turkey Point Units 3 and 4.
Power Plant Engineering has been requested (Reference 2) to review the concern identified at Point Beach against 10CFR21 for Turkey Point Units 3 and 4.
At Point Beach, the SI pumps have a common return pipe from their discharges to the refueling water storage tank (RWST) to provide a test flow path and a i
recirculation path for minimum flow when the RCS pressure exceeds pump shutoff head (see Reference 1). There are two isolation valves in series on the return line for each train. ney are air-operated and fall closed when their control circuits lose electrical power or upon loss of air pressure, which is not supplied from a safety related system. De purpose of these valves is to isolate the RWST (outside containment) from the containment sump during the recirculation phase of emergency core cooling following a LOCA. De valve position indication and the valve closed annunciation in the control room are powered from the same breaker as the valve control circuit. Therefore, the single failure of the breaker associated with either train would isolate the minimum flow path for both SI pumps, defeat the control room annunciation of the valve closure, and cause the loss of valve position indication. Because the valve position indication is not on a front panel, this condition could remain unnoticed for as much as a month (the surveillance interval). Subsequent start of the SI pumps could then result in the failure of both pumps within a short period unless RCS pressure dropped below the 1470 psi shutoff head.
l Evaluation At Turkey Point, four (4) safety injection pumps are available for both units with two associated with each unit. All four pumps are started on an SI signal from one unit and can feed either unit. The SI pumps associated with each unit have a common pipe from their discharges to the RWST to provide a recirculation path for minimum flow. Like Point Beach, there are two isolation valves in series (one for each train) on the return line. These valves are air operated and fall closed on loss of electric power (DC) or instrument air (non-safety related).
Therefore, should a SBLOCA, or other event causing slow RCS depressurization occur, with a loss of instrument air, the minimum recirculation flow path for the Turkey Point SI pumps would be lost. Should a delay occur-between SI and RCS pressure dropping below Si pump shutoff head, pump failure may occur.
c.
Justification for Continued Operation Continued operation of Turkey Point with the potential for loss of safety injectior. is considered justified for the following reasons:
1)
Although instrument air is non-safety related and is not loaded on the DG, numerous self-contained air compressors are available on site. These units which do not require EDG power can be quickly connected to supply compressed air to these valves if needed.
2)
Indication of recirculation valve position is available to the operator on the main control board.
An abnormal valve position indichtion would be l
noticed during shift change control board walk down.
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A temporary modification has been performed to assure the availability of a recirculation flow path for the SI pumps (i.e., valves blocked open).
l Administrative controls will assure closure of these valves should the need for a containment recirculation exist.
4)
Permanent plant modifications to correct this condition are being pursued on an expeditious basis.
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Conclusions in the event of a SBLOCA with a slow decrease in RCS pressure, an SI signal will occur at 1715 psig. With the slow decay in RCS pressure, a delay will occur before RCS pressure drops below the Si pumps shutoff head (1450) psig).
Assuming a loss of instrument air, no recirculation flow will be available.
Therefore, the potential exists for loss of all safety injection due to pump failure.
Loss of all SI pumps represents a Substantial Safety llazard in accordance with 10CFR21.
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