ML20065L724
| ML20065L724 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 08/27/1993 |
| From: | Cruse C BALTIMORE GAS & ELECTRIC CO. |
| To: | Martin T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| NUDOCS 9404210244 | |
| Download: ML20065L724 (4) | |
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GAS AND ELECTRIC CALVERT CLIFFS NUCLEAR POWER PLANT 1650 CALVERT CLIFFS PARKWAY
- LUSBY, MARYLAND 20657-4702 CHARLES H CRUSE August 27,1993 Pt. ANT GENERAL MANAGEA CALVEHf CUFFS U. S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 A'ITENTION:
Mr. T. T. Martin, Administrator
SUBJECT:
Cal [ert Cliffs Nuclear Power Plant Unit No.1; Docket No. 50-317 Recuest for Enforcement Discretion: Calvert Cliffs Unit 1 Baltimore Gas & Electric Company (BG&E) hereby requests discretionary enforcement of Unit No.1 Technical Specification (TS) 3.7.6.1, " Control Room Emergency Ventilation System," _ to allow cleaning of Unit 2 Service Water Heat Exchanger No. 22. We request that we be allowed to operate Unit I for two hours with both Control Room emergency ventilation systems inoperable before applying TS 3.0.3. We believe that this is the safest course of action because it avoids the potential safety consequences of unnecessary plant transients and the accompanying operation risks and impacts.
The situation requiring this action is temporary and nonrecurring and cleaning of the heat exchanger at i
power does not present any significant safety concerns.
REOUIREMENT FOR WHICH DISCRETION IS REOUFSTED t
Technical Specification 3.7.6.1, " Control Room Emergency Ventilation System," requires that two air conditioning units be operable. If one air conditioning unit is inoperable, it must be restored within 7 days or the plant must be shut down.
The Calvert Cliffs Control Room emergency ventilation system (CRHVAC) has two air conditioning units. One unit (No.11) is powered from a Unit I emergency bus and the other (No.12) is powered from a Unit 2 emergency bus.
We request discretionary enforcement of the LCO to allow power operation of Unit No. I for two hours under the circumstances described below.
1 CIRCUMSTANCES SURROUNDING TIIE NEED FOR ENFORCEMENT DISCRETION Calvert Cliffs Units 1 and 2 are both at full power operation.
Currently, the No.11 air condition unit is inoperable and both Unit I and Unit 2 are in a 7 day Action statement leading to plant shutdown. The No.11 CRHVAC was taken out of service for maintenance on Tuesday, August 24. The maintenance has been completed but post-maintenance testing has not 9404210244 930827 PDR ADOCK 05000317 P
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' Mr. T. T. Martin, Administrator August 27,1993 Page 2 been completed. That testing will take over 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to perform. De Action statement for the No.11 CRHVAC ends on Tuesday, August 31, at 05:15 a.m.. We foresee no problem in returning the No.11 CRHVAC back to service before that time.
He differential pressure limit for the Service Water heat exchangers is a function of, among other things, inlet water t smperature. The inlet water comes from the Chesapeake Bay. The measured oifferential pressure across the No. 22 Service Water heat exchanger is very close to the limit and the limit may drop over the weekend as Bay temperature, increases. Normally, we would remove the heat exchanger from service and clean it. Cleaning takes approximately I hour. However, the No. 22 Service Water heat exchanger supports operation of Emergency Diesel Generator No. 21 which is the emergency power supply for the No.12 CRHVAC.
The No. 22 Service Water heat exchanger can be removed from service and Unit 2 can enter TS 3.0.5 for two hours prior to beginning a shutdown. This is sufficient time to clean the heat exchanger and return it to service. However, Unit I cannot enter TS 3.0.5 because it is a Unit 2 power supply that is out of service. He BASES for TS 3.0.5 state, "His specification delineates what additional conditions must be satisfied to permit operation to continue, consistent with the ACTION statements for oower sources, when a normal or emergency power source is not operable * (emphasis added). Unit I would be in no Action statements for power sources and, therefore, TS 3.0.5 cannot be applied. If the heat exchanger were taken out of service, Unit I would enter TS 3.0.3 wbich allows only 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> to correct the condition. Voluntary entry into TS 3.0.3 for maintenance is not permitted.
We request a two hour discretionary enforcement of Unit 1 LCO 3.7.6.1 which will be used in parallel with application of the two hour Action in TS 3.0.5 for Unit 2. His will be sufficient time to clean the heat exchanger and restore No.12 CRHVAC to operable status.
SAFETY SIGNIFICANCE / POTENTIAL CONSEOUENCES The shared Control Room for Units 1 and 2 will still have a CRHVAC unit capable of performing its safety function for events not involving a loss of offsite power. Specifically, when the No. 22 Service Water heat exchanger is taken out of service, the emergency power supply (No. 21 Emergency Diesel Generator) will be inoperable. However, the likelihood of a loss of offsite power during the two hour period is small. We are confident that the actions needed to return No. 21 Emergency Diesel Generator to service can be completed within the two hour action time given in TS 3.0.5.
The maintenance on No.11 CRHVAC has been completed and the unit is functional. It has run for over 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. However, it has not completed formal post-maintenance testing in accordance with our procedures and is not considered operable.
While Unit I will legally have no operable CRHVAC units for two hours, there will be two CR3VAC units available for use. One is functional, but not tested. De other is functional, but does not have an ernergency power supply. Should an accident occur during the two hours of this enforcement
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discretion, we would be able to operate two (with offsite power) or one (with no offsite power)
CRHVAC unit. One CRHVAC unit is capable of maintaining the Control Room within its design basis. Therefore, this enforcement discretion has no safety significance and de.s not increase the potential consequences of an accident.
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Mr. T. T. Martin, Administrator August 27,1993 Page 3
, COMPENSATORY ACTIONS In order to reduce the possibility of losing offsite power, we will prohibit work in our switchyard during the period of enforcement discretion.
DURATION OF THE ENFORCEMENT DISCRETION We request that a one-time enforcement discretion be granted for two hours and be available for our use until Tuesday, August 31 at 05:15 a.m. If the No.11 CRHVAC is not returned to service by that time, TS 3.0.3 requires that shutdown of both units begin within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.
The two hout duration for the Unit 1 enforcement discretion is based on the two hour action time in Unit 2 TS 3.0.5 which will be applied in parallel.
DETERMINATION OF SIGNIFICANT IIAZARDS ne proposed enforcement discretion has been evaluated against the standards in 10 CFR 50.92 and has been determined to not involve a significaat hazards consideration, in that operation of the facility in accordance with the proposed enforcement discretion:
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Would not involw a significant increase in the probability or consequences of an accident previously evaluated.
He air conditioning units of the Control Room emergency ventilation system provide cooling for recirculated Control Room air and protects the operators from exposure to hazardous airborne materials, ne proposed enforcement discretion will allow Unit I to operate for up to two hours with no operable Control Room air conditioning units.
The Control Room emergency ventilation system is not a precursor to any accident. Failure of the Control Room emergency ventilation system could increase the consequences of an accident by interfering with the operation of the equipment or personnel in the Control Room.
However, even though the Control Room emergency ventilation system will technically be inoperable, air conditioning unit No.11 is functional but has not completed post-maintenance
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testing and the No.12 unit is functional but will not have an emergency power supply.
Herefore, one or both of the units could be brought into service in the event of accident and there would be no increase in consequences.
Therefore, the proposed enforcement discretion does not involve a significant increase in the probability or consequences of an accident previously evaluated.
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Would not create the possibility of a 'new or dferent type of accident from any accident previously evaluated.
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ne Control Room emergency ventilation system is not a precursor to any accident.
Herefore, the proposed enforcement discretion does not create the possibility of a new or different type of accident from any accident previously evaluated.
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. Mr. T. T. Martin, Administrator August 27,1993 3
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Would not inwht a significant reduction in a margin of safety.
The margin of safety supplied by the Control Room emergency ventilation system is the amount of cooling and filtration provided by the system. He filtration of the system is unaffected by this temporary condition. De required cooling could still be supplied in the event of an accident by the functional air handling units even though the units cannot be considered operable according to the technical specifications. Therefore, the proposed enforcement discretion does not involve a significant reduction in a margin of safety.
ENVIRONMENTAL CONSEOUENCES The granting of the requested enforcement discretion will not result in the release of any radioactive or chemical materials to the environment.
Neither will the granting of the requested enforcement discretion change the operation of or limitations on radioactive or chemical waste processing systems.
Therefore, the granting of the requested enforcement discretion has no environmental consequences.
SAFETY COMMITTEE REVIEW This request for enforcement discretion from TS 3.7.6.1 and our discussion of significant hazards considerations have been reviewed by our Plant Operations and Safety Review Committee. They concur that utilization of this enforcement discretion will not result in an undue risk to the health and safety of the public.
Should you have any further questions regarding this matter, we will be pleased to discuss them with you.
Very truly yours,
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d'/4 RED /BDM/bdm/bjd
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Document Control Desk, NRC D. A. Brune, Esquire qg Cvvm J. E. Silberg, Esquire R. A. Capra, NRC D. G. Mcdonald, Jr., NRC P. R. Wilson, NRC R. I. McLean, DNR J. H. Walter, PSC 1
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