ML19318B940
| ML19318B940 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 06/09/1980 |
| From: | Gore J BALTIMORE GAS & ELECTRIC CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-80-12, NUDOCS 8006300313 | |
| Download: ML19318B940 (5) | |
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BALTIMORE j
GAS AND ELECTRIC CHARLES CENTER. P.O. BOX 1475 BALTIMORE, MARYLAND 21203 JoMN W. Gong, Jm.
Vict PatsiogNT cocernic surcacom.actio~
June 9, 1980 ANO oatmatioNS U. S. Nuclear Regulatory Commission Docket Nos.
50-317 Division of Inspection & Enforcement 50-318 Region I License Nos. DPR-53 631 Park Avenue DPR-69 King of Prussia, PA 19406 Attention:
Mr. Boyce H. Grier, Director Gentlemen:
IE Bulletin No. 80-12 concerns " Decay Heat Removal System Oper-ability".
Enclosure (1) to this letter responds to the items addressed in this Bulletin pertaining to Calvert Cliffs Units 1 & 2.
Should you have any questions regarding this reply, we will be pleased to discuss them with you.
BALTIMORE GAS AND ELECTRIC COMPANY By:
J.(y/ Gore, Jr. U Vice President-Electric Interconnection and Operations STATE OF MARYLAND:
- TO WIT:
CITY OF BALTIMORE:
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Mr. J. W. Gore, Jr. being duly sworn, states that he is Vice President of the Baltimore Gas and Electric Company, a corporation of the l
State of Maryland; that he executed the foregoing response for the purposes
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... U. S. Nuclear Regulctcry Commissica - 2 June 9, 1980 therein set forth; that the statements made in said response are true and correct to the best of his knowledge, information and belief; and that he was authorized to execute the response on behalf of said corporation.
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. L tMt% ui WITNESS my hand and Notarial Seal:
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My Conunission Expires:
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J. A. Biddison, Esquire G. F. Trowbridge, Esquire E. L. Conner, Jr., NRC R. Sanacore, American Nuclear Insurers Director, Division of Reactor Operations Inspection Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, D. C.
20555
ENCLOSURE 1 ACTIOQ:
Review tne circumstances and sequence of events at Davis-Besse as de-cribed in Attachment 1.
RESPONSE
The circumstances cnd sequence of events leading to the loss of shut-down cooling at Davis-Besse have been reviewed and compared to the Calvert Cliffs design. Since the Calvert Cliffs shutdown cooling
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system differs in several ~ areas with the Davis-Besse design, it has been concluded that the scenario of the Davis Besse incident which resulted in a loss of shutdown cooling would not cause a loss of shutdown cooling with air binding of the system at Calvert Cliffs.
ACTION:
Review your facility (ies) for all DHR degradation events experienced, especially for events similar to the Davis-Besse incident.
RESP 0i1SE:
LER's 77-9,'77-15, 77-17, 77-19, 78-4, 79-15 and 80-11 for Unit one and 78-33, 78-35, and 79-38 for Unit two describe all events whicn resulted in degradation of snutdown cooling at Calvert Cliffs. The event descriptions, cause descriptions and corrective actions to pre-vent recurrence were reviewed to insure that the corrective action taken in each event was adequate to reduce the probability of a re-currence.
It was determined that in eacn event the corrective action was appropriate.
ACTION:
Review the hardware capability of your facility (ies) to prevent DHR loss events, including equipment redundancy, diversity, power source reliability, instrumentation and control reliability, and overall reliability during the refueling and cold shutdown modes of operation.
RESPONSE
Reference should be made to Calvert Cliffs FSAR Chapter 9.2.
Hardware capabilities to prevent degradation of shutdown cotling include:
l 1.
Equipment redundancy-Normal sh,utdown cooling is provided by re-dundant low pressure safety injection purps and redundant shut-down cooling heat exchangers.
The support systems for DHR, com-l I
ENCLOSURE,1(CONT'D) ponent cooling and salt water cooling, each have three pumps and two heat exchangers; 2.
Diversity - The redundant normal shutdown cooling system and the redundant steam generator /feeddater systems discharging heat via either the atmospheric dump valves or the turbine by-pass valves provide diversity of decay heat removal capabilities.
Further diversity is provided by the spent fuel pool cooling system which becomes available once the refueling pool is filled and the RV head has been removed.
3.
Power source reliability - The pumps in the normal shutdown cooling system have redundant and independent power sources which are auto-matically powered by the diesel generator in the event that the nor-mal power is lost; and, 4.
Instrumentation and control reliability - Loss of shutdown cooling is indicated by redundant flow, pressure, and temperature indicators on both the reactor coolant system side and the support systems (component cooling and salt water cooling) sides-of the shutdown cooling system.
Indication and controls are provided in the main control room to allow the operator to take the necessary actions to provide one of the alternate means for shutdown cooling in the event that nonnal shutdown cooling should be lost.-
On loss of air, the pneumatic control valves in the shutdown cooling support systems fail to the open position to allow continued cooling flow.
Loss of air to the shutdown heat exchanger outlet control valve will fail the valve closed.
Position indication lights in the control rooms advise the operator of the valve's position, and a handwheel on the valve allows manual operation.
Overall shutdown cooling system reliability during the refueling and shutdown modes is insured by tne redundancy and diversity of cooling modes provided by the normal shutdown cooling system, the steam generator /feedwater system, and tne spent fuel pool ccoling/
containment coolers system and by the redundancy of power supplies for the critical shutdown cooling equipment.
ACTION:
Analyze your procedures for adequacy of safeguarding against loss of redundancy and diversity of DHR capability.
Analyze your procedures for adequacy of responding to DHR loss events.
Special emphasis should be placed upon responses when maintenance or refueling activities degrade the DHR' capability.
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ENCLOSURE 1 (CONT'D)
Until further notice or until Tachnical Specifications are revised to
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resolve the issues of this Bulletin, you should:
a.
Implement as soon as practicable administrative controls to assure tnat redundant or diverse DHR methods are avail-able during all modes of plant operation.
(Note: When in j
a refueling mode with water in the refueling cavity and the head removed, an acceptable means could include one DHR train and a raadily accessible source of borated water to replenish any loss of inventory that might occur subsequent to the loss of the available DHR train).
b.
Implement administrative controls as soon as practicable, for those cases where single failures or other actions can result in only one DHR train being available, requiring an alternate means of DHR or expediting the restoration of the lost train or method.
Report to the NRC within 30 days of the date of this bulletin the results.
of the above reviews and analyses, describing:
a.
Change to procedures (e.g., emergency, operational, adminis--
trative, maintenance, refueling) made or initiated as a re-sult of your reviews and analyses, including the scheduled or actual dates of accomplishment; (Note: HRC suggest that you ' consider the following:
(1) limiting maintenance activ-ities to assure redundancy or diversity and integrity of DHR capability, and (2) bypassing or disabling, where applicaole, automatic actuation of ECCS recirculation in addition to dis-abling Hign Pressure Injection and Containment Spray prepara-tory to the cold shutdown or refuel.ing mode)..
b.
The safeguards at your facility (ies) against DHR degradation, including your assessment of their adequacy.
RESPONSE
Procedures and administrative controls relating to the operation of the shutdown cooling system have been reviewed for adequacy to assure that redundant er diverse methods of decay heat removal are available. As a result of the above review a Nuclear Plant Engineer-0perations stand-ing instruction has been issued to require redundant or diverse modes of decay heat removal capability whenever the snutdown cooling system is required for operation.
Technical Specifications address operability requirements-for heat removal equipment during all other modes of plant operation.
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