L-80-179, Forwards Response to IE Bulletin 80-12.Failure of Any Single Active Component During Decay Heat Removal Sys Operation Will Not Result in Loss of Cooling
| ML17208A742 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 06/11/1980 |
| From: | Robert E. Uhrig FLORIDA POWER & LIGHT CO. |
| To: | James O'Reilly, Orielly J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| IEB-80-12, L-80-179, NUDOCS 8006250294 | |
| Download: ML17208A742 (7) | |
Text
P.o. BOX S29100, MIAMI,FL 331S USNBO REGI.":"~..
ATLANTA."LI.'" C. "~il OOJlJNI3 All: 0
. ~',.;--'C L
FLORIDA POWER 8 LIGHT COMPAN June 11, 1980 L-80-179 Mr. James P. O'Reilly, Director, Region II Office of Inspection and Enforcement U.
S. Nuclear Regulatory Commission 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303
Dear Mr. O'Reilly:
Re:
RI I: JPO 50-335 IE BULLETIN 80-12 Florida Power
& Light Company has reviewed the subject bulletin and our response is attached.
Very truly yours, Robert E. Uhrig Vice President Advanced Systems
& Technology REU/NAS/cph Attachment cc:
Director, Office of Inspection and Enforcement Harold F. Reis, Esquire omrcau. aors%
PEOPLE... SERVING PEOPLf
II f(
ATTACHMENT
RESPONSE
TO IE BULLETIN 80-12 P
E\\
1.
The circumstances and sequence of events at Davis-Besse were reviewed.
2.
FPL has reviewed our operating experience and found only a single event that has caused a loss of Decay Heat Removal (DHR).
This event was described in LER 335-78-41 transmitted to the NRC office in Atlanta on November 17, 1978.
Although the result of this incident was the same as the Davis-Besse incident, i.e., loss of DHR; the causes were unrelated.
St. Lucie Unit 1 has experienced no loss of DHR similar to the Davis-Besse occurrence.
3.
5.
The failure of any single active ccmponent during DHR operation will not result in a loss of cooling capability.
Sufficient isolation capabilities, interconnections and redundancy of components are provided to ensure adequate reactor core cooling.
The reactor coolant system can be maintained at refueling temperature using one low pressure safety injection pump and one shutdown heat exchanger.
Backup sources of core cooling water are maintained in the refueling water tank or in the refueling cavity.
These water sources are available on an emergency basis to cool the reactor core in the unlikely event that the entire DHR system is not available-In addition to these
- sources, the Plant Technical Specification 3.1.2.7 requires that a boric acid makeup tank with 1660 gallons of 8 w/o borated water be maintained when the refueling water tank has less than 125,000 gallons.
This borated water source can be mixed with primary water and added to the reactor coolant system through the charging pumps.
A loss of off-site power would not effect the DHR system other than delay the flow of coolant for less than thirty (30) seconds until the onsite power system can pick up the load.
In the above referenced LER, the normal DHR flow path was reestablished without utilizing any backup source of cooling water.
The use of pipe dams in the steam generator primary nozzles will be utilized in the future whenever the steam generator primary manways are removed for extended periods of time.
Installation of these pipe dams will provide the ability to completely refill the DHR suction lines in the event that a
similar loss of inventory occurs and thus improve the ability to restore normal DHR flow quickly.
Technical Specifications at present do not require redundancy or diversity of shutdown cooli ng capability.
Neither do operating nor administrative procedures require such capability.
It has,
- however, always been our philosophy of operation at St. Lucie that the maximum degree of redundancy, consistent with maintenance requirements, be maintained in any mode of operation.
When maintenance must be performed on any safety system the job is worked continuously until the equipment is operable.
We do have an Off-normal Operating Procedure for the SDC/LPSI system.
We will upgrade this and other procedures to reflect the concerns mentioned in this bulletin.
6.
a) iJe intend to develop administrative controls to assure that redundant or diverse DHR systems are available in all modes of operation.
These controls will be implemented by changes to administrative and operating procedures.
Particularly those concerned with operation in modes 5 and 6.
b)
Me will implement controls and changes as necessary to address alternate DHR capabilities or rapid restoration of the lost train.
7.
a)
The controls and procedure changes necessary to address the redundancy and diversity requirements brought out in this ISE report will be ccmpleted by August 1, 1980.
Even more emphasis will be placed on careful maintenance planning to avoid unnecessary or prolonged outages of DHR systems or alternative sources of DHR capabilities.
It should be noted that no DHR maintenance (other than restoring failed equipment) is performed whenever the steam generator manways are open and/or the RCS is drained.
b)
St. Lucie Unit 1 design provides sufficient isolation capabilities, interconnections and redundancy of components to preclude a loss of DHR cooling following the failure of any single active component.
The DHR pumps are powered from independent power sources.
Backup supplies of cooling water are maintained in the refueling water tank, refueling cavity and/or boric acid makeup tank in combination with primary water.
During normal DHR cooling operation, the DHR system is isolated from the containment sump by a manually closed isolation valve and a motor operated isolation valve.
The manually closed isolation valve prevents an inadvertent lineup of the DHR pumps to the containment sump if a recirculation signal is present.
Based on this design, the present DHR system provides adequate assurance against any DHR degradation event.
'k i
STATE OF FLORIDA
)
)
COUNTY OF DADE
)
~
E. A. Adomat being first duly sworn, deposes and says:
That he is Executive Vice President Light Comoany, the scensee herein; of Florida Power That he has executed the foregoing document; that. the state-ments made in this said document are tru and correct to the best of his knowledge, information, and bel'ef, and that he is authorized to execute the document on behalf o
said E. A. Adomat "Subscr-'bed and sworn to before me this
(/
day of NOTARY PUBLIC, 'n and for the County of Dade, State of Florida Nota~ Public, State of Fhrlda at Large My Commission Expires October 30..1983 My COm:ttiSSiOn ezpireS:
Bonded tbru Maynard Bonding Agency
J