ML19350E942
| ML19350E942 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 06/18/1981 |
| From: | Daltroff S PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8106230679 | |
| Download: ML19350E942 (6) | |
Text
.
PHILADELPHIA ELECTRIC COMPANY.
2301 MARKET STREET P.O. BOX 8699 1881 -1981 PHILADELPHIA. PA 19101 e
a mm mom E
bg nJWT4*2L 8[
swistos L. oAtinor,
\\
June 18, 1981 l/,y 4,
c % d 'i y e 1)
. @m Mr. Darrell G. Eisenhut, Director Division of Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Dear Mr. Eisenhut:
In response to your letter of February 25, 1981, we have reviewed our current plant operations to determine our capability to mitigate a station blackout event and conclude that our current operating procedures are adequate.
We have also reviewed our emergency procedures and training and have considered the items in your letter which are listed below with *our responses, a.
The actions necessary and equipment available to maintain the reactor coolant inventory and heat removal with only DC power available, including consideration of the unavailability of auxiliary systems such as ventilation and component cooling.
Response
Peach Bottom Emergency Procedure E-23 defines the actions to be taken by the operator during a complete loss of AC power on both units.
In addition, this procedure assumes there is a stuck open relief valve on one unit and defines the l
equipment available to maintain the reactor coolant inventory and heat removal with only DC power available.
Included in this procedure is a list of the instruments which would be available to determine plant conditions and the location of each instrument.
II e
8106200 d
' 5I I P
\\
Mr. Darrell G. Eisenhut Page 2 Our analysis shows that the unavailability of ventilation and component cooling will cause peak temperatures of 140*F for the High Pressure Coolant Injection (HPCI) system and 139*F for the Reactor Core Isolation Cooling (RCIC) system.
These temperatures are within the design specifications of the HPCI and RCIC systems.
High drywell temperature will cause errors in some drywell instrumentation, however, this is covered in Procedure E-23 which includes the anticipated magnitude of error readings.
b.
The estimated time available to restore AC power and its basis.
Response
Supplement 1 of the Peach Bottom Final Safety Analysis Report (FSAR) addressed the possibility of a complete loss of offsite power concurrent with failure of all diesel generators.
The FSAR states in part that, "The total loss of AC power could only result from multiple failures within the offsite power system and the standby AC power system.
This event'is considered highly improbable and is not a design requirement for Peach Bottom Units 2 and 3".
However, even assuming this hypothetical situation occurs, the FSAR indicates that, "Either the RCIC or the HPCI can supply adequate makeup water to the vessel; therefore, it is assumed that the operator secures one system to minimize DC power requirements.
If the operator fails to take action, both HPCI and RCIC will be automatically secured on a high water level signal.
It is estimated that water level can be maintained without AC power for at least 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />."
Assuming a complete loss of offsite AC power due to the loss of the grid, it is estimated that offsite power would be restored to Peach Bottom in less than thirty minutes.
Mr. Darrell G. Eisenhut' Page 3 1
4 c.
The actions for restoring offsite AC power in the event of a loss of the grid.
Response
Restoration of offsite AC power in the event of a loss of the grid is the responsibility of the System Operacion Division.
A manual titled " System Restoration Following Complete Shut-down" defines the steps to be taken by the System Operation Load Dispatcher to restore power to all generating stations in the event of a loss of the grid.
Step I of the System Restoration Procedure includes provisions for restoring offsite AC power to Peach Bottom.
It is estimated that restoration of AC power to both the 220 KV and 500 KV startup sources at Peach Bottom would require less than thirty minutes.
d.
The actions for restoring offsite AC power when its loss is due to postulated onsite equipment failures.
Response
Due to the diverse nature of the two startup sources th&t feed Peach Bottom, one from the 220 KV system and one from the 500 KV system,'it is very improbable that an onsite equipment failure could cause the loss of all offsite AC power.
If the failure of onsite equipment made an offsite source unavailable, it is standard operating practice for the operator to isolate the failed piece of equipment and restore the rest of the system to normal.
If initial attempts to restore an offsite AC source were unsuccessful, Peach Bottom Technical Specifications permit continued operation for seven days with a single offsite source so that additional steps could be taken to isolate or repair the failed onsite equipment and return the system to normal.
The actions necessary to restore emergency onsite AC power.
e.
The actions required to restart diesel generators should include consideration of loading sequence and the unavailability of AC power, 1
y
~-
~
e
4 Mr. Darrell G.
Eisenhut Page 4
Response
A new procedure addressing the actions necessary to restore emergency onsite AC power will be developed within the six month time limit established by your letter.
This procedure will include instructions on manually starting the diesels from the Control Room and from a local control panel, if necessary.
f.
Consideration of the availability of emergency lighting, and any actions required to provide such lighting, in equipment areas where operator or maintenance actions may be necessary.
Response
During a complete loss of all AC power, emergency DC lighting is provided in selected areas to facilitate continued plant operation and plant egress.
Areas of particular importance during a complete lose of AC power, su,ch as the Control Room, are provided with amergency DC lighting.
Portable emergency lighting is a' 'ilable for areas without emergency DC power.
Additiond. consideration of the availability of emergency lighting and the actions required to provide such lighting will be included in the new emergency restoration procedure referenced in item e.
g.
Precautions to prevent equipment damage during the return to normal operating conditions following restoration of AC power.
For example, the limitations and operating sequence requirements which must be followed to restart the reactor coolant pumps following an extended loss of seal injection sater should be considered in the recovery procedures.
f
Response
Precautions to prevent equipment damage following restoration of AC power will be included in the new emergency restoration procedure referenced in item e.
e Mr. Darrell G. Eisenhut Page 5 The annual requalification training program should consider the emergency procedures and include simulator exercises involving the postulated loss of all AC power with decay heat removal being accomplished by natural circulation and the steam-driven auxiliary feedwater system for PWR plants, and by the steam-driven RCIC and/or HPCI and the safety-relief valves in BWR plants.
Response
Annual'requalification training presently includes a review of -
all emergency procedures.
The new emergency restoration procedure referenced in item e will be included in this review.
Simulator exercises involving the effect of postulated loss of all AC power on decay heat removal have been incorporated into the annual requalification training for Peach Bottom personnel.
gery truly yours, J,/f n,/.
f 5
COMMONWEALTH OF PENNSYLVANIA :
~
ss.
COUNTY OF PHILADELPHIA S. L. Daltroff, being first duly sworn, deposes and says:
That he is Vice President of Philadelphia Electric Company, the Applicant herein; that he has read the foregoing response. to a Nuclear Regulatory Commission letter on Emergency Procedures and Training for Station Blackout Events and knows the contents thereof; and that the statements and matters set forth therein are true and correct to the best of his knowledge, information and belief.
e7 E
-y L./
/
,K ZL(La,f x
>I l 6 Subscribed and s rn to beforemethiskday of (98l.
n -
/
ota
- Publii, ruzA._ H.BOYE
.c. enna.. anaa. Co.
1pw Excym.an.Ja 1982
, - - _ -. - _..