ML20199A243
| ML20199A243 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 11/07/1997 |
| From: | Terry C, Walker R TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-96-06, GL-96-6, TXX-97240, NUDOCS 9711170112 | |
| Download: ML20199A243 (5) | |
Text
e M'
Log # TXX 97240 lllllll" =
File # 10010 L
2 Ref # 10035 r
GL 96 06 1UELECTRIC' November 7, 1997
- c tam tmy
- Groep b PrnWent U. S. Nuclear Regclatory Commission Attn: Document Control Desk Washington, DC 20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NOS. 50 445 AND 50 446 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION ON GENERIC LETTER 96 06 " ASSURANCE OF EQUIPHENT OPERABILITY AND CONTAINMENT INTEGRITY DURING DESIGN BASIS ACCIDENT CONDITIUNS" REF:
Letter logged TXX 97019, dated January 27, 1997, from C. L. Terry to the NRC J
On October 1. 1996, the NRC issued Generic Letter 96 06. " Assurance of Equipment Operability and Containment Integrity during Design Basis Accident Conditions." TV Electric provided the final response to the NRC request in the referenced letter.
In that response. TV Electric identified 4 (four) actions to address Generic Letter 96 06. Attached are tne status of the actions and schedule for completion of the remaining actions for the subject Generic Letter. The actions taken by TU Electric ensures the plant complies with the current licensing basis, therefore, analysis was not used to justify conditions outside of the licensing basis.
Per phone conversation with the NRC on November 6. 1997, fabrication drawings are therefore not needed to comply with this request.
If you have any questions regarding the attached information, please contact Mr. J. D. Seawright at (254) 897 0140.
t ynk 9711170112 971107 PDR A00CK 05000445 P
PDR hh R O. Box 1002 01cn Rme Teus 7604) a
.Pagd 2 of 2
-T!iis commun1' cation contains updated commitments regarding CPSES Units l'and
'2 as identified in Attachment 2.
-Sincerely,
$< $o C. L. Terry By:
~
Roger D... 1ker.
Regulatory Affairs Manager JDS/jds Attachments c-Mr. E. W. Herschoff. Region IV Mr. T. J. Polich NRR Mr. J. I. Tapia, : legion IV Resident Inspector, CPSES L
r..
. to TXX 97240 Page 1 of 2 Action:
Emergency procedures will be revised to require an evaluation by the Technical Support Ce ter engineering team prior to reestablishing chilled water to containment for post accident conditions.
No additional action beyond that identified above is required.
3 Status:
E0P 4).0, Attachment 9. " Post Event System Realignment," has been revised to add a note to ensure that prior to aligning ventilation chilleo water to containment, the plant staff should be contacted to evaluate the integrity of piping inside containment.
Action:
A design change will be issued to lock o)en the manual isolation valves of the component cooling water loop to two leat exchangers in containment to ensure a relief path is available in Modes 1 through 4.
Status:
Design change documents have been issued. The design change will be implemented for Unit 2 during the current refueling outage for Unit 2.
Unit 1 valves will be locked open during the next refueling outage for Unit 1 (spring 1998).
FSAR Figure 9.2 3 (H1 0231 for Unit 1 and H2 0231 A for Unit 2) show the penetrations, the relief valves and the intervening manual isolation valves, Locking open the marual valves is consistent with other penetration thermal relief configurations in the FSAR such as 10S 0105 (FSAR Figure 9.3 10, H1 0253 A, at E 3) and ICS 0106 (FSAR Figure 9.3 10.
H1 0253, at E 1).
Action:
Four relief valves are available to protect the component cooling water return from the Reactor Coolant Pump Thermal Barriers. An automatic isolation valve is located between the penetration and each relief valve.
Each isolation valve receives a close signal on high temperature in the cooling water return lines from each pump.
Because the lines are insulated and the containment temperature drops below the setpoint in less than 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, it is not likely that the fluid temperature would exceed the setpoint.
Although overpressure to the point of failure is unlikely based on conservatisms in the design, containment integrity would not be lost if it occurred. The thermal expansion /over pressure scenario assumes the Component Cooling Water (CCW) piping to be intact and leak tight even though it is not required to be for containment isolation.
A failure or increased leakage due to the pressure increase would not result in a containment breach.
Therefore. the CCW piping barrier is found to be operable, however. TU Electric is continuing to evaluate the design regarding this condition and anticipates design changes to address the effect of thermal expansion on the CCW piping.
I j
o LAttachment I to TXX 97240 Page 2 of 2 r.
' Status:
Analysis shows that power to the autonatic, motor operated isolation valves is tripped at the 480 volt switchgear by the safety injection signal. Two of the valves are-Train A powered and '.wo are Train-B powered ensuring-any-single failure will not cause or allcw the isolation'of all relief valves.
Therefore, automatic isolation will net occur and no design modifications are required.
FSAR Figure 9.2 3 (M1 0231 and M1 0231 A for Unit 1 and H2-operated isolation valves. penetrations, the relief valves and the motor-0231 for Unit 2) shows the The trip for Unit 1 Train A power to MCC IEB1 2 is shown on FSAR Figure 8.3 0, Sh. 1 C 2. The trip for Unit 1 Train B power to MCC IEB2 2 is shown on FSAR Figure 8.3 8, Sh. 2 C 2. Unit 2 power -is tripped similarly.
Action:
ie The Un.it 1 personnel airlock hydraulic system penetrates the containment boundary and has been classified as a closed system inside containment.
The system is isolated by locked closed manual valves outside containment when the airlock is not in use. This isolates the relief valve and lines trapping the hydraulic fluid in the closed system.
An analysis of thermal expansion overpressure -is in progress and has not been completed.
Operability has been evaluated.
If the pressure increased significantly due to thermal expansion, the system contains mechanical seals which would begin to leak and relieve the pressure. A failure or increased leakage due to the pressure increase would not result in a containment breach.
Therefore, the isolation barrier is found to be operable, however, TU Electric is continuing to evaluate the design regarding this condition and anticipates design changes to address the effect of thermal expansion on the hydraulic system.
Status:
Design change documentation has been initiated to add thermal overpressure protection to the Unit 1 personnel airlock hydraulic system.
-Implementation of this design change is planned for the next refueliag outage of Unit 1 (spring 1998).
}
y.
a+ <
.[
t.to TXX 97240 Page l'of 1 COMMITMENTS i
1.
Emergency procedures will be revis,ed to require an evaluation by the Technical Support Center engineering team prior to reestablishing chilled water to containment for post accident conditions.
E0P 0.0L Attachment _9, ' Post Event System' Realignment." has been revised to add a note to ensure-that prior to aligning ventilation chilled water to containment, the plant staff should be contected-to evaluate the
-integrity of piping _inside containment.
j 2.
A design change _ will b3 issued to lock open the manual isolation valves of the component cooling water. loop to two heat exchangers in containment to ensure a relief path is available in Modes i through
- 4. -Design change documents have been issued. The design change dll be implemented for Unit 2 during the current refueling outage for Unit 2. ' Unit i valves will be locked open during the next refueling outage for Unit 1 (spring 1998).
3.
TV Electric is continuing to-evaluate the design regarding this condition and anticipates design changes to address the effect of thermal expansion on the hydraulic system. Design change documentation has been initiated to add thermal overpressure protection to the Unit 1 personnel airlock hydraulic system.
Implementation of this design change is planned for the next refueling outage of Unit 1 (spring 1998).
t t
w
.-.