ML19305D324
| ML19305D324 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/03/1980 |
| From: | Herbein J METROPOLITAN EDISON CO. |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| TLL-157, NUDOCS 8004140386 | |
| Download: ML19305D324 (3) | |
Text
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i Metropolitan Edison Company Post Office Box 480
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Middletown, Pennsylvania 17057 717 944-4041 Writer's Direct Dial Number April 3, 1980 TLL 157 Director of Nuclear Reactor Regulation Attn:
R. W. Reid, Chief Operating Reactors Branch No. 4 U. S. Nuclear Regulatory Commission Washington, D.C.
20555
Dear Sir:
Three Mile Island Nuclear Station, Unit I (TMI-I)
Operating License No. DPR-50 Docket No. 50-289 Purge Valves On March 11,1980 (TLL 113), a letter was sent to your office requesting an extension in response to your letter of January 9, 1980. Later, on March 14, 1980, a conference call was arranged between membars of your staff and consultants and Met-Ed/GPUSC. During this conversation, frequent reference was made to Section 2.1.1.5 of the TMI-I Restart Report which discusses Containment Isolation Modifications. Therefore, enclosed please find our responses to your Questions 2, 3, and 4 of your January 9, 1980 letter. The response to Question 1 will be provided by May 1, 1980.
Sincerely, s
/ - --
J. G. Herbein f.
Vice President Nuclear Operations JGH:LWH: hah cc:
J. T. Collins
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Metropoi tan Ed: son Company is a Mernber of the General Puohc Utsties Systern j
8004140 3 3 6
C.
QUESTION 2:
Your response does not adequately address the following areas. Please discuss how your design conforms with each:
The overriding of one type of safety actuation signal (e.g., radiation) a.
should not cause the blocking of any other type of safety actuation signal (e.g., pressure) to the isolation valves.
b.
Sufficient physical features (e.g., key lock switches) should be provided to f acilitate adequate administrative controls.
The system-level annunciation of the overridden status should be l
c.
provided for every safety system impacted when an override is active.
l d.
Diverse signals should be provided to initiate isolation of the containment ventilation system. Specifically, containment high radiation, safety injection actuation, and containment high pressure should automatically initiate Containment Ventilation Isolation (CVI).
e.
The instrumentation and control systems provided to initiate CVI l
should be designed and qualified as safety-grade equipment.
f.
The overriding or resetting of the isolation actuation signal should not cause the automatic reopening of any isolation / purge valve.
RESPONSE TO QUESTION 2a:
The overriding of any one type of isolation signal (radiation, reactor trips, high building pressure) to the purge valve will not block any of the other signals from performing their isolation function.
I RESPONSE TO QUESTION 2b:
Key operated permissive s'ritches are being installed in each of the purge valve open circuits. It will be necessary for an operator to obtain a key and operate the permissive switch before a purge valve can be opened. Opera-1 tion of a permissive switch will cause an alarm to be initiated in the control room.
RESPONSE TO QUESTION 2c:
See answer to Question 3a below.
RESPONSE TO QUESTION 2d:
Diverse signals are being provided to isolate the purge system. The valves will be automatically closed by safety grade reactor trip or high pressure signals. In addition they will be closed by safety grade high radiation signals.
y RESPONSE TO QUESTION 2e:
See Section 2.1.1.5 of TMI-I Restart Peport.
RESPONSE TO QUESTION 2f:
The ovecriding or resetting of any isolation actuation signal will not cause automatic reopening of any valve.
QUESTION 3:
With regard to your response of January 4,1979 (GQI 0007), please provide the following additional clarification:
a.
The response of January 4,1979 (GQI 0007) indicates that bypassing of the high radiation signals is annunciated in the control room, while bypassing of the high reactor building pressure signals is not.
What is your intent on annunciating the bypass of any CVI actuation signal?
b.
The response states that " bypassing (high radiation actuation signal) does not defeat the ES actuation." Verify that bypass of the ES actuation signal does not bypass high radiation actuation.
RESPONSE TO QUESTION 3a:
The bypassing of high radiation signals is annunciated in the control room since this action could cause blocking of an isolation signal. The high reactor building pressure signal cannot be " bypassed." There is an override i
switch which is only functional af ter high pressure signal is present. This requires no alarm. In addition see answer to Question 2b above. We feel that this design is satisf actory and no change is contemplated.
RESPONSE TO QUESTION 3b:
Detailed drawings of the design will be provided as an amendment to the Restart Report by May 30, 1980.
QUESTION 4:
Describe the manual control circuits and include the schematic diagrams as necessary showing how automatic actuation signals defeat manual "open" command, even af ter removal of the actuation signal.
RESPONSE TO QUESTION 4:
Detailed drawings of the design will be provided as an amendment to the Restart Report by May 30, 1980.
.