ML17173A730
| ML17173A730 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities  |
| Issue date: | 03/29/1979 |
| From: | Reed C COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7904100286 | |
| Download: ML17173A730 (4) | |
Text
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Co.onwealth Edison One First National Plaza. Chicago, Illinois Address Reply to: Post Office Box 767 Chicago. Illinois 60690 March 29,. 1979.
Mr. Harold R. Denton, Director Office of Nuclear Reactor.Regulation I
U.S.* Nuclear Regulatory Commission Washington, D.C.
20555
Subject:
References (a) :
Recirculation Pump Trip Modification Dresden Station Units 1, 2 &'3 and Qtiad-Cities Station Units 1 and 2 NRC Docket Nos. 50-10/237/249 and 50-254/265 H. R. Denton letter to C. Reed dated January 8, 1979 (NRC Docket Nos. 50-10/237/249)
(b):
H. R. Denton letter to c. Reed dated January 8, 1979 (NRC Docket Nos. 50-254/265)
Dear Mr. Denton:
This transmittal is in* response to your request in References (a) 'and (b) that a recirculation pump trip (RPT) be instatled on Dresden Units 1, 2 & 3 and Quad-Cities Units 1 and 2.
In consideration of the fact that the appendices t"o the referenced letters identify the final criteria for the RPT.
system and that the NRC intends "to effect no changes to those criteria in the future," Commonwealth Edison reaffirms commit-ments previously made to install-and make operational an RPT system of acceptable design.
The installation schedule for the subject system is delineated below:
'7904100 ~ 8l,
- .-*. -----*-;~*--* --
Commonwealth Edison tc Docket Nos. 50-10/237/249 50-254/265 Mr. Harold R. Denton:
Dresden Unit 1 Dresden Unit 2 Dresden Unit 3 Quad-Cities Unit 1 Quad-Cities Unit 2 2 -
March 29, 1979 Jantiaryl981 Fall 1980 refueling outage Spring 1980 refueling outage Fall 1980 refueling outage Fall 1981 refueling outage In the case of Quad-Cities Unit 2, the next refueling outage is scheduled for the Fall of 1979.
Because equipment deliveries will
-~
require in. excess of 10 months, it is our current judgement that the Quad-Citles Unit 1 modification cannot be initiated sooner than Fall 1981 which is the date for the next scheduled refueling.
- An attempt will be made to expedite equipment deliveries for this unit *. We will advise you in the event circumstances develop which jeopardize the dates provided above since changes in refuel*ing schedules may affect these projected installation dates.
- However,
- it is this utility's intention to install the subject RPT system as soon as practicable within the constraints of equipment delivery and unit availability.
The design of the RPT system to be installed on D*resden Units 1, 2 & 3 and Quad-Cities Units 1 and 2 will be equivalent to that described in References (a) and (b) for the Monticello RPT system.
In the case of Dresden.1 only, two differences will.
exist as a result of differences in the NSSS.
These are:
- 1.
The four D-1 recirculation pumps are single speed direct drive.
The RPT signals will
.. trip the appropriate 4 kV circuit breakers rathei than the field breaker of a motor generator set.
- 2.
The present design of the D~l recirculation pump control system includes a pump trip initiated by low steam drum level.
This feature will be retained as is.
The equipment necessary to provide a reactor high pressure RPT signal will be added.
The modi:f ications to the five units will be reviewed and irnplemented in conformance with the requirements of 10 CFR 50.59.
Commonwea Ith* Edison Docket Nos. 50-10/237/~49 50-254/265 Mr~ Harold R. Dentori:
- 3.-
March 29,
- 1979.*
Thi*s conunitmen:t, to install RPT does not consti.tute.
- agreement with any particular option for resolving ATWS as identified in NUREG-0460, Volume 3.
This utility intends, either singly or in concert with other affected utilities, to take part in the decision process that determines which, if any, of the options identified in NUREG-0460, Volume 3 is adopted for the reactors operated by this utility.
Your January 8, *. 1979 letters also required the* development and implementation of interi.ffi procedures and the training of operators to recognize and respond to an ATWS event.
That training program, which. has now been initiated,*emphasizes prompt recognition of an ATWS.event so that the decision to manually trip the,l?e*c:irculation -pumps can.*be. made as soon as possible and also defines a specific logical sequence of operator actions to insert the control rods.
In addit.ion, the interim procedures. are
- designed to provide the operator with sufficient information so that he know's if. and when he must initiate the standby liquid control system (SBLC) and will not hesitate to proceed. A summary of the content of the program is provided below:
- 1.
Define the ATWS event to all licensed.personnel.
- 2.
Operator training to recognize an ATWS event includes:
(a) scram indicators (b) rod position indicators (c) flux monitors (d) reactor/containment indicators
- 3.
Operator training to take mitigating action without automatic RPT includes:
(a) recognition of an ATWS event (b) manual scram of the reactor (manual scram button)
(c) manual tr.ip of the recirculation pumps (d) manual scram of the reactor by alternate means (e) actuation of the standby liquid control system (f}- manual initiation of RHR system (pool cooling_
mode)
. *-*-*................:...... : ___ :***~.- -* -"':".::'-------*'----*-*
Commonwealth Edison
- NRC Docket Nos. 50-10/237/249-so-254/265 Mr. Harold R.* Denton: March 29, 1979 Both the training progra.m and the interim procedures are designed
- to result in ~onsistent operator action before *and after th~ RPT modification is incorporated.
. In summary, Co:rnmonwealth Edison commits to incorporate a recirculaticm pi.µnp trip of a design identified by the NRC as acceptable~ The implementation of this-modification on Dresden Units 1, 2.& 3 and Quad-Cities Units 1-and 2 will be completed on a schedule consistent.with the guidance provided in References (a) and (b).
Furthermore, interim procedures have been prepared and operator training initiated to provide additional assurance
.t:hat in the extremely unlikely event of an AT1'tlS, appropriate operator 'action will be taken expeditiously.
At Quad-Cities Station the training program. has. been completed.
At Dresden Station, since all three units are currently engaged in outages, the training program for each unit will be completed before the unit is returned to service.
Very truly yours, Cordell Reed Assistant Vice-President