ML20032D988
| ML20032D988 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 11/09/1981 |
| From: | Rausch T COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| NUDOCS 8111190455 | |
| Download: ML20032D988 (3) | |
Text
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D N. Commonwealth Edison'
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O ) One First National Plaza. Chicago.~ lihnois kC J Address Reply to: Post Office Box 767 (j Chicago Illinois 60690 November-9, 1981 Mr. James G. Keppler, Director I./A Directorate of Inspection and~
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Subject:
Dresden Station Units 2 and 3 Actions Taken to Correct CCSW ic Piping Support Damage NRC Docket Nos. 50-237/249 Reference (a):
J. G.
Keppler letter to Cordell Reed dated October 9, 1981.
Dear Mr. Keppler:
On October 23, 1981, a meeting was held at your of fice to discuss the Commonwealth Edison Company actions taken subsequent to the discovery of damaged piping supports on the Dresden Unit 2 Containment Cooling Service Water (CCSW) system.
The following provides information which we committed to supply during this meeting, and also provides the 30-day response to your Reference (a)
Confirmatory Action Letter.
Item 3 of Reference (a) Confirmatory Action Letter (Describe permanent changes to CCSW and schedule for installation).
We have determined that a fill line from the diesel generator cooling water system to the CCSW is the most expedient and cost effective modification.
This modification will require a 1" tap in the diesel generator cooling water line which is reduced to two, 3/4" lines which tap into the CCSW 2A and 2B loops.
Our best estimate is that the design, procurement and installation of this modification for Unit 2 will take approx-imately four months..Any problems we have in obtaining the necessary materials could cause a delay in this schedule.
The following numbers refer to the draft October 23, 1981, meeting agenda items provided by F.
Reiman of your of fice on October 13, 1981.
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8111190455 811109 DRADOCKOSOOg3d NOV.
19 81 p
s
-J.
G. Keppler Novemb'e r. 9, '19 81
~1.
and 2.b.
Schedule for upgrade of CCSW loops 2A, 28, 3A and 3B to meet FSAR-reouirements:
The CCSW 2A loop analysis will' be completed byf Novem' r 30, 1981.
Design, material procurement'and'installatio:
_f any
. hangers will take approximately four to five months after-
' completion of analysis.
The 28 loop analysis has been completed and hanger designs are scheduled to be complete by Janauary, 1982.
Material procurement and installation will take approximately four months.
The CCSW loops 3A and 38 analy3es will be completed on the normal 79-14 schedule which will be submitted in February, 1982, with design and installation following analysis-completion by five months.
Again, these schedules assume that material procurement will not be a problem.
2a.
Schedule for I.E.Bulletin 79-14 requirements:
Commonwealth Edison previously indicated that we would complete analysis of both Dresden and Quad Cities safety-related systems in April, 1982.
However, because of
. reorganization of priorities to analyze the CRD, HPCI and CCSW systems,.this schedule is going to be extended past April.
At tne present time, the eff' t cannot be quanti-fled.
Commonwealth Edison will respond in the February,
- 1982, I.E.Bulletin 79-14 monthly status update with revised
.i schedule information.
j 3.
Address need for protection of the torus for piping or hangers within six inches of the torus shel):
An inspection of the torus was performed to locate any piping or hangers which came within six inches of the torus shell.
The systems found within that six-inch envelope that may be i-susceptible to a water feed are:
4 1.
Low Pressure Coolant Injection (LPCI) 2.
High Pressure Coolant Injection (HPCI) 3.
4.
Reactor Building Closed Cooling Water (RBCCW) 6.
Service Water Our review of these systems fir s o.c are currently susceptible to a water hammer event.
Th 2 a is are as follows:
A.
The LPCI, HPCI and Cort-Sprof.gstems all have a jockey pump to pressure their 10tpective lines and prevent the i
chance for any voids forming.
The Containment Cooling Service Water (CCSW) subs > stem of LPCI will have some form of a " keep fill" system' installed.
L
~
w J. G. Keppler November 9, 1981
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B.
These systems currently have adequate procedures.which preclude the chance'forfwater hammer.
This includes the CCSW system.which has had recent changes made to minimize check valve slam and insure the piping'is slowly filled-with water., Depending on the final modifications,
. additional procedure changes may be necessary.
C.
Many of the systems are low-pressure systems, which reduces the chance of a severe water hammer event.
-In addition to theLsystems already mentioned, we reviewed the procedures for other systems im;'rtant to_ safety to insure that those systems are properly fillet and_ vented.
The only system which has procedures in need of improvement is the Diesel Generator Service Water (DGSW) system.
Here,-a procedure change is currently being prepared.
4.
Evaluation to determine that further damage from hydraulic shocks will not occur:
i CCSW hea' exchanger drain down will no longer occur following the system modification to install a fill line.
In the interim, procedure revisions (which require, among other things, throttling the pump discharge-valves from a partially closed position upon pump start) preclude further hydraulic shock damage.
EDS Nuclear is analyzing the check valve' slamming to determine its. affect on the piping system.
By November 20, 1981, the load _
from this event will be determined; at that time, further evaluation will take place if necessary.
5.
Fatigue evaluation of CCSW loop 2A:
As suggested by the NRC, the load required to pull the three-way restraint out of the wall, will be applied to.the pipe to determine the systems pipe stresses.
This analysis will take
.approximately four months'and.at that time any further evaluation can be scheduled.
'Please address any questions you may have concerning this matter'to this office.
Very truly yours,
%k omas-J. Rausch Nuclear Licensing Administrator Boiling Water Reactors cc:
Region III Inspector - Dresden
- 2844N
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