ML19345E229
| ML19345E229 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 12/16/1980 |
| From: | Daltroff D PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8012230493 | |
| Download: ML19345E229 (2) | |
Text
.
s-,
- /
PHILAD ELPHI A ELECTRIC COM PANY 2301 M ARKET STREET P.O. BOX 8699 PHILADELPHIA. PA.19101 SHIELDS L, D ALTROFF eLECY# C PRO TION December 16, 1980 Re: Docket Nos. 50-277 50-278
'! r. Darrell G.
Eisenhut, Director Division of Licensing U.S.
Nuclear Regulatory Commission Nashington, DC 20555
Dear Mr. Eisenhut:
This letter is in response to your letter dated October 1, 1980, which requests the results of a reevaluation of our scram system with respect to the design and performance criteria developed by the BUR Owners' Group.
This criteria was transmitted to us by General Electric letter PUM-80193 dated October 23, 1980.
Our reevaluation has determined that, while the system is in conformance with most of the criteria outlined by the owners' Group, the following modifications are required to provide complete conformance:
1)
Extend the existing scram discharge volumes (SDV) so they connect directly into the instrument volume.
The new piping will be equal in cross sectional area to that used for the existing SDV's.
This modification will ensure proper drainage.
There will be no dependence on the vent and drain system for the proper detection of water, and additional discharga volume will be provided as added margin for scram.
2)
Provide redundant isolation valves on the SDV system vent gnd drain lines in series with the existing valves.
The valves yould be similar in design and function to the existing valves and would protect against loss of reactor
- r..
I s
B
, J
!! r. Darrell G.
Eisenhut Page 2 coolant fron the discharge volume, given a single active failure of one of the valves.
3)
Remove relief valve RV-34 on the instrument volume drain line, thereby eliminating the potential for release of reactor coolant following failure of this valve.
'J e have determined, in conjunction with General Electric, that this pressure relief function will be accomplished by the existing reactor safety-relief valves.
4)
Reroute the piping for the level detection instrumentation such that it connects directly with the instrument volume and not be interconnected through the vent and drain piping.
In addition to the above modifications required to bring Peach Botton Units 2 & 3 into conformance with the owners' Group criteria, the following modifications, which were discussed in our letter to B.
H. Grier, dated August 29, 1930, will be implenented to improve the reliability and availability of the system:
a)
Provide cross connection piping between the discharge volume vent lines on each unit, upstream of the vent valves, such that a vent path to both headers will be assured, given the failure of a vent valve to re-open on scram reset.
b)
Provide a vent path between the top of the instrument volume and the discharge volume vent system to assure that any air trapped in the system during a scram is at the high point of the system.
The impact of air expansion on the level instrumentation on scran reset is thereby minimized.
i All the above items for Unit 2 are to be completed j
during the next unit refueling (scheduled for the beginning of j
1982).
The modifications on Unit 3 are scheduled for the 1981 1
Spring refueling outage contingent upon the timely receipt of equipment and materials required for the modifications.
l If you have any questions or require additional l
information, do not hesitate to contact us.
Very truly yours, I
//
'/.
\\
z - f:) L~.'
! I i
l
.m