ML19290E465
| ML19290E465 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 03/03/1980 |
| From: | Daltroff S PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Ippolito T Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8003110327 | |
| Download: ML19290E465 (3) | |
Text
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6 PHILADELPHI A ELECTRIC COM PANY 2301 MARKET STREET P.O. BOX 8699 PHILADELPHI A. PA.19101 0 "
I swirtos L. D ALTROFF veCs possnosur absCTweC PRODUCTIO88 March 3.
1980 Docket Nos. 50-277 50-278 Mr. Th o ma s A.
Ippolito, Chief Operating Reactors Branch #3 Division of Operating Reactors US Nuclear Regulatory Commission Washington, DC 20555
Dear Mr. Ippolito:
This letter is in response t o y ou r letter to E.
G.
- Bauer, Jr..
dated January 2,
1980, concerning containment purging and venting during normal plant op e ra t i on at Peach Bottom.
Each item of concern is restated f ollowed by our response.
It_e m a.
Discuss the provisions made to ensure that isolation valve closure vill not be prevented by debris which c ou ld potentially become entrained in the escaping air and steam.
.Re s.pp_n s e Design features are currently not provided at Peach Bottom to ensure.that purge and vent valve closure will not be p revent ed by debris which could p otentially become entrained in the escaping air and steam.
While the p robability of encountering dif ficulties due to debris entrainment is quite low, the design requirements for such protective features are cu rre nt ly being developed by the valve manufacturer (Fisher) and ou r Architect-Engineer (Bechtel).
"Q Y s
//O 03110Wd
4 Mr.
T.
A.
Ippolito, Chief Page 2
.I_t _e m b.
Discuss the p rovisions made for testing the availability of the isolation function and the leakage rate of the isolation valves, individually, during reactor operation.
Response
Local leak rate tests of the purge and vent valves are cu r r e n t ly perf ormed du rin g refueling outa3es in accordance with the requirements of 10 CFR 50, Appendix J and the Plant Technical Specifications.
The capability to leak rate test the purge and vent valves during reactor operation cu rrent ly exis s.
Such testing would have to be p erf ormed by pressurizing between the inner and outer valves.
The validity of tes ting the inner valve in its non-accident direction is cu rren t ly being reviewed by the valve manufacturer (Fisher).
Item c.
Provide an an a ly s i s to demonstrate the acceptability of the provisions made to protect structures and safety-related equipment, e.g..
fans. filters and ductwork located beyond-the purge system isolation valves against loss of function from the environment created by the escaping air and s team.
Response
Gases being vented from the Peach Bottom p rimary containment are transported t h rou gh ductwork to the Standby Gas Treatment System (SGTS) for filtration prior to release.
Our Architect-Engineer (B e ch te l) has recently comp le ted an analysis of the pressure surge that the SGTS filters could be e xp os e d t o if a DBA-LOCA were to occur while the vent valves were open.
The pressure differential across the filters is calculated to exceed the dif f erential f or which the filters have been designed if the large diameter (18") vent valves were in an op en position.
As described in our January 2,
1979 letter to the NRC, these valves are opened only for deinerting du ring s hu tdowns, ventilation du rin g ou tages, and inerting du ring s tartups.
The above letter further addresses limitations on the total time that inerting and deinerting may be p erf ormed.
In conjunction with our Architect-Engineer (Bechtel) and several manufacturers, we are cu r ren t ly evaluating methods of preventing filter damage.
4 Mr.
T.
A.
Ippolito, Chief Page 3 It_em d.
For the containment purge isolation valves, specify the dif f erential p res sure across the valve for which the ma xi mu m leak rate occurs.
Provide test results (e.g.,
from vendor tests of leakage rate versus valve dif f erential p res sure) which support y ou r conclusion.
Response
As discussed in b.,
above, the valve manufacturer (Fisher) is cu r rent ly reviewin g the subject of leak rate testing.
This r ep ort will include an assessment of leakage vs. differential pressure.
Our review of the containment purging and venting system is currently in p rogres s.
We anticipate comp le tion of this review by April 30, 1980 for items a,b,d and item e by June 1,
1980.
Sh ould y ou have any questions or require additional i n f o r ma t i*o n, please do not hesitate to contact us.
Very t ru ly y ou rs,
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