ML20148C798
| ML20148C798 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 05/23/1997 |
| From: | Dennis Morey SOUTHERN NUCLEAR OPERATING CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-96-06, GL-96-6, NUDOCS 9705290098 | |
| Download: ML20148C798 (7) | |
Text
.
~ -
Dave Mir:y Southern Nucl:ar Vice President Op: rating CompaIy Farley Project P.O. Box 1295 Birmingham. Aiabama 35201 Tel 205.992.5131 SOUTHERN May 23, 1997 COMPANY Enery eo Serve YourWorld" Docket Nos.: 50-348 10 CFR 50.4 1
50-364 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 -
Joseph M. Farley Nuclear Plant Follow-Up Response to Generic Letter 96-06 Open Items Ladies and Gentlemen:
J On September 30,1996, the Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 96-06, " Assurance of Equipment Operability and Containment Integrity During Design-Basis Accident Conditions." The GL required a 30-day initial response and requested a written summary report within 120 days.
i Southern Nuclear provided a 30-day response dated October 24,1996. The 120-day response
]
was provided on January 27,1997. As part of the 120-day response, SNC concluded the l-conditions and/or scenarios discussed in GL p606 are not a significant safety concern at Farley i
l Nuclear Plant. All penetrations determined to be potentially susceptible to thermally-induced j
overpressurization were sufficiently reviewed and an adequate near-term basis for acceptability l
was established. Four (4) penetrations per unit were identified as requiring additional long-term corrective actions.
In the 120-day response, SNC stated all planning associated with the long-term corrective actions for the 4 penetrations per unit would be coalpleted by June 30,1997. Further, any modifications associated with these long-term plans would be implemented prior to startup from the Fall 1998 refueling outage for Unit I and from the Spring 1998 outage for Unit 2.
Subsequent to the above response, SNC was requested to complete the planning for the long-term corrective actions for the affected penetrations by May 30,1997. SNC has completed the i
planning phase for the corrective actions and has enclosed a description of the actions to be
~
completed for the four affected penetrations per unit.
(
pO& b 280000 llll$llllll0lllllllllfl lllll 9705290098 970523 FJR ADOCK 05000340
..e c
P PDR
l U.S. Nuclear Regulatory Commission Page 2 If you have any questions, please advise.
1 Respectfully submitted, SOUTHERN NUCLEAR OPERATING COMPANY bl MeV Dave Morey Sworn to andsubscribed fore me this o?b day af Y0.U I997 N&L b S0W 0
Notary Public (/
My Commission Expires:
8kie do /, / kh 7 L
EFB/ cit:9606FU. doc
Enclosures:
- 1. Long-Term Corrective Actions for Thermally-Induced Penetration Overpressurization cc: Mr. L. A. Reyes, Region II Administrator Mr. J. I. Zimmerman, NRR Project Manager Mr. T. M. Ross, Plant Sr. Resident Inspector Dr. D. E. Williamson, State Department of Public Health 1
l l
l
l I
l ENCLOSURE 1 j
\\
l i
Long-Term Actions For Thermally-Induced Penetration Overpressurization I
i l
l l
i a
t
Long-Term Actions For Thermally-Induced
- ~
Penetration Overpressurization Reauested Information As provided in the 120-day response to GL 96-06 and amplified by subsequent communication between SNC and the NRC, SNC committed to complete the planning for actions to ensure long-term acceptability of four penetrations per unit at Farley Nuclear Plant by May 30,1997.
Any identified modifications for the affected penetrations will be implemented prior to startup from the Fall 1998 refueling outage for Unit 1 and from the Spring 1998 outage for Unit :2.
Below is a summary of the actions planned for each of these penetrations.
SNC Response In completing the review and near-term evaluation for thermally-induced overpressurization of containment penetrations at Farley Nuclear Plant, four penetrations per unit were identified as requiring additional long-term considerations. These penetrations were:
- Reactor Coolant Drain Tank Drain (1/ unit)
- Pressurizer Relief Tank Makeup (1/ unit)
- Refueling Cavity Supply (1/ unit)
- Demineralized Water (1/ unit)
Included below are the near-term acceptability bases provided for the above penetration and the planned corrective actions for long-term acceptability.
Reactor Coolant Drain Tank Drain (Penetration 31)
These penetrations include diaphragm-type valves. Penetrations configured with exposed valves of this design are passively protected from thermally-induced overpressurization.
Because the outside containment isolation valve is of a soft-sea. design, pressurization of L
the piping between the outside containment valve and the inside containment valves would lead to leakage past the seat before the pressure increased to a point where penetration piping would be damaged. The discharge of the inboard valve is directed to the Reactor l
Coolant Drain Tank and the outboard valve is directed to the Waste Processing piping system which are of a large enough volume that the addition of the small amount of water leaking past the soft seat would have no adverse effect.
A review of recent leak rate testing data for the outboard diaphragm valves showed these valves are not leak tight and consistently provide some leakage, thereby relieving the penetration to an open system.
i El-1
Long-Term Actions For Thermally-Induced Penetration Overpressurization l
Therefore, containment integrity would be maintained, and there would be no adverse i
impact to the function of any safety-related component as a result of this pressurization event.
Corrective Action Short Term j
' None required Long Term Modify Penetration 31 to install a relief valve between the containment isolation l
valves. The modifications will be implemented in the Fall 1998 for Unit I and i
the Spring 1998 for Unit 2.
l l
Pressurizer Relief Tank Makeup (Penetration 30) l These penetrations include an outboard diaphragm-type valve and an inboard check valve.'
Diaphragm valves are located downstream of the inboard containment isolation check l
valves which are outside the penetration boundary. Due to the amount of piping between l
the check valves and the diaphragm valves inside containment exposed to an accident l
environment being much larger than the piping between the check valves and the outside containment isolation diaphragm valves, the section of piping outside the pressure boundary would experience a greater pressure rise. Consequently, the diaphragm valves inside containment, but outside the pressure boundary, would be the weak link in this configuration. Leakage by the diaphragm will create a relief path to an open system.
Therefore, containment integrity would be maintained, and there would be no adverse impact to the function of any safety-related component as a result of this pressurization event.
l l
l i
i i
l El-2 4
~
Long-Term Actions For Thermally-Induced Penetration Overpressurization Corrective Action Short Term None required Long Term Modify Penetration 30 to install a relief valve. The modifications will be implemented in the Fall 1998 for Unit I and the Spring 1998 for Unit 2.
l l
Refueling Cavity Supply (Penetration 95) 1 These penetrations include an outboard diaphragm-type valve and an inboard check valve.
l Diaphragm valves are located downstream of the inboard contaimnent isolation check l
valves which are outside the penetration boundary. Due to the amount of piping between the check valves and the diaphragm valves inside containment exposed to an accident environment being much larger than the piping between the check valves and the outside containment isolation diaphragm valves, the section of piping outside the pressure boundary would experience a greater pressure rise. Consequently, the diaphragm valves inside containment, but outside the pressure boundary, would be the weak link in this
- onfiguration. Leakage by the diaphragm will create a relief path to an open system.
Therefore, containment integrity would be maintained, and there would be no adverse impact to the function of any safety-related component as a result of this pressurization event.
Corrective Action Short Term i
None required Long Term The Spent Fuel Pool Cooling valve alignment checklist for both units has been revised to maintain the manual diaphragm valve downstream of the inboard containment isolation check valve in the normally open position. Maintairdng this valve open will provide a relief volume downstream of the check valve inside containment.
i El-3
l l-Long-Term Actions For Thermally-Induced j
Penetration Overpressurization l
l Demineralized Water (Penetration 82)
The Demineralized Water penetration is configured with an outside containment air-operated, globe valve and an inside containment check valve for isolation. During normal l
operation, this penetration is isolated. - Further, the normal system alignment requires the closure of a manual globe valve downstream of the inside containment check valve. The closure of the manual globe valve effectively isolates the associated penetration piping from any appreciable volume that could be used for expansion of the fluid.
Therefore, this penetration is considered susceptible to thermal induced overpressurization.
Corrective Action Short Term To preclude concerns associated with this penetration, plant procedures have been revised to ensure this penetration is drained during normal operation.
Long Term Demineralized Water System operating Procedures (SOPS) will be revised to l
maintain penetration 82 in the drained condition during operating Modes I through 4.
Conclusion By performing the corrective actions identified above, containment integrity will be ensured, and there would be no adverse impact to the function of any safety-related component.
l 8
El-4
,