ML18051A594
| ML18051A594 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 09/08/1983 |
| From: | Johnson B CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8309130062 | |
| Download: ML18051A594 (2) | |
Text
consumers Power company General Offices: 1945 West Parnall Road, Jackson, Ml 49201 * (517) 788-0550 September 8, 1983 Dennis M Crutchfield, Chief Operating Reactor Branch No 5 Nuclear Reactor Regulation US Nuclear Regulatory Commission Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT - MAIN STEAM LINE BREAK WITH CONTINUED FEEDWATER ADDITION Consumers Power Company letter dated July 26, 1983 regarding main steam line break (MSLB) with continued feedwater addition contained our commitment to install modifications to the control circuitry of the main feedwater stop valves and the feedwater bypass valves to initiate closure on low steam generator pressure and to add control valves in series with the feedwater bypass valves that also close on steam generator low pressure.
In a telephone call on September 1, 1983 with members of your staff, Consumers Power Company committed to provide additional information regarding the potential consequences of such an event and the compensatory measures that have been taken to cope with the event until the proposed modifications can be completed.
Consumers Power Company letters dated October 26, 1982 and July 26, 1983 evaluated the consequences of such an event and found that the potential exists for exceeding the containment design pressure (55 psig).
Although no analysis has been performed to precisely quantify the peak containment pressure that would result, it is apparent for the reasons listed below that containment pressure would not exceed that predicted for the blowdown of both steam generators, which the NRC staff has concluded is acceptable based on containment design margins for the specific issue of two steam generator blowdown due to main steam line isolation valve failure (ref. NUREG-0820 -
Integrated Plant Safety Assessment - Palisades Plant, October, 1982).
These reasons are:
- 1.
The continued feedwater addition concern is only applicable if offsite power is available.
In that case substantially more contain-ment heat removal equipment (two spray pumps and four air coolers as compared to one spray pump and three air coolers) would be available to limit the peak containment pressure; and 8309130062 830908 PDR ADOCK 05000255 P
PDR OC0983-0004B-NL02
'DMCrutchfield, Chief Palisades Plant MAIN STEAM LINE BREAK W/CONTINUED FEEDWATER ADDITION September 8, 1983
- 2.
The rate of mass and energy release to containment will be substantially less that that for a two steam generator blowdown.
2 Our letter of April 26, 1982 described the capabilities of the main feedwater isolation system as presently designed.
The system consists of isolation valves in each main feed line and bypass line which close automatically on low steam generator pressure.
The possible single failure of a valve to close is addressed in the emergency operating procedures wherein the operator is instructed, as part of his immediate actions, to check the position of the main feedwater regulating and regulating bypass valves to verify that they are in fact closed. If a valve did not close, the operator would attempt to isolate the main feedwater system by manual means including closing the main feedwater regulating and block valves and the main feedwater bypass regulating valve either from the control room or at the valve itself.
Brian D Johnson Staff Licensing Engineer CC Admintstrator, Region III, USNRC NRC Resident Inspector - Palisades OC0983-0004B-NL02