ML20028C849
| ML20028C849 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 01/06/1983 |
| From: | Musolf D NORTHERN STATES POWER CO. |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.B.1, TASK-TM NUDOCS 8301140219 | |
| Download: ML20028C849 (1) | |
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0-Northem States Power Company 414 Ncciet Mad MinneapoEs, Minnesota 55401 Telephone (612) 330-5500 January 6, 1983 Director Office of Nuclear Reactor Regulation U S Nuclear Regulatory Commission Washington, DC 20555 PRAIRIE ISLAND NUCLEAR GENERATING PLANT Docket Nos. 50-282 License Nos. DPR-42 50-306 DPR-60 Clarification of Information in Letter Submitted on July 6,1981 Regarding Response to TMI Action Plan Item II.B.1 An ambiguous statement contained in the July 6, 1981 letter was brought to our attention. A copy of the affected page originally transmitted to imR is attached. The last paragraph should read as follows:
"The power supply for the solenoid valves is from the station DC safeguards power, which are the batteries train A & B.
The batteries are maintained fully charged by the battery chargers, powered by AC from the safe-guards buses. The parallel valves, powered off separate battery sources, are provided at both vent sources to assure a vent path exists in the event of a single failure of either a valve or a power source."
Please contact us if you have any questions related to the information we have supplied.
b David Musolf Manager - Nuclear S t Services l
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i cc: Regional Administrator-III, NRC NRR Project Manager, NRC NRC Resident Inspector G Charnoff Attachment 8301140229 830106 DR ADOCK 05000282 PDR
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.s Northem States Powe 414 Necodet Ma8 Mmneapons. Minnesota 58 TeNonone 1812) 330-55C0 1
July 6, 1981 1
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Director of Nuclear Reactor Regulation US Nuclear Regulatory Commission Washington, DC 20555 PRAIRIE ISLAND NUCLEAR GENERATING PLANT Dockec Nos. 50-282 License Nos. DPR-42 50-306 DPR-60 Information Submitted in Response to TMI Action Plan Items II.B.1 and II.D.1 The following is submitted in response to the documentation requirements of NUREG-0737, items II.B.1 and II.D.1:
NUREG-0737, Item II.B.1, Reactor Coolant System Vents The reactor coolant system vent system consists of six remotely operated solenoid valves which can vent either the reactor head or pressurizer steam space to one of two locations, the pressurizer relief tank (PRT) or directly to the containment environment. The normal flow path during fill and vent operations vill be from the reactor & pressurizar to the PRT. The flow path to the containment environment is provided so that large amounts of noncondensibles (such as hydrogen) can be released from the RCS and freely mix with. the containment muasphere. This would keep the hydrogen gas concentratica in containment diluted alow the combustible limit. Good mixing with the containment will also preclude the gas frota collecting in pockets.
The six solenoid valves are located in the containment building on the main operating floor at the 755' level. This loccion was selected for ease of access and to keep new piping runs as short as possible. The valves are a Target Rock one-inch, pilot operated solenoid valve, Model 80B-001. The valves are a fail-closed design with an energize to open scheme. All the system piping is one inch, sch.160, type 304 stainless steel and both RCS system cie-ins are orificed to reduce the vent flow to less than the capacity of one charging pump.
The power supply for the solenoid valves is from station DC safeguards power. Normal supply is from two inverters (train A and train B) which convert 480 VAC to 125 VDC for the valves. During a loss of AC incident the inverters switch to the station batteries for power giving the valves an emergency power source. Parallel valves powered off alternate power source 2 are provided j
at both vent sources to assure a vent path exists in the event of a single i
failure of either a valve or a power source.
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