ML20096G796
| ML20096G796 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 09/05/1984 |
| From: | Musolf D NORTHERN STATES POWER CO. |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8409110151 | |
| Download: ML20096G796 (1) | |
Text
Northem States Power Company 414 NicoHet Matt Minneapohs. Minnesota 55401 September 5,1984 Tewpnone tsi21330-ssoo Director Office of Nuclear Reactor Regulation U S Nuclear Regulatory Commission Washington, DC 20555 PRAIRIE ISLAND NUCLEAR GENERATING PLAIE Docket Nos. 50-282 License Nos. DPR-42 50-306 DPR-60 Supplement No. I to Description of 'fodifications for Automatic Actutation of Scram Breaker Shunt Trip Attachment In our letter dated July 6,1984 we provided for NRC review a description of the shunt trip actuation design proposed for implementation at the Prairie Island Nuclear Generating Plant. This design has undergone further review and a design improvement has been identified. The purpose of this letter is to describe this improvement.
A switch will be installed on the relay protecton racks in series with the white monitor light, shown in the sketches included in Attachment I to our July 6,1984 submittal. The control room indication of trip circuit readiness depends on the fact that the current through the control board red indicating light goes through the shunt coil and breaker "a" contact. As originally proposed, the new white monitor light at the reactor protection rack is in parallel with the "a"
contact, and could cause a false readiness indication. With the proposed switch in series with the white monitor light, test procedures will allow it to be connected into the breaker circuit only during testing.
No change in the discussion of licensing issues is required due to the change, except that the new monitor light isolation switch should be included in the section 5.1.4 discussion of equipment qualification.
The discussion in this section is applicable to the new switch. The component type anticipated for this switch is a Westinghouse Type OT2 snap ac61on switch.
Please contact us if you have question related to the information we have provided.
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u David Musolf Manager - Nuclear Suppo Services DT!/le k
cc: Regional Administrator-III NRR Project Manager, NRC Resident}nspector, MRC gg G Charno 8409110151 B40905 PDRADOCK05000g P