ML20096A289
| ML20096A289 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 05/04/1992 |
| From: | Parker T NORTHERN STATES POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9205110020 | |
| Download: ML20096A289 (1) | |
Text
.__m Northem States Power Company r
414 Nicollet Mall Minneapohs, Minnesota 55401 1927 Telephone (612) 330-5500 May 4, 1992 U S Nuclear Regulatory Comni.sion Attn: Document Control Desk kashington, DC 20555 PRAIRIE ISLAND NUCLEAR GENERATING P1 ANT j
Docket Nos. 50-282 License Nos. DPR-42 l
50 306 DPR-60 Use of a New Fire Retardant Continn for Pirinn Insulation A commit t ent specified in the Prairic Island Fire Protection Program NRC Safety Evaluation Report requires the use of a fire retardant intumescent 1
l coati.ig on all polyurethane foam piping insulation in areas containing safety I
related equipment.
The intumescent coating has performed unsatisfactorily and we are switching to a combination of matetials which will provide equivalent protection to the intumescent coating.
The intumescent coating becomes very brittle when dry.
It easily cracks and flakes off insulation since the insulation remains pliable. This flaking i
reduces the protection provided and is a maintenance issue.
We have found a combination of materials that pro. vide equal or better protection and remains pliable when dry.
This combination is a primer coat of i
l Ar.uaflex followed by two coats of Flammastic.
We have reviewed the data available (flame spread and smoke density) on these two materials (Armaflex and Flammastic) and concluded they are better than the intumescent material.
We are using this combination for routine maintenance and insulation repair.
l Please let us know if you have any concerns with this switch in fire retardant coating for piping insulation.
l f))L4s,
V Thomas M Parker Manager l
Nuclear Support Services i
l c:
Regional Administrator Region Ill, NRC l
Senior Resident Inspector, NRC t
/
00' NRR Project Manager, NRC J E Silberg F
.