The following information is a synopsis of information received via facsimile:
Underwater Construction Corporation (UCC) was notified by Steris Isomedix Services (SIS) that test panels coated with Bio-Dur 560Blue epoxy coating, which SIS had been contracted to irradiate to a minimum accumulated dose of 1000 Mrad, could possibly have received a dose of only 949 Mrad due to a variance of 5.1 percent not previously reported on the Steris Component Irradiation Certificate. Bio-Dur 560Blue is a Service Level I coating. Failure to meet irradiation requirements for qualifying Service Level I coatings could result in the coating disbonding from the substrate, thus clogging Emergency Core Cooling Strainers during a postulated Loss of Cooling Accident (LOCA).
Bio-Dur 560Blue was used to reline the toruses at Peach Bottom Units 2 and 3. Also, 588 square feet of Bio-Dur 560Blue was applied to the liner of the suppression pool at Limerick Unit 1. UCC notified Exelon concerning the irradiation failure and provided the following recommendations:
- Perform evaluation of their Safety Analysis Report to determine if 949 Mrad meets licensing commitments.
- Perform a review and determine if Supplemental Test Report per Exelon Contract 00045628, Release 00735, whereby irradiation testing of Bio-Dur 560Blue was performed to 1000 Mrad by University of Massachusetts will provide reasonable assurance that coating will not fail during a LOCA.
Notification to NRC provided by Les Ayer,
UCC QA Manager, 860-767-8256, x-169.