While reviewing Unit 1, Train A, engineering safeguard features test deficiency data on October 22, 2008, the inspectors identified that the accelerated sequencer function was not described in the
UFSAR. The licensees
UFSAR commits to
Regulatory Guide 1.70, Standard Format and Content of Safety Analysis Reports for Nuclear Power Plants, Revision 1 and 3, for the format and content of the
UFSAR.
RG 1.70, Revision 1, Section 8.3.1.1 states to Describe the onsite A.C. power systems with emphasis placed on those portions of the systems that are safety-related. Those portions of the onsite A.C. power system that are not related to safety need only be described in sufficient detail to permit an understanding of their interactions with the safety-related portions. The description of the safety-related portion should include: (8) automatic loading and stripping of buses. The inspectors review concluded that the accelerated sequencer function can sequentially energize various safety equipment (partitioned into load groups) from the safety-related emergency A.C. power system during design basis accidents described in
UFSAR Chapter 15. This accelerated sequencer function will automatically energize the next safety load group, after 2 seconds, if the emergency A.C. bus voltage and diesel engine speed recover to values of approximately 92.5% and 97%, respectively. If after energizing certain safety load groups, the bus voltage or diesel speed permissives are no longer met, the accelerated sequencer function will drop out the start signal and those loads will become de-energized until the permissives are met again or the separate
UFSAR described load sequencer function re-energizes those loads based on a timed sequence. Pending NRC review of the enforcement aspects of this issue and review of the licensees operability evaluation, this issue is identified as an Unresolved Item:
URI 05000369,370/2008005-02, Accelerated Sequencer not Described in the
UFSAR. The licensee generated
PIPs M-08-6767 and M-09-0063 to address this concern
