NRC Issues Interim Staff Guidance on Post-Fukushima Containment Venting Requirements

The NRC has released Japan Lessons-Learned Interim Staff Guidance JLD-ISG-2015-01 to provide guidance on compliance with Phase 2 of Order EA-13-109, ‘‘Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation under Severe Accident Conditions.’’  Following the Fukushima-Daiichi accident, the NRC required Boiling Water Reactors (BWR) with Mark I or II containments to upgrade or install a hardened containment venting system.  Order EA-13-109 addressed a follow-up issue related to the performance of these venting systems during severe accident conditions.  The Order adopted a phased approach to implementation of venting capabilities from the wetwell and drywell.  JLD-ISG-2015-01 provides guidance for compliance with Phase 2 of the Order, which requires installation of a reliable, severe accident capable drywell vent system or the development of a reliable containment venting strategy that makes it unlikely that a licensee would need to vent from the containment drywell during severe accident conditions.  The ISG endorses, with some clarifications, NEI 13-02 Rev. 1, which provides guidance on the same topic.

To view the Federal Register entry, click here.

To view the Interim Staff Guidance, click here.