NRC Orders Post-Fukushima Safety Enhancements

The following story originally appeared in NEI’s Nuclear Energy Overview.

The U.S. Nuclear Regulatory Commission has issued orders to operators of nuclear energy facilities requiring enhanced protection of portable emergency equipment, hardened containment vents for some reactors and additional instrumentation for monitoring the water level in used fuel pools. In approving the orders, the commission agreed with the staff that the modifications outlined are sufficiently important to safety that the implementation cost need not be considered.

The first order requires companies to enhance the protection of portable emergency equipment added after the 2001 terrorist attacks and to obtain additional equipment to ensure their facilities can cope with events that may affect multiple reactors at a site. The industry’s “diverse and flexible coping capability,” or FLEX, is designed “to be fully responsive” to this order, said Anthony Pietrangelo, NEI senior vice president and chief nuclear officer. In February, the entire industry committed to procure additional equipment under the first phase of the FLEX program. In a subsequent phase, the industry will develop regional centers stocked with emergency equipment and supplies that can be rushed to a plant site if needed.

The second order requires reliable hardened vents for boiling water reactors with Mark I or Mark II containments. Of America’s 104 reactors, 31 use these designs. The companies that operate the 23 Mark I plants voluntarily installed hardened vents many years ago. However, the NRC said the reliability of these vents is not consistent. The eight Mark II plants, which have a slightly larger containment, do not have hardened vents.

The NRC has concluded that both containment types require the hardened vents to be “reliable.” Under the order, companies with Mark I plants will have to assess their current containment vent designs and, if necessary, modify them to ensure operators can operate the vents remotely and access them for manual operation. The NRC is still considering several policy issues related to vents, including whether they should include filters or be placed at other locations in addition to the containment structure. The NRC staff will address those questions in a paper due to the commission in July.

The third order requires additional instrumentation to monitor water levels in used fuel storage pools.

Plant operators are to submit plans for implementing the orders by Feb. 28, 2013. Modifications must be completed within two refueling cycles of that date or by Dec. 31, 2016, whichever is earlier. NEI is seeking clarification of the implementation schedule and the requirements for filing submittals.

The NRC has also issued a request for information pertaining to re-evaluations of seismic and flooding hazards, communications, and staffing during events affecting multiple reactors at a site. The commission’s March 9 letter to the staff takes into account the industry’s concerns about resource constraints in conducting seismic probabilistic risk assessments (PRA) and the importance of completing implementation of the new (pre-Fukushima) emergency preparedness rule before taking other actions.

“If the industry submits an alternative, practical engineering approach for seismic re-evaluations that could result in the quicker implementation of plant safety enhancements while enabling plants to complete the assessment within the schedule defined in the [information request],” the commission said, the staff should provide a report to the commission discussing whether the approach is acceptable. If the staff deems the industry’s approach not acceptable, it should explain “how continuing with the staff’s approach of seismic [PRA] provides superior safety benefits on a reasonable timetable.”

The commission said implementing the emergency preparedness rule issued last year “remains a higher priority” than activities associated with the NRC post-Fukushima task force recommendations in that area. “Completing implementation activities associated with the rule we have already promulgated has greater safety significance and also involves the coordinated actions of our partners in state and local governments,” the commission said. “Substantial public credibility benefits accrue from continuing these activities as a priority.”