The following story originally appeared in NEI’s Nuclear Energy Overview.
NEI has asked the NRC to endorse the industry’s guidance for complying with the agency order requiring that nuclear energy facilities be equipped with instruments to reliably indicate used fuel storage pool water levels in an emergency.
In a July 5 letter to the agency, Adrian Heymer, NEI’s executive director for strategic programs, submitted for NRC review and endorsement the latest revision of the industry guidance document (NEI 12-02, Revision 0, Industry Guidance for Compliance with NRC Order EA-12-051, To Modify Licenses with Regard to Reliable Spent Fuel Pool Instrumentation). The document incorporates NRC comments on a previous version that was endorsed by agency staff.
In its report last year, the NRC’s Fukushima task force said that equipping used fuel storage pools with reliable level instrumentation would “significantly enhance the knowledge of key decision makers,” allowing them to respond more effectively in the event of a very low-probability beyond-design-basis accident.
The agency in March turned the task force’s near-term recommendation into an order that all reactor operators should have reliable indications of water levels in used fuel pools.
The order specifies that the instruments should reliably indicate water levels at three critical depths. At the highest indicated level, the normal fuel pool cooling systems are still operable. The middle level indicates that adequate radiation shielding is available for personnel on the pool operating deck, while at the lowest level the used fuel is covered with water but the addition of makeup water can no longer be deferred. A single instrument need not measure the entire range of pool depth.
The order also requires all reactor operators to provide:
- primary and back-up level instruments that would monitor water level from the normal level to the top of the used fuel rack in the pool;
- a display in an accessible area following a severe event, and
- independent electrical power to each instrument channel as well as the capability to connect an alternate remote power source.
The back-up instruments may be fixed, portable or a combination. All instruments must be reliable under high-temperature, high-humidity and high-radiation conditions, and must remain functional “until additional off-site resources are obtained, deployed and spent fuel pool conditions are stabilized.”
NEI’s guidance document details the industry’s approach for complying with the specifications in the order. The guidance is meant to complement the industry’s diverse and flexible (“FLEX”) approach to mitigating extreme natural events.
Heymer said the intent is for the NRC to issue its final guidance in August, endorsing NEI 12-02.
Utilities are expected to comply with the order by the end of 2016, or within two refueling outages following submittal of a required integrated plan on the order.