Wednesday, September 28, 2016

NRC and Palo Verde Focus on Making Nuclear Outages Safer with FLEX

Bob Bement
The following is a guest post by Bob Bement, Executive Vice President at the Palo Verde Nuclear Generating Station (PVNGS).

Learnings from the accident at the Fukushima Daiichi plant in March of 2011 are actually impacting U.S. nuclear industry operations today, making a safe fleet even safer.

One of the most significant post-Fukushima initiatives was the implementation of Diverse and Flexible Coping Strategies (FLEX), which utilizes reliable portable equipment to provide operators with a powerful tool box for responding to the most extreme situations. The industry has made great strides in improving safety using the portable equipment to protect against events similar to the one at Fukushima, however there is still significant potential for increasing safety in other areas with this equipment. We’re doing just that at Palo Verde today and, with the support of the Nuclear Regulatory Commission (NRC), it will be done industry-wide.

Palo Verde achieved a green risk level for the full duration of our latest spring outage. We accomplished this by deploying the extra sets of FLEX equipment to serve as an additional level of defense while performing maintenance functions. It’s important to note that before any of these strategies are implemented, personnel ensure that these uses would not cause a potential for the plant to shut down automatically, or they would not potentially fail or actuate a safety-related system.

One innovative strategy we implemented was deploying a FLEX pump to provide temporary back up cooling to the spent fuel pool. Having this pump staged allowed the option of providing cooling from an alternate water tank while the normal back up water tank was undergoing normal maintenance during our outage. Additionally, Palo Verde deployed portable FLEX generators while online as backups to improve safety. The generators were connected in a way to prevent any adverse impacts on the plant.
Jason Seymour of APS inspects a mobile pump.
Last May, David Lochbaum from the Union of Concerned Scientists visited Palo Verde and saw firsthand how we were implementing this equipment and taking necessary precautions. By staging this equipment, we not only improve safety directly, but we familiarize our personnel with the FLEX equipment and how to deploy it.
The site is justifiably proud of its successes; it is also aware of the consequences from failure. Complacency is an easy trap to fall into. While no one desires to be trapped, the PVNGS backs up its desire with vigilant awareness.

–David Lochbaum, Union of Concerned Scientists
Originally, operators ran nuclear plants using technical specifications, and then we added risk management action levels. Now we want operators to always consider how they can improve plant safety using FLEX equipment.

Staff at Palo Verde explain use of FLEX equipment.
Key leaders from NRC came out to Palo Verde earlier this month, to see firsthand how we are leading the use of FLEX equipment in this innovative manner. One area of ongoing discussion is with the effectiveness of the FLEX preventative maintenance (PM) programs. The industry and NRC invested a significant amount of resources into FLEX, including implementation of an approach to the PM programs that would be used industry-wide, ensuring its effectiveness. These programs continue to be rigorous enough for additional beyond design basis enhancements to safety.

The industry and the NRC have a common goal of improving safety using FLEX equipment. I believe that NRC leadership recognizes the potential of this equipment. Fortunately, our joint efforts on FLEX implementation over the last five years have laid the foundation to improve safety in this innovative way.

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