NRC Approves New Beyond Design Rules

The Nuclear Regulatory Commission (NRC) on Thursday issued a pared-down version of the new Mitigation of Beyond-Design-Basis Events rules, a 212 page document that spells out the latest safety enhancements required of U.S. nuclear power plants as a reaction to the 2011 meltdown disaster at the Fukushima Dai-ichi power plant in Japan.

NRCBy dollars and cents, the rule is a significant backpedaling from the first draft, which had the cost to energy company compliance estimated at $1.7 million per site. The new draft, with the $1.7 figure crossed out, puts the cost per site at $110,000 (per site) using a 7 percent discount rate,” the document says.

The Union of Concerned Scientists called the final draft a “stripped-down version” of the original, pointing out that post-construction estimates of potential threats at various plants pointed to increased risks. Nuclear Energy International President and CEO Maria Korsnick, however, quoted by Power Magazine, said the trimmed-down version was the result in the agency’s confidence that the nation’s nuclear plants were safe. Korsnick added that post-construction safety enhancements, including additional equipment at nuclear plants had already exceeded $4 billion.

The final version, which was approved 3-2 by the NRC’s five commissioners, is the next post-Fukushima step taken by the agency that said it would continue to seek other rule amendments to enhance security and safety at nuclear power sites.

The highlights of the final version include directing plants to maintain safety functioning at nuclear power plants in the event of a “beyond design” incident, such as the powerful earthquake that rocked the Fukushima Dai-ichi power plant and triggered a 14 meter high tsunami event that overran the plant's backup safety systems. The rule is intended to underscore the need for U.S. plants to keep reactors and spent fuel cool despite the potential loss of A/C electricity that would normally power the plant’s back up systems. Ensuring containment of radioactive materials and continued cooling of reactor cores and spent fuel are central to the rules that will go into effect 30 days after a notice on the rules is posted in the Federal Register, which is to occur in the next few months. 

The NRC reacted quickly after the Fukushima Dai-ichi accident and within a week after March 11, 2011, when the Great East Japan Earthquake struck, the agency had already assembled a Near Term Task Force made up of senior officials who were tasked with reviewing the agency’s rules and procedures to find ways they could be improved.

The Near-Term Task Force came up with 12 recommendations, most of them focused on securing operational instrumentation during a blackout event and ensuring the safety of the plant in the event of a long-term power outage. In response, the agency moved to have plants upgrade backup systems in the 2012 Mitigation Strategies Order that was paired with the agency’s Spent Fuel Pool Instrumentation Order, which mandated continuous and reliable data on water levels in cooling pools.

While many rule changes mandated more reliable safety systems, the agency also took the opportunity to streamline some regulations.

In the final version released Thursday, the agency retreated from earlier drafts that called for new evaluations of plant safety with regards to earth tremors, earthquakes, flooding and other natural hazards, such as hurricanes. The agency had previously put 33 plants on alert with regards to new Seismic Probabilistic Risk Assessments they were ordered to do. The final version, however, revises that approach, giving more leeway to licensees.

”The final rule is revised to remove reference to the reevaluation hazards, allowing licensees to address them within their mitigating strategies in a flexible and appropriate manner,” the final draft says.

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  • Anonymous

    Step in the right direction, but still costs are killing big nuclear plants.   Must move to SMRs which are PERFECT for African nations with their small towns and vast distances between and weaker economies that simply cannot do big nuclear plants.