Sweden submits revised action plan

07 January 2015

The Swedish nuclear regulator has submitted a revised post-Fukushima safety action plan to the European Commission which incorporates independent core cooling requirements announced last year.

All European nuclear power plants were required to undergo stress tests following the March 2011 accident at Japan's Fukushima Daiichi plant. Recommended safety improvements were drawn up through peer reviews of these stress tests.

Cooling requirements

In October 2014, SSM announced a two-stage set of upgrades it wants to see at the country's ten operating nuclear power reactors.

By 2017, all reactors should have independent systems to ensure power and water are available for emergency cooling for a period of 72 hours. This is in common with post-Fukushima upgrades undertaken in many countries, and already in progress in Sweden under the power plant operators' own initiative. SSM said this requirement could be met by means such as mobile diesel generators and external water storage.

By 2020, SSM wants the plants to have a "robust permanent installation that includes power supply and systems for pumping of water and an external water source independent of those used in existing emergency cooling systems." This is significantly more complicated, requiring engineering deep within the reactor building and potentially its primary coolant circuit.

The ENSREG Action Plan, approved in August 2012, specified the need for national action plans for implementing these additional safety measures to be made publicly available by the end of 2012 and to peer review them. Revised national action plans were due by the end of December 2014.

The Swedish Radiation Safety Authority (StrÄlsÀkerhetsmyndigheten, or SSM) submitted its original action plan in December 2012. It submitted the revised plan to the independent European Nuclear Safety Regulators Group (ENSREG) on 31 December 2014. SSM said the revised plan includes the implementation of independent core cooling requirements at Swedish plants.

SSM said, "For the most part, the Swedish national action plan presents investigations whose aim is to determine and consider which measures are fit for purpose, how they shall be implemented as well as the point in time for this." It added, "For Sweden, the introduction of independent core cooling is one of the most important measures."

The regulator said the safety measures listed in the plan are scheduled in three different categories - 2013, 2014 and 2015 - corresponding to the year when the measures shall be completed. However, it said it is "highly likely that the majority of necessary technical and administrative measures will be implemented after 2015, due to a high degree of complexity, though it's important that all necessary measures will be implemented as soon as reasonably possible." SSM added that all necessary actions shall be fully implemented before the end of 2020.

Public feedback on the revised national action plans can be submitted via the ENSREG website by 28 February.

ENSREG plans to hold a workshop in April 2015 where all countries are expected to show how work is progressing in implementing their respective action plans.

Researched and written
by World Nuclear News