Nuclear plant design needs blue sky approach

Nuclear plant design needs blue sky approach

Designers of nuclear plants should have more responsibility over plant design throughout the operating lifetimes of all their reactors, according to a new study by a working group of the World Nuclear Association (WNA).

 

World Nuclear Association

 

The WNA’s working group on Cooperation in Reactor Design Evaluation and Licensing (CORDEL) promotes standardization of nuclear reactor designs on the merit of improved economics and safety. It suggests that stronger involvement of the original designers would bring widespread safety and economic benefits to the nuclear industry.

The new study – entitled Aviation Licensing and Lifetime Management: What Can Nuclear Learn? – was written by CORDEL’s Design Change Management (DCM) Task Force. It compares the civil aviation industry’s approach to managing changes to aircraft design with the nuclear industry’s system of design change management. In the aviation industry, the original designer of a particular type of aircraft is always involved in the response to events and safety-relevant findings. In contrast, nuclear vendors do not have ongoing design responsibility for their reactors. This situation leads to differences between nuclear reactors of the same model.

In order to prevent marked differences in design occurring within a fleet of reactors, the DCM Task Force recommends that the benefits of standardization must be given full consideration in all design change decisions. “The vendor/designer should at least have an advisory role to ensure that important design improvements are implemented in all reactors of the same design around the globe,” the report states.

A 2012 report by the DCM Task Force – Design Change Management in Regulation of Nuclear Fleets – noted that improvements to the emergency venting system in boiling water reactors with Mark I containment systems – the type of reactor that was involved in the March 2011 accident at Japan’s Fukushima Daiichi plant – had been implemented according to the preferences of the individual operators.

Although the Fukushima accident was triggered by extreme events that were not considered in the design basis and subsequent modifications of the plant, the Task Force claims that this accident highlights the differences in the implementation of design changes such as upgrading the venting system. The Task Force acknowledges that every operator must have a sound knowledge and understanding of its plant; however, it claims the expectation that each utility should be the “design authority” for its plant could be both impractical and expensive.

Although some elements of voluntary coordination in the nuclear industry have been introduced by owners groups (which unite the vendor with the operators of nuclear units of the same design), the study points out that there is nevertheless no formal international system of design change management.

The DCM Task Force calls on the industry to move towards “stronger international cooperation of all stakeholders in a system of balanced and clearly attributed responsibilities.” The civil aviation industry’s system of international cooperation could serve as a model in this area, it suggests.

Source: World Nuclear News

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2 comments

  1. Lawrence Forsley

    General Electric and Hitachi built the Daiichi boiling water plants, based upon a GE design. GE managed to forestall NRC venting regulation changes in the US for over a decade, but they were eventually installed. As the article notes, the local operator, TEPCO, chose not to. Similarly, TEPCO designed the plants with the backup generators beneath the plants. Consequently, any disaster, in a earthquake and tsunami-prone country that resulted in activating those backups, might also find the backups compromised because of their poor location. If they’d been located above the reactors, the Daiichi disaster wouldn’t have occurred, as neither the reactors nor the spent fuel pools would have overheated and burned. Then, even the forced venting, and the consequent hydrogen-oxygen explosions wouldn’t have occurred either.

    The task force may wish that local operators take into account all known operational aspects of a particular nuclear power system. But, those operators are themselves embroiled in a variety of financial, management and political concerns. The means by which TEPCO, and various Japanese ministries, authorized the building, operation and monitoring of Daiichi, and all nuclear plants in Japan, provided an impenetrable shield to outsiders. Other countries will take similar views. Even the IAEA is unable to fully qualify what’s going on, with extreme examples being Iran and North Korea.

    Consequently, it’s not the same as the aircraft industry, where countries can remove landing rights to an aircraft not deemed safe: nuclear plants tend to stay where they are: except when venting, explosions or leakages occur.

  2. Pingback: Nuclear News Round Up (21st Jan – 25th Jan) « Assystem Energy & Nuclear

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