How operators are driving key safety reforms from nuclear plant accidents

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Employees monitor a screen in a simulation of a control room at the D.C. Cook nuclear power station in Michigan in the US last month. Operators in the US are upgrading their plants to ensure reactors holding radioactive waste stay cool. PHOTO | ALLAN ODHIAMBO | NATION MEDIA GROUP 

By ALLAN ODHIAMBO

In Summary

• Nuclear safety became a major topic since the 2011 reactor meltdown at Japan’s Fukushima plant following an earthquake and tsunami accident that wreaked the facility.

In one of the backyards of the D.C. Cook nuclear power plant in Michigan, US, stands a special newly built thick-walled all-concrete structure officials say can withstand some of the most violent earthquakes and tornados.

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Inside this structure that sits on an elevated section of the vast compound on the shores of Lake Michigan is a new high-capacity stand-by power generator. In a separate yard less than 150 metres away another set of about six new power generators mounted on wheels are parked side-by-side overlooking the main power house.

“These are part of ongoing safety reforms to ensure we don’t have a repeat of the type of incident that happened at the Fukushima nuclear plant in Japan,” Bill Schalk, the communication manager at of American Electric Power (AEP) that owns the D.C. Cook power plant, said in reference to the power back-up units.

Nuclear safety became a major topic since the 2011 reactor meltdown at Japan’s Fukushima plant following an earthquake and tsunami accident that wreaked the facility. The incident has triggered a scramble for heightened safety measures among operators and regulators across the US, Europe and Asia to avoid a repeat.

“In nuclear safety we have to continuously learn and improve,” said Jack Grobe, the executive director of Exelon Nuclear Partners, part of Exelon Generation, which operates the largest nuclear power fleet in the US.

Like the rest of the world, nuclear plant operators in the US are now putting emphasis on areas such as back-up power during outages caused by severe flooding or earthquakes and are upgrading their plants to ensure reactors and pools holding radioactive waste stay cool even when the main power supply is lost.

“The primary lesson from Fukushima is to have other external sources of power to keep the plant running even in the event of an accident because power is key in the life of the plant,” Shane Lies, a Vice President in-charge of engineering at D.C. Cook nuclear plant, said.

In response to the Fukushima accident, the US Nuclear Regulatory Commission (NRC) issued a three-pronged safety strategy for implementation by 2016. A key recommendation by the regulator was to have nuclear plant operators develop comprehensive strategies for dealing with emergencies that may interrupt off-site power and compromise the safety of nuclear reactors.

It also advised nuclear plant operators to install more reliable instruments to measure water levels at cooling pools, where spent nuclear fuel is stored, and install hardened venting systems to prevent explosions caused by rapid build-up of hydrogen gas.

The regulator, however, said the two orders relating to emergency equipment and spent fuel pools will apply to every nuclear reactor in the US even though the order to install hardened vents is only applicable to US boiling-water reactors that have “Mark I” or “Mark II” containment structures.

The order, the regulator said, will have the nuclear reactors improve their venting systems to prevent or mitigate core damage in the event of an accident such as Fukushima. The NRC further required that every operator in the US analyse and update its earthquake and flood risks, conduct “walkdowns” at each plant and assess the ability to communicate in, and deal with, an emergency.

Nuclear power operators in the US are implementing the NRC recommended safety reforms that are estimated to cost at total $2.5billion on completion. The operators of D.C. Cook Nuclear Power plant plan to invest about $50 million to stabilise alternative emergency power supplies through measures such as back-up batteries and generators.

Keen to learn

“We hope to be among the first to comply with the post-Fukushima reforms,” Mr Lies said.

Experts said these reforms such as those being implemented by the US nuclear power plant operators have been adopted globally as operators and regulators laid emphasis on learning from incidents and experiences among peers to enhance safety.