The 1150-MW Watts Bar-2 nuclear reactor is expected to enter commercial operation in southeastern Tennessee later this summer, a mere 43 years after construction began.
But two days into the testing period, while operating at 12.5% capacity, “the reactor tripped when a high-pressure turbine valve failed to open,” RenewEconomy reports, citing the U.S. Nuclear Regulatory Commission (NRC).
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In a post that was republished by the Energy Information Administration, the Tennessee Valley Authority boasts that Watts Bar-2 was the first nuclear plant connected to the U.S. grid since 1996, when Watts Bar-1 went into operation. Construction began in 1973, was halted in 1985, then restarted in 2007.
“At that time, a study found Unit 2 to be effectively 60% complete with $1.7 billion invested,” the TVA writes. “The study said the plant could be finished in five years at an additional cost of $2.5 billion. However, both the timeline and cost estimate developed in 2007 proved to be overly optimistic, as construction was not completed until 2015, and costs ultimately totaled $4.7 billion.”
In his recap of the decades-long project, Craig Morris of Renewables International recalls the TVA’s urgent arguments to expedite construction, claiming that a May 1977 startup for Watts Bar-1 was “vital in order to permit-TVA to meet its summer 1977 peak loads” and beyond.
“The present schedule for constructing the Watts Bar Nuclear Plant is predicated on beginning construction in October 1972,” the utility wrote at the time. “This schedule is extremely tight and failure to begin construction in October casts serious doubts on TVA’s ability to meet its load commitments in the 1977-78 period.”
Morris reports that the ice condenser design of both reactors makes them vulnerable to hydrogen buildup and containment failure. In February 2013, the NRC censured TVA in February 2013 for “using outdated and inaccurate calculations in estimating the maximum potential flood threat should upriver dams be breached, the end result of which could be loss of cooling function and reactor meltdown.”
Earlier this year, TVA “announced that flood prevention measures built at the plant to meet post-Fukushima requirements had risen to US$300 million, compared to the US$120 million estimated four years ago,” he writes.
