The Tennessee Valley Authority’s Watts Bar Unit 2 reactor, which began producing tritium for nuclear weapons on Nov. 19, will irradiate a bit more than half as many tritium-producing rods as hoped in fiscal year 2021, the National Nuclear Security Administration said Tuesday.
The semi-autonomous Department of Energy nuclear-weapons agency had aimed to irradiate 992 tritium producing burnable absorber rods (TPBARs) in Watts Bar 2 in the fiscal year that started Oct. 1 but “chose to pursue the irradiation of 544 available TPBARs in 2021,” a spokesperson wrote in an email.
Watts Bar Unit 2 is on its fourth fuel cycle, which began in November after a refueling outage that lasted a little less than a month. Power-generating cycles nominally last about 18 months for the two Watts Bar reactors, but Unit 2 is scheduled to shut down in August or September, about eight to 10 months into cycle four, so the Tennessee Valley Authority can take another look at a degraded steam generator it noticed during the fall 2020 outage.
The authority was planning to replace the generator in 2024 but has pushed the swap up to 2022, according to company filings this year and last year with federal regulators.
Meanwhile, Watts Bar Unit 1, which has irradiated TPBARs since 2003, is still going strong. Unit 1 is now on its 17th cycle, during which it will irradiate 1,792 TPBARs according to the National Nuclear Security Administration’s (NNSA) 2021 budget request.
With a crush of nuclear weapon refurbishments coming down the pike, the NNSA wants to increase the combined tritium output of the Watts Bar reactors to about 2,800 grams per cycle by Sept. 30, 2025.
“The Tritium Modernization Program remains committed to increasing TPBAR quantities in future cycles,” the NNSA spokesperson wrote on Tuesday.
