DOE evaluates changes to tritium production program at TVA reactors

The U.S. Department of Energy on Feb. 24 releaed a Final Supplemental Environmental Impact Statement for the production of tritium in a Commercial Light Water Reactor.

This document supplements DOE’s 1999 Final EIS, which addressed the production of tritium in Tennessee Valley Authority (TVA) reactors at Watts Bar Unit 1 in Rhea County, Tenn., and Sequoyah Units 1 and 2 in Hamilton County, Tenn., using tritium-producing burnable absorber rods (TPBARs). After several years of production experience at Watts Bar 1, the National Nuclear Security Administration (NNSA) determined that it needed to produce less tritium than previously anticipated. In addition, the Final SEIS analyzes impacts associated with higher than expected tritium permeation and includes three additional alternatives that address options for providing needed tritium in the event of a reactor outage.

The 1999 EIS addressed the production of tritium in TVA reactors using TPBARs and analyzed the potential environmental impacts of irradiating up to 3,400 TPBARs per reactor operating on an 18-month fuel cycle. The 1999 EIS included TPBAR irradiation scenarios using multiple reactors to irradiate a maximum of 6,000 TPBARs every 18 months.

In 2002, TVA received license amendments from the U.S. Nuclear Regulatory Commission (NRC) to produce tritium in those reactors. Since 2003, TVA has been producing tritium for the NNSA by irradiating TPBARs only in Watts Bar 1. However, irradiation of TPBARs in the Sequoyah reactors has remained a viable option. After irradiation, NNSA transports the TPBARs to the Tritium Extraction Facility at the DOE Savannah River Site in South Carolina.

NNSA has prepared this SEIS because there is new information about the amount of tritium required to support the nation’s requirements and because TVA’s experience in irradiating TPBARs has produced new information relevant to the potential environmental impacts at irradiation reactor sites that was not available when the 1999 EIS was prepared. This SEIS does not revisit DOE’s tritium extraction activities because the actions described in this SEIS would result in the extraction of tritium from fewer TPBARs at the Tritium Extraction Facility with subsequently fewer environmental impacts at the Savannah River Site than the 1999 EIS analyzed.

During irradiation of TPBARs in a reactor, while the great majority of tritium is captured inside the TPBARs, a small amount diffuses through the TPBAR cladding into the reactor coolant; this is called permeation. Based on several years of production experience at Watts Bar 1, NNSA has determined that tritium permeation through the cladding occurs at a higher rate than the 1999 EIS projected and analyzed; nevertheless, tritium releases to the environment have been below regulatory limits.

NNSA has prepared this SEIS to analyze the potential environmental impacts from TPBAR irradiation at TVA sites based on a high and thus conservative estimate of the tritium permeation rate and NNSA’s revised estimate of the maximum number of TPBARs necessary to support the current tritium supply requirements. The proposed action this SEIS evaluates is to irradiate up to a total of 2,500 TPBARs every 18 months in one or more TVA reactors.

There are two reactors at both the Watts Bar site and the Sequoyah site; although Watts Bar 2 is not currently operational, the NRC is currently reviewing the Watts Bar 2 operating license application, and this SEIS assumes that Watts Bar 2 will receive an operating license.

Near-term tritium requirements are more likely to be met with the irradiation of 2,500 TPBARs, but this does not exclude the possibility that future needs may require irradiating additional TPBARs. Various unanticipated events could necessitate increasing TPBAR irradiation, including but not limited to changes in the NNSA’s requirements for tritium or to compensate for a prolonged reactor outage. Therefore, this SEIS also evaluates a maximum production scenario of irradiating 5,000 TPBARs every 18 months. In any event, the exact number of TPBARs to be irradiated will be determined by both national security requirements and TVA reactor availability, with no more than 5,000 TPBARs irradiated during an 18-month cycle.

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.