NRC Opens Special Investigation at Watts Bar
The residual heat removal system was inoperable for a time on both units of the TVA nuclear plant on some days in April.
The Nuclear Regulatory Commission has opened a special investigation at the Watts Bar nuclear power plant near Spring City, Tenn., saying April 30 that it concerns "the circumstances surrounding voids in the residual heat removal system," which as a result was inoperable for a time on both units of the TVA-operated nuclear plant on some days in April.
The system is used to complete the plant's cooldown process at lower pressures, and it also provides important functions during certain accident scenarios, according to the NRC news release. TVA informed the agency April 19 that calculation revisions had reduced the acceptable size of a void due to gases in the system, and on April 21 and 22, accumulated gas in each unit's system was found to have exceeded the acceptable value, according to the release.
NRC inspectors will review the event, calculations, acceptance criteria, and assess the adequacy of TVA's actions to address the causes of the issues. An inspection report should be issued with 45 days.