The US Nuclear Regulatory Commission (NRC) has proposed a $70,000 civil penalty against the Tennessee Valley Authority (TVA) for violating the quality assurance regulations at Watts Bar nuclear plant Unit 2.

NRC said in the inspection, which was conducted in late 2012 and early 2103, it found three violations related to the plant’s commercial grade dedication program.

The commission’s inspectors found a breakdown in the program resulting in construction of unknown quality.

NRC said TVA has failed to report the breakdown and identify the issue as a significant condition affecting quality.

NRC Region II deputy administrator for construction Fred Brown said, "While TVA has aggressively addressed these issues, the violations and proposed civil penalty emphasize the importance of an effective quality assurance program during construction as well as prompt identification and reporting of any related breakdowns."

The latest fine will bring TVA’s penalties paid to the NRC to $268,000 as the authority has earlier paid fines for violations at the Sequoyah and Watts Bar plants in the US.