Safety of Gas Line and Gas Plant Operations

In light of recent gas-related explosions in the utility industry, we conducted a review of Tennessee Valley Authority's (TVA) safety of gas line and gas plant operations. The objective of our review was to determine if TVA has taken appropriate steps to identify and mitigate risk associated with the operation of gas plants and gas lines. We found that the vast majority of gas-related explosions were gas line related. According to TVA personnel, TVA is not responsible for gas until it reaches the reducing stations on TVA property. This significantly decreases TVA's risk of a gas-related incident. We did identify explosions in Middletown, Connecticut and Garner, North Carolina that occurred at gas plants due to improper commissioning. In both instances, fuel gas was used to clean or purge gas pipes of debris, air, or other substances. TVA has taken steps to mitigate this risk by using compressed air instead of gas to clean or purge gas pipes.As part of TVA's Risk Management program, the organization has identified asset performance vulnerability. Asset performance vulnerability impacts TVA's ability to provide power when there is a demand. The risk for asset performance vulnerability is driven by equipment-failure-related incidents that cause forced-outage events and planned-outage extensions of significant duration. According to TVA's Risk Management program, the severity for asset performance vulnerability is moderate. TVA has mitigated these risks. In addition, TVA has completed the draft of a Natural Gas Piping System Management manual. This manual provides the primary standards and methodology required for the commissioning, maintenance, and integrity management of natural gas piping systems found at TVA fossil power group properties.