The Tennessee Valley Authority has awarded a seven-year contract to Philadelphia-based Day and Zimmerman to supply workers and temporary help during outages at TVA’s nuclear power plants, the Times Free Press reports. The contract, which TVA directors approved at their quarterly board meeting in Knoxville this week, is valued at $950 million through 2023 and could be extended for an additional three years, according to TVA Nuclear Chief Joe Grimes. Day & Zimmerman’s business units include Yoh, a Philadelphia-based technology staffing provider.