[12] A new management team had been put in place by HL&P in late 1978 to deal with the cost overruns, schedule delays and other challenges.

[citation needed] However, events at Three Mile Island in March 1979 had a substantial impact on the nuclear industry including STNP.

[citation needed] HL&P executives consulted with its own project manager and concluded that Brown and Root was not making satisfactory progress and a decision was reached to terminate their role as architect/engineer but retain them as constructor.

[citation needed] The history of STNP is somewhat unusual since most nuclear plants that were in the early stages of engineering construction at the time of the Three Mile Island event were never completed.

[citation needed] On June 19, 2006, NRG Energy filed a letter of intent with the NRC to build two 1,358-MWe advanced boiling water reactors (ABWRs) at the South Texas Nuclear Project site.

[citation needed] On September 24, 2007, NRG Energy filed an application with the NRC to build two Toshiba ABWRs at the South Texas Nuclear Project site.

[citation needed] In October 2009, main contractor Toshiba had informed CPS Energy that the cost would be "substantially greater," possibly up to $4 billion more.

[citation needed] In October 2010, the South Texas Project announced that the Tokyo Electric Power Company (TEPCO) had entered into an agreement with Nuclear Innovation North America (a joint venture between the reactor manufacturer, Toshiba, and plant partner NRG Energy) which was the largest of the two stakeholders in the proposed reactors, to purchase an initial 9.2375% stake in the expansion for $125 million, and $30 million for an option to purchase an additional stake in the new units for $125 million more (resulting in approximately 18% ownership by TEPCO, or 500 MW of generation capacity).

The agreement was made conditional upon STNP securing construction loan guarantees from the United States Department of Energy.

Anti-nuclear campaigners alleged that the financial situation of new partner TEPCO, combined with the ongoing Fukushima nuclear accident were also key factors in the decision.

According to a Nuclear Regulatory Commission report, the low steam generator levels were due to loss of feedwater pumps 11 and 13.

Nuclear whistleblower Ronald J. Goldstein was a supervisor employed by EBASCO, which was a major contractor for the construction of the South Texas plants.

[32] The Nuclear Regulatory Commission's estimate of the risk each year of an earthquake intense enough to cause core damage to the reactor at South Texas was 1 in 158,730, according to an NRC study published in August 2010.