Development of a Site Specific Biofouling Control Program for the Diablo Canyon Power Plant

In 1983, Pacific Gas and Electric Company (PGandE) biologists began a study designed to develop a macrofouling control program for the Diablo Canyon Power Plant. Preliminary studies indicated that heat treatment was best suited to the DCPP site. The optimal heat treatment strategy would minimize the number of heat treatments per year, maximize biofouling control, and minimize potential environmental impacts. The study consisted of a laboratory determination of the themal tolerance of major biofouling species, a determination of growth rates and periods of peak settlement, and simulations of heat treatment on actual fouling communities. Physical model studies predicted the areal extent of discharge plumes. Environmental effects were assessed from laboratory studies. Results of all study phases were integrated to develop the biofouling control program now in use. The number of heat treatments during the first year of operation was reduced from twelve to three. This resulted in a cost savings in excess of $11 million.