Information Notice No.80-09 – Possible Occupational Health Hazard Associates with Closed Cooling Systems for Operating Power Plants
SSINS: 6870
Accession No.:
7912190681
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D.C. 20555
March 7, 1980
Information Notice No. 80-09
POSSIBLE OCCUPATIONAL HEALTH HAZARD ASSOCIATES WITH CLOSED COOLING SYSTEMS
FOR OPERATING POWER PLANTS
As a result of information that the causative agent for meningoencephalitis,
the amoeba Naeglaria fowleri, had been found in warm water ponds in Florida
and Texas where two fatalities were reported, NRC initiated a study by Oak
Ridge National Laboratory on the occurrence of Naeglaria in power plants
with closed cycle cooling systems. For seven power stations examined (6
fossil, 1 nuclear), this study confirmed the presence of pathogenic
Naeglaria at three plants including the nuclear plant (Dresden).
Recently, Northern States Power Company (NSP), while monitoring the Prairie
Island Nuclear Generating Plant closed cooling system for the amoeba, did
identify the presence of Naeglaria. Although the Minnesota Department of
Health does not consider the existence of the organism to be a public
health threat, it was recognized as a possible occupational health hazard.
Plant personnel were instructed to wear rubber gloves when coming into
contact with the circulating water and to wear respirators when working in
the area of the cooling towers. In November 1979, NSP conducted a special
chlorination program at Prairie Island that was designed by Dr. Richard
Tyndall of Oak Ridge to eradicate this organism. Chlorine concentrations in
the circulating water system was raised to 2.0 mg/l (measured as free
chlorine) for a period of six hours to destroy both the amoebae and its
encysted form. This program also included dechlorination prior to discharge
and intensive monitoring to document chlorine concentrations, the impacts of
chlorinated cooling tower draft and sampling to determine the efficacy of
the special chlorination program in destroying Naeglaria. Preliminary
results indicate that the program was successful in reducing the number of
organisms present by two to three orders of magnitude.
It is recognized that there have been no reported cases of
meningoencephalitis reported among power plant personnel to date; however,
the seriousness of the disease (if contracted) and the confirmed presence of
Naeglaria at four plants, leads us to inform all licensees with closed cycle
cooling water systems of the potential occupational hazard and advise that
they take appropriate action.
No written response to this Information Notice No. is required. If you desire
additional information regarding this matter, contact the Director of the
appropriate NRC Regional Office.
Page Last Reviewed/Updated Thursday, March 25, 2021