Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
SSINS No. 6835
IN 83-33
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON D.C. 20555
May 26, 1983
Information Notice No. 83-33: NONREPRESENTATIVE SAMPLING OF
CONTAMINATED OIL
Addressees:
All nuclear power reactor facilities holding an operating license (OL) or a
construction permit (CP).
Purpose:
This information notice is provided as notification of events that had
potential radiological impact on the general public. It is expected that
recipients will review the information for applicability to their
facilities. No specific action or response is required.
Description of Circumstances:
Over the past several years, inadequate sampling of waste oil has resulted
in incorrect determinations of waste oil contamination at three nuclear
power plants. These events resulted in the inadvertent release of licensed
material beyond the plant's radiologically controlled areas.
In late 1980, a licensee attempted to mix the contents of waste oil drums,
which included water, with a stirring rod. Oil and water within the drums
were not adequately mixed. Subsequent analysis of the samples from these
drums did not reveal that radioactive contamination was present. The drums
were transferred outside the owner's protected area to await pickup by a
waste oil vendor. The vendor subsequently pumped the oil from the drums
until he reached water. The water was discharged to the ground surrounding
the waste oil storage area. Several years of this practice resulted in an
accumulation of radioactivity in the soil. Contact radiation readings on the
soil's surface were as high as 100 mrem/hr. It was evident that unsampled
water in the drums was significantly radioactive. Since stirring did not
provide sufficient agitation to provide a homogenous mixture of oil and
water, this licensee erroneously determined that the waste oil drums were
free of contamination.
In October 1982, another nuclear power plant was found to be sampling waste
oil without assuring adequate mixing to obtain a representative sample.
Their method of sampling, coupled with inadequate counting techniques,
resulted in licensed material being released to a waste oil vendor, an
unauthorized recipient.
8303040046
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IN 83-33
May 26, 1983
Page 2 of 2
In November 1982, it was discovered that another licensee had been releasing
waste oil containing licensed material to a waste oil vendor. The licensee
attempted to mix the contents of the waste oil drums employing a stirring
rod on which two small propellers were mounted and driven by a variable
speed drill. The licensee then obtained a one-liter sample from the drum
for counting. This licensee performed an experiment in which the contents
of a 55-gallon drum containing 75% waste oil and 25% water were mixed,
employing the above technique. A sample was drawn from the drum and
centrifuged. Only three percent of the sample was water. Upon discovering
that this method of sampling was nonrepresentative, the licensee
discontinued the method.
Because of the obvious difficulty in obtaining a representative sample from
oil-water mixtures, the amount of water in the waste oil should be
minimized.
The radioactive contamination may be present in only the oil or the water
fraction, thereby potentially causing misleading results in even well mixed
samples. Consequently, emphasis should be placed on (1) minimizing, if not
eliminating, the amount of water in waste oil mixtures and (2) testing
waste-oil sampling techniques to confirm that representative samples are
being obtained.
No written response to this information notice is required. If additional
information is needed, with regard to this subject, please contact the
Administrator of the appropriate NRC Regional Office.
Edward L. Jordan, Director
Division of Emergency Preparedness
and Engineering Response
Office of Inspection and Enforcement
Technical Contact: C. Campbell, IE
301-492-9762
Attachment:
List of Recently Issued IE Information Notices
.
