United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 83-33: Nonrepresentative Sampling of Contaminated Oil

                                                             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

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