United States Nuclear Regulatory Commission - Protecting People and the Environment


                                                             SSINS:  6830  
                                                             Accession No.: 
                                                             8103300375    
                                                             IEC 81-07     

                               UNITED STATES 
                       NUCLEAR REGULATORY COMMISSION 
                    OFFICE OF INSPECTION AND ENFORCEMENT 
                           WASHINGTON, D.C. 20555 
                                     
                                May 14, 1981 

IE Circular No. 81-07: CONTROL OF RADIOACTIVELY CONTAMINATED MATERIAL 

Description of Circumstances: 

Information Notice No. 80-22 described events at nuclear power reactor 
facilities regarding the release of radioactive contamination to 
unrestricted areas by trash disposal and sale of scrap material. These 
releases to unrestricted areas were caused in each case by a breakdown of 
the contamination control program including inadequate survey techniques, 
untrained personnel performing surveys, and inappropriate material release 
limits. 

The problems that were described in IE Information Notice No. 80-22 can be 
corrected by implementing an effective contamination control program through
appropriate administrative controls and survey techniques. However, the 
recurring problems associated with minute levels of contamination have 
indicated that specific guidance is needed by NRC nuclear power reactor 
licensees for evaluating potential radioactive contamination and determining
appropriate methods of control. This circular provides guidance on the 
control of radioactive contamination. Because of the limitations of the 
technical analysis supporting this guidance, this circular is applicable 
only to nuclear power reactor facilities. 

Discussion: 

During routine operations, items (e.g., tools and equipment) and materials 
(e.g., scrap material, paper products, and trash) have the potential of 
becoming slightly contaminated. Analytical capabilities are available to 
distinguish very low levels of radioactive contamination from the natural 
background levels of radioactivity. However, these capabilities are often 
very elaborate, costly, and time consuming making their use impractical (and
unnecessary) for routine operations. Therefore, guidance is needed to 
establish operational detection levels below which the probability of any 
remaining, undetected contamination is negligible and can be disregarded 
when considering the practicality of detecting and controlling such 
potential contamination and the associated negligible radiation doses to the 
public. In other words, guidance is needed which will provide reasonable 
assurance that contaminated materials are properly controlled and disposed 
of while at the same time providing a practical method for the uncontrolled 
release of materials from the restricted area. These levels and detection 
capabilities must be set considering these factors: 1) the practicality of 
conducting a contamination survey, 2) the potential of leaving minute levels 
of contamination undetected; and, 3) the potential radiation doses to 
individuals of the public resulting from potential release of any 
undetected, uncontrolled contamination. 
.

                                                            IEC 81-07     
                                                            May 14, 1981  
                                                            Page 2 of 3   

Studies performed by Sommers1 have concluded that for discrete particle 
low-level contamination, about 5000 dpm of beta activity is the minimum 
level of activity that can be routinely detected under a surface 
contamination control program using direct survey methods. The indirect 
method of contamination monitoring (smear survey) provides a method of 
evaluating removable (loose, surface) contamination at levels below which 
can be detected by the direct survey method. For smears of a 100cm2 area (a 
de facto industry standard), the corresponding detection capability with a 
thin window detector and a fixed sample geometry is on the order of 1000 dpm 
(i.e. , 1000 dpm/100 cm2). Therefore, taking into consideration the 
practicality of conducting surface contamination surveys; contamination 
control limits should not be set below 5000 dpm/100 cm2 total and 1000 dpm/ 
100 cm2 removable. The ability to detect minute, discrete particle 
contamination depends on the activity level, background, instrument time 
constant, and survey scan speed. A copy of Sommers studies is attached which 
provides useful guidance on establishing a contamination survey program. 

Based on the studies of residual radioactivity limits for decommissioning 
(NUREG-06132 and NUREG-07073), it can be concluded that surfaces uniformly 
contaminated at levels of 5000 dpm/ 100cm2 (beta-gamma activity from nuclear
power reactors) would result in potential doses that total less than 5 
mrem/yr. Therefore, it can be concluded that for the potentially undetected 
contamination of discrete items and materials at levels below 5000 
dpm/100cm2, the potential dose to any individual will be significantly less 
than 5mrem/yr even if the accumulation of numerous items contaminated at 
this level is considered. 

Guidance: 

Items and material should not be removed from the restricted area until they
have been surveyed or evaluated for potential radioactive contamination by a 
qualified* individual. Personal effects (e.g., notebooks and flash lights) 
which are hand carried need not be subjected to the qualified individual 
survey or evaluation, but these items should be subjected to the same survey
requirements as the individual possessing the items. Contaminated or 
radioactive items and materials must be controlled, contained, handled, 
used, and transferred in accordance with applicable regulations. 

The contamination monitoring using portable survey instruments or laboratory
measurements should be performed with instrumentation and techniques (survey
scanning speed, counting times, background radiation levels) necessary to 
detect 5000 dpm/100 cm2 total and 1000 dpm/100 cm2 removable beta/gamma 
contamination. Instruments should be calibrated with radiation sources 
having consistent energy spectrum and instrument response with the 
radionuclides being measured. If alpha contamination is suspected 
appropriate surveys and/or laboratory measurements capable of detecting 100 
dpm/100 cm2 fixed and 20 dpm/100 cm2 removable alpha activity should be 
performed. 


*A qualified individual is defined as a person meeting the radiation 
protection technician qualifications of Regulatory Guide 1.8, Rev. 1, which 
endorses ANSI N18.1, 1971. 
.

                                                            IEC 81-07     
                                                            May 14, 1981  
                                                            Page 3 of 3   

In evaluating the radioactivity on inaccessible surfaces (e.g., pipes, drain
lines, and duct work), measurements at other appropriate access points may 
be used for evaluating contamination provided the contamination levels at 
the accessible locations can be demonstrated to be representative of the 
potential contamination at the inaccessible surfaces. Otherwise, the 
material should not be released for unrestricted use. 

Draft ANSI Standard 13.124 provides useful guidance for evaluating 
radioactive contamination and should be considered when establishing a 
contamination control and radiation survey program. 

No written response to this circular is required. If you have any questions 
regarding this matter, please contact this office. 

                                REFERENCES 

1    Sommers, J. F., "Sensitivity of Portable Beta-Gamma Survey 
     Instruments," Nuclear Safety, Volume 16, No. 4, July-August 1975.

2    U.S. Nuclear Regulatory Commission, "Residual Radioactivity Limits for 
     Decommissioning, Draft Report," Office of Standards Development, USNRC 
     NUREG-0613, October 1979.

3    U.S. Nuclear Regulatory Commission, "A Methodology for Calculating 
     Residual Radioactivity Levels Following Decommissioning," USNRC 
     NUREG-0707, October 1980.

4    Draft ANSI Standard 13.12, "Control of Radioactive Surface 
     Contamination on Materials, Equipment, and Facilities to be Released 
     for Uncontrolled Use," American National Standards Institute, Inc., New 
     York, NY, August 1978.

Attachments: 
1. Reference 1 (Sommers Study) 
2. Recently issued IE Circulars 

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