ML20203E534

Branch Technical Position on When to Remediate Inadvertent Contamination of Terrestrial Environment

ML20203E534
Person / Time
Issue date:	10/31/1994
From:	NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS)
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NUDOCS 9802270074
Download: ML20203E534 (17)

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BRANCH TECHNICAL POSITION ON WHEN TO REMEDIATE INADVERTENT CONTAMINATION OF THE TERRESTRIAL ENVIRONMENT OCTOBER 1994 o/<

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1. INTRODUCTION The U.S. Nuclear Regulatory Commission, Office of Nuclear Material hafety and Safeguards (NMSS), is responsible for re9 lating licensed nuclear material facilities in a manner that will prevent adverse impacts on workers, the public, and the environment, from normal operations and during periods of operational occurrences. Past, present, and future inadvertent releases of radioactive material from tanks, prowss streams, radioactive waste streams, and other sources should be considered operational occurrences or spills. In addition, an inadvertent buildup of radioactive material in the environment from routine releases may also be considered an operational occurrence. As a matter of gaod orU ding practice, licensees +. hat utilize radioactivo material

) might have in place a program to mitigate the consequences of operational occurrences or inadvertent contamination of the terrestrial environment (i.e.,

, ground, groundwater, and surface watar) from radioactive material.

Generally, when an operational occurrence or inadvertent contamination of the terrestrial environment occurs, licensees are required to: a) implement any prepared stabilization and remediation r.lans, as a part of the licensees' operattunal program,10 keep the dose impact to a level that is as low as reasonably achievable (ALARA)(see 10 CFR 20.1101(b)); and b) document the operati m 1 occurrence or inadvertent contamination, and subsequent actions, in accordance with decommissioning recordkeeping requirements. In the absence of a prepared plan, licensees should: a) make a diligent effort to contain the contamination to a small an area as possible; and b) make an assessment of the potential longterm dose impacts of the contamination event en workers 1

and members of the public as soon as possible after the event. The stabilization and remediation plans or actions should address the immediate remediation of contaminated areas that have the potential to allow migration or release of contamination to ar. unrestricted aru. If contamination of an unrestricteo area occurs, the licensee's stabilization and-remediation plans should identify procedures to control access to the area and aodress a process for immediate remediation. l The purposes of this Dranch Technical Position (BTP) are: a) to provide licensees with NHSS staff's expectations for operational good practices, remediation inethods, and procedures following inadvertent contamination of the terrestrial environment by radioactive claterials licensed pursuant to Parts 30, 40, 70, 72, and decommissioning Part 50 licensees; b) to inform licensees of the nature of an NRC response to an inadvertent contamination of the terrestrial environment; and, c) to help insure consistency in NRC responses to instances of inadvertent contamination of the terrestrial environment.

This guidance is also intended to address the timing of remediation (immediate or delayed) of inadvertent contamination of the terrestrial environment. This BTP does not supplant NRC's emergency (contingency) planning or the requirements under the Final Rule for limeliness in Decommissioning of Materials Facilities (NRC,1994).

1.1 Inadvertent Contamination of the Terrestrial Environment An inadvertent contamination of the terrestrial environment is defined for purposes of this BTP, as:

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4 When an unexpected or unmonitored release Of radioactive material, in any physical form, as a result of a spill, leak, or a pouring, pumping, leaching, or discharge of any other sort from any storage device, container or conduit to an area outside of the exterior

walls, floo-s or ceiling of a building or str 'e that results ,

or could result, in contaminated ground, groundwater, or surface-water, This definition does not include radioactive material in effluent releases authorized within the context of NRC regulations, but could include a significant inadvertent buildup of radioactive material in the terrestrial

! environment from authorized releases. This BTP is meant to cover past, present and future inadvertent contamination events.

1.2 Notification and Recordkeepina Reauirements The notification requirements to NRC for events that involve byproduct, source, or special nuclear material are contained in 10 CFR 20.2202, 20.2203, 30.50, 40.60, 50.72, 50.73, 70.50, and 72.74. Notificttion requirements to individuals are contained in 10 CFR 19.13. Recordkeeping requirements for decommissioning are contained in 30.35, 40.36, 50.75, 70.25, and 72.30.

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2. REMEDIATION OF INADVERTENT CONTAMINATION OF THE TERRESTRIAL ENVIRONMENT 2.1 Immediate Remediation i

immediate remediation is defined as the collection, packaging, treatment or removal, for storage or disposal, of contarninated materials (i.e., the radioactive material released, external surfaces and structures, and terrestrial and other materials contaminated as a result of the release) that result from an inadvertent release of radioactive materials. Remediation is considered immediate if it commences at any time within 30 days of the unanticipated contamination event and continues at a reasonable pace until completion. The time limit for completion of the remediation is bounded by the limits described in the Finkl Rule for Timeliness in Decommissioning of Materials facilities (NRC, 1599; which allows for a maximum of 24 months for the completion of the remediation. Remediation is consider.d complete when the contaminated area can be released for unrestricted use. Stabilization measures may be needed at the discovery of the inadvertent contamination until such time as immediate remediation can commence.

Inadvertent contamination of the terrestrial environment by radioactive

' materials in unrestricted areas, or in restricted areas that threaten to migrate to unrestricted areas, require immediate asses; ment per 10 CFR 20.1302. The dose limits for individual members of the public, as defined in 10 CFR 20.1301, Subpart D, " Radiation Dose Limits for Individual Members of the Public" are applicable for inadvertent contamination in unrestricted-areas. if the assessment of the release indicates that doses to individual 4

f members of the public could exceed the limits of 10 CFR 20.1301 then an immediate remediation may be required. There may be justification for remediation (i.e. the ALARA concept) even if applicable dose limits are not exceeded.

2.1.1 Remediation criteria

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NRC will use existing criteria, and/or approved practices, for determining remediation criter.4 for an inadvertent contamination of an unrestricted area or areas owned by the licensee. The current remediation criteria listed below will be applied on a site-specific basis, to ensure that residual contamination levels are ALARA.

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1. Options 1 and 2 of the Branch Technical Position " Disposal or Onsite Storage of Thorium or Uranium from Past '

Operations" (NRC,1981).

2. " Guidelines for Decontamination of Facilities and Equipment prior to Release for Unrestricted Use or lermination of Licenses for Byproduct, Source or Special Nuclear Material" (NRC,1987).

3. " Termination of Operating License for Nuclear Reactors" (NRC,1974), Table 1, for surface contamination of reactor facility structures. Also cobalt-60, cehtum-137, and europium-152 that may exist in concrete, components, C

. l structures, and soil should be removed such thtt the exposure rate is less than 1.28 x 10 8coulomb /kg (5 ,

microroentgen) per hour t hove natural background at 1 meter, with an overall dose objective of 100 microsievert (10 t millirem)peryear.1

4. " National Primary Drinking Water Standards" (EPA,1975). In accordance with " Guidelines for Decontamination of Facilities and Equipment prior to Release for Unrestricted Use or Termination of Licenses for Byproduct, Source or Special Nuclear Material" (NRC,1987), the maximum-contamination levels for radionuclides in public drinking water, as established by the EPA, should be used as reference standards for protection of groundwater and surface wcter resources.

5. " Radiation Dose Guideline for Protection Against Transuranium Elements Present in,the Environment as a Result +

ofUnplannedContamination"(EPA,1977). This document provides guidelines for acceptable levels of transuranium  ;

elements in soil.

In situations where the contamination is in a restricted area, or in,an unrestricted area where the radionuclides of concern-do not have established

' Letter to Stanford University from Office of Nuclear Reactor Regulation, U.S.-Nuclear Regulatory Commission (NRC,1982).

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remediation criteria for contaminated soil or groundwater, the licensee should describe a process to demonstrate ALARA residual contamination levels, to be evaluated b.y NRC staff, by considering potential doses to individuals from exposure to the contaminatiun.

2.1.2 Determinina Potential Individual Doses from Inadvertent Contamination of the Terrestriah Environment i

If there are no applicable remediation criteria for any of the contaminating '

radionuclides, the licensee mcy noed to havo the capability of calculatir.g the potential dose, to an offsite or onsite individual, that could result as a consequence of the contamination. The dose calculated will be used to determine what site specific action should be taken on a case-by-case basis.

To determine the dose to an individual, the licensee may have to do the following:

1. Determine the extent of the contamination (i.e., be able to specify or calculate the contaminant concentration in all contaminated terrestrial media; define the location, size,

and orientation of the contaminated aret; and provide soil or aquifer characteristic information); and,

2. Have available, or obtain values for, site-specific parameters necessary to properly focus the dose evaluation.

Dose r tlations are needed ); part to determine if any remediation is needed

- and/or to determine the timing of delayed remediation. -Guidance related to 7

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determining which site-specific parameters are important for a given site and on how to determine the potential dose from contaminated terrestrial media can i be found in the following references:

1. "A Manual for Implementing Residual Radioactive Material Guidelines" (00E,1989), and " Data Collection Handbook to Support Modeling the Impacts of Radioactive Materials in Soil" (ANL, 1993).

2. " Residual Radioactive Contamination from Decommissioning:

Volume 1, Technical Basis for Translating Contamination Levels to Annual Total Effective Dose Equivalent" (NRC, 1992a).

3. " Risk Assessment Guidance for Superfund, Volume I, Human Health Evaluation Manual (Part A)" (EPA,1989).

2.1.3 Activities Related to Immediate Remediation ,

As a minimum, the following actions, individually or in combination, should be evaluated as appropriate measures that can be used to mitigate or initially stabilize the consequences of inadvertent contamination of the terrestrial environment by radioactive materials. The actions listed below are not all-inclusive, and additional actions may be required. Actions may be required whenever there is a contaminated terrestrial media that exceeds existing decommissioning criteria for surface soil or groundwater contamination.

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1. Construct drainage controls in order to capture run-off and reduce migration of contaminants. Drainage controls can -

also be used to reduce migration by routing run-on, due to precipitation and flooding, around contaminated areas.

2. Where applicable, use non-hazardous chemicals and other materials to retard the spread of, or mitigate the effects of, an inadvertent contamination event, s

3. Stabilize leaking berms, dikes, impoundments, and lagoons to minimize the volume of contaminated water or other material.

4. Cap contaminated soils, to reduce migration of contaminants.

5. Excavate and remove contaminated materials from drainage ways, utility trenches, and other areas where such actions will reduce the sprcad of-contamination, or reduce the exposure to direct radiation.

6. Contain, treat, package, and dispose of contaminated materials, to reduce the likelihood of exposure to individuals.

7. Install fences, other security devices, warning signs, and establish site control procedures, es required by 10 CFR Part 20, to control access to the area affected by the i

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inadvertent release.

When it is determined that contamination of groundwater has occurred, recovery wells and/or slurry walls may need to be installed. Guidance related to the installation of recovery wells and slurry walls can be found in " Mitigative Techniques for Ground-Water Contamination Associated with Severe Nuclear Accidents" (NRC, 1985). In cases where there is an inadvertent contamination of a body of water or aquifer that could adversely impact the water supply of individual members of the public, that is, exceed the limits in the " National Primary Drinking Water Regulations" (EPA,1976), pro'visio'ns for an alternative '

water supply may be required.

2.2 Delayed Remediation In Restricted Areas Restricted areas are defined as areas, designated by the licensee, with limited access, for the purpose of protecting individuals against undue risks from exposure to radiation and radioactive materials. Good operating practices dictete that, even in restricted areas, inadvertent contamination of terrestrial environments be immediately remediated. However, after the contamination is_ initially stabilized and contained in the restricted area, if it can be shown by the licensee, through an ALARA analysis, that immediate remediation would adversely affect the safety of operations, then remediation can be delayed if the dose limits in 10 CFR 20.1201, Subpart C " Occupational Dose Limits" are not, or would not be, exceeded. The licensee would have to request an extension of time pursuant to the terms of the Timeliness in Decommissioning of Materials facilities regulations (NRC,1994) if it is 10

expected that the delay will cause the remediation of the contamination to occur after 24 months from the date of the discovery of the inadvertent contamination event.

Because most licensees are not authorized to store radioactive materials in the earth onsite, a license amendment might be required to delay remediation and would only be applicable until decommissioning. Also, as stated above, the license is required to document u:. usual occurrences and spills of licensed material per 10 CFR 30.35, 40.36, 50.75, 70.25, and 72.30, whether or not remediation occurred, to facilitete review or revision of the licensee's Decommissioning Plan at the time of final decommissioning.

2.2.1 Activities Related to Delayed Remediation To delay remediation a license amendment, and an exception to the timeliness in decommissioning of materials facilities regulations, might be required, provided that the following conditionr are met:

1. The licensee must make a determination that the volume of contamiacted soil or other material will not become so large, due to migration of contar.ination before site decommissioning, as to make future remediation impractical.

Also, the licensee will have to evaluate, over the like'1y duration of the license, the potential for migration of the contamination to pose an unacceptable risk to public health and safety, 11

2. The licensee will have to initiate an environmental monitoring program, to further enscre that the contamination  ;

is not adversely migrating during the operating period before site decommissioning.

If any of these conditions cannot be met, then remediation of the release should take place immediata.ly. The licensee should also reevaluate the total quantity of material possessed, as a consequence of the inadvertent release, to determine if the new quantity is still within the limits defined in the license. Ibthe newly built-up quantity surpasses the licensed amount, then a license amendment for that will also be needed.

2.2.2 Site Characterization and Environmental Monitorina To establish the contamination migration potential and environmental monitoring programs mentioned above, a site characterization may be required.

Details of site characterization and environmental monitoring programs are specific to a given release situation and site. Guidance on sita characterization and environmental monitoring can be found i.n the following sources:

Sit.g Characterization

1. " Guidance for Conducting Ronedial Investigations and Feasibility Studies under CCRCLA' fEPA, 1988).

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2. " Manual for Conducting Radiological Surveys in Support of License Termination, Draft Report for Comment" (NRC, 1992b).

3. " Draft Branch Technical Position of Site Characterization for Decommissioning Sites" (NRC, 1992c).

Environmental Monitorina

1. "A Guide for: Environmental Radiological Surveillance at U.S. Department of Energy Installations" (DOE,1981).

2. "kCRA Ground-Water Monitoring Technical Enforcement Guidance Document" (EPA, 1986).

3. " Quality Assurance for Radiological Monitoring Programs (Normal Operations) - Effluent Streams and the Environment"

, (NRC,1979).

4. " Recommendation to the NRC for Review Criteria for Alternative Methods of Low-Level Radioactive Waste Disposal" l (NRC,1988).

5. " Environmental Monitoring of low-level Radioactive Waste Disposal Facility" (NRC, 1989).

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2.2.4 Decommissionina Fundina Plan and Recordkeepina Uodates An update of the decommissioning funding plan (DFP) should be made when the licensee seeks approval, by lictnse amendmcat, for delayed remediation. The updated DFP should conrider the extent and nature of the contaminated area, as determined by characterization and environmental monitoring, when developing updated costs for decommissioning. Any further significant change in the nature and/or extent of the contaminated area, over time, requires a revision of the DFP to account for potential increased costs of decommissioning.

4 Recordkeeping, that documents unusual occurrences and spills of licensed material per 10 CFR 30.35, 40.36, 50.75, 70.25, and 72.30, whether or not remediation occurred, is required to facilitate the review or revision of the licensee's Decommissioning Plan at the time of final decommissioning.

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3. REFERENCES ANL, 1993 . Argonne National Laboratory, " Data Collection Handbook to Support Modeling the Impacts of Radioactive Materials in Soil." ANL/EAIS-8, 1993.

DOE, 1981 U.S. Department of Energy, "A Guide For: Environmental Radiological Surveillance at U.S. Department of Energy Installations." DOE /EP-0023,1981.

t DOE, 1989 U.S. Department of Energy, "A Manual for Implementing Residual Radioactive Material Guidelines." DOE /CH/8901, 1989.

EPA, 1976 U.S. Environmental Protection Agency, "Part 141 - Interim Primary Drinking Water Regulations, Promulgation of Regulations on Radionuclides." 41 B 28402, July 9, 1976.

EPA, 1977 U.S. Environmental Protection Agency, " Radiation Dose Guideline for Protection against Transuranium Elements Present in the Environment as a Result of Unplanned Contamination." 42 B 60956,

, November 30, 1977.

EPA, 1986 U.S. Environmental Protection Agency, apr.RA Ground-Water Monitoring Technical Enforcement Guidance Document." OSWER-9950.1, 1986.

EPA, 1988 U.S. Environmental Protection Agency, " Guidance for Conducting Remedial Investigations and Feasibility Studies Under CERCLA.

EPA /540/G-84/004,1988.

EPA, 1989 U.S. Environmental Protection Agency, " Risk Assessment ruidance for Superfund, Volume I, Human Health Evaluation Manual (Part A)."

EPA /540/1-89/002,1989.

NRC, 1974 U.S. Nuclear Regulatory Commission, " Termination of Operating Licenses for Nuclear Reactors." Regulatory Guide 1.86, 1974. ,

NRC, 1979 U.S. Nuclear Regulatory Comission, " Quality Assurance for Radiological Monitoring Programs (Normal Operations) - Effluent Streams and the Environment." Regulatory Guide 4.15,19E NRC, 1981 'J.S. Nuclear Regulatory Comission, " Disposal or Onsite Storage of Thorium or Uranium from Pa:t Operations." 46 8 52061,' October 23, 1981.

NRC, 1982 U.S. Nuclear Regulatory Commission, Letter to Stanford University from James R. Miller, Chief, Standardization and Special Projects, Division of Licensing, Office of Nuclear Reactor Regulation, U.S.

Nuclear Regulatory Commission (Docket No. 50-141), April 21,1982.

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NRC, 1985 U.S. Nuclear Regulatory Commission, " Mitigative Techniques for Ground-Water Contamination Associated With Severe Nuclear Accidents." NUREG/CR-4251,1985.

NRC, 1987 U.S. Nuclear Regulatory Commission, " Guidelines for Decontamination of Facilities and Equipment prior to Release for Unrestricted Use or Termination of License for Byp oduct Source or Special Nuclear Material." Policy and Guidance Jirective FC-83-23, Division of Industrial and Medical Nucl. ear Safety, August 1987.

NRC, 1988 U.S. Nuclear Regulatory Commission, " Recommendations to the NRC for Review Criteria for Alternative Methods of low-Level Radioactive Waste Disposal." NUREG/CR-5054, 1988.

NRC, 1989 U.S. Nuclear Regulatory Commission, " avironmental Monitoring of Low-level Radioactive Waste Di,posal Facility." NUREG-1388, 1989.

NRC, 19? a U.S. Nuclear Regulatory Commission, " Residual Radioactive Contamination from Decommissioning: Volume 1 Technical Basis for Translating Contamination Levels to Annual Total Effective Dose Equivalent." NUREG/CR-5512,1992.

NRC, 1992b U.S. Nuclear Regulatory Commission, " Manual for Conducting Radiological Surveys in Support of License Termination, Draft Report for Comment." NUREG/CR-5849,1992.

NRC, 1992c U.S. Nuclear Regulatory Commission, " Draft Branch Technical Position of Site Characterization for Decommissioning Sites."

(1992)(Unpublished).

NRC, 1994 U.S. Nuclear Regulatory Commission, " Timeliness in Decommissioning of Materials Facilities." 59 fB 36026, July 15,1994.

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