United States Nuclear Regulatory Commission - Protecting People and the Environment

On-Site Storage of Low-Level Waste (Generic Letter 80-51)



GL80051 

                               UNITED STATES 
                       NUCLEAR REGULATORY COMMISSION 
                          WASHINGTON, D. C. 20555 

                                JUNE 9 1990 

MEMORANDUM FOR:     T. Novak, Assistant Director for Operating Reactors, DL 
                    R. Tedesco, Assistant Director for Licensing, DL 
                    G. Lainas, Assistant Director for Safety Assessment, DL 

FROM:               D. G. Eisenhut, Director, Division of Licensing 

SUBJECT:            LETTER TO LICENSEES CONCERNING ON-SITE STORAGE OF   
                    LOW-LEVEL WASTE 

The attached letters which has concurrence from the appropriate 
organizational entities in the new NRR organization, should be sent to all 
power reactors by each Operating Reactors Branch and the Licensing Branches 
for Sequoyah, Salem 2, and North Anna 2 within the five working days. 


                                        D. G. Eisenhut, Director 
                                        Division of Licensing 

Enclosure:
As stated 

cc w/enclosure:
B. Snyder 
H. Denton 
V. Stello 
E. Case 
R. Minogue
D. Ross 
T. Murphy 
B. Grimes 
V. Malafeew
R. Bangart
DOL BCs  
R. Weller 
S. Bland 
G. Bidinger 
J. Martin 
P. Psmas 
R. Browning 
P. Wagner 
D. Smith 
B. Singer 
R. Ryan 

Contact: P. Grant, X28066 
.

                              UNITED STATES 
                       NUCLEAR REGULATORY COMMISSION 
                          WASHINGTON, D. C. 20555 

LETTER TO:  ALL POWER REACTOR LICENSEES 

SUBJECT: TEMPORARY ON-SITE STORAGE OF LOW LEVEL RADIOACTIVE WASTE 

Recent restrictions and reduced allocations at commercial burial sites have 
caused numerous Licensees to actively consider increased on-site storage. 
Several Licensees are currently storing waste on a temporary basis and 
proposing to establish new facilities for longer term storage. If on-site 
storage is necessary, the Licensee must assure that the design and operation
of the proposed facilities are adequate to maintain public health and 
safety, minimal risk to operating personnel, and present a minimal 
environmental impact. 

Any decision to incorporate on-site storage requires a 10 CFR 50.59 safety 
review of the areas of (1) Radioactive Material and Effluent Control, (2) 
Radiation Dose Control for both on-site and off-site individuals, and (3) 
Accident Prevention and Control. Enclosed is a draft NRC Licensing Position 
for "Safety Considerations for Temporary On-Site Storage." This draft is 
forwarded for your information and use in evaluating low-level waste (LLW) 
storage criteria. 

The NRC is presently evaluating both temporary and long term on-site storage
and its implications. Currently, 10 CFR 50.59 requires that you furnish a 
report containing a brief description and summary of the safety evaluation 
for each 10 CFR 50.59 change to your facility. The proposed model Appendix I 
generic technical specifications (NUREG 0472 and 0473) contained guidance on 
the desired detail necessary in that report for radwaste system. In the 
interim, until Appendix I technical specifications are incorporated in your 
operating license, you are requested to include reviews for on-site storage 
additions in the monthly operating report following the period in which the 
evaluation was completed. This report should detail the major 
additions/changes and contain a summary of the safety evaluation. This 
summary should include as a minimum your evaluation of each of the safety 
review areas described herein, including consideration of the guidance 
provided in the enclosed draft Licensing Position, man-rem impacts 
anticipated radiological release assessments, final disposition of waste, 
and final conclusion of the 50.59 evaluation. 
.

                                  - 2 -

No formal response is required concerning this letter unless waste storage 
facilities are modified. Comments however, are invited concerning the 
enclosed draft Licensing position. 


                                        Branch Chief 
                                        Operating Reactors Branch # 
                                        Division of Licensing 

Enclosure:
As stated 
.

                              UNITED STATES 
                       NUCLEAR REGULATORY COMMISSION 
                          WASHINGTON, D. C. 20555 

SAFETY CONSIDERATION FOR TEMPORARY ON-SITE STORAGE OF LOW LEVEL RADIOACTIVE 
WASTE 

I.   Introduction 

     The objective of this technical position is to provide guidance to the 
     Licensees considering additional on-site low level radioactive waste 
     storage capabilities. The duration of the intended storage, the type 
     and form of waste, and the magnitude of radionuclides present will 
     dictate the safeguards and the level of complexity required to assure 
     public health and safety, and minimal risk to operating personnel. The 
     longer the intended storage period, the greater the degree of controls 
     that will be required for radiation protection and accident prevention. 
     For purposes of this document, the duration of temporary material 
     storage is to be up to four (4) years. The magnitude of the on-site 
     storage safety hazard is predicated on the type of waste being stored, 
     the amount of radionuclides present, and how readily they might be 
     transported into the environment. In general, it is preferable to start
     radioactive material in solid form. Under some circumstances, however, 
     temporary storage in a liquid form may be desirable or required. The 
     specific design and operation of any storage facility will be 
     significantly influenced by the various waste forms, consequently, this
     document addresses wet waste, solidified wet waste and dry low level 
     radioactive waste. 
     
II.  General Information 

     Prior to any implementation of additional on-site storage, substantial 
     safety reviews and environmental analysis need to be conducted to 
     assure adequate public health and safety, and minimal environmental 
     impact. The acceptance criteria and performance objectives of any 
     proposed storage facility, or area, will need to meet minimal 
     requirements in areas of design considerations operational 
     considerations, safety considerations and policy considerations. For 
     purposes of this branch position the major emphasis will be on safety 
     considerations in the storing, handling and eventual disposition of the 
     radioactive waste. Design and operational acceptability will be based 
     on minimal requirements which are defined in existing SRP's, Regulatory 
     Guides, and industry standards for proper management of radioactive 
     waste. Policy considerations for waste minimization and volume 
     reduction will also have to be integrated into the waste management 
     plan and the on-site storage alternative. Additional considerations for 
     ALARA, decontamination, and decommissioning of the temporary storage 
     facility also need to be integrated into the design and operation of 
     the proposed waste storage facility. Integration of waste 
.

                                  - 2 -

     volume reduction and eventual disposal should be performed as early as 
     possible because future requirements for waste forms may make stored 
     wastes unacceptable for final disposition. 

III. Wet Radioactive Waste Storage 

     (a)  Wet radioactive waste will be defined as nay liquid or 
          liquid/solid slurry. for storage considerations, we waste is 
          further defined as any waste which does not meet January 1, 1981 
          burial requirements for solidified waste (i.e, < 0.5% free water 
          by volume of container or < 1.0 gallon per container whichever is 
          less). 
          
     (b)  The facility, supporting structure and tanks should be designed to
          prevent uncontrolled releases of radioactive materials due to 
          spillage or accident conditions. 

     (c)  The following design objectives and criteria are applicable for 
          wet radioactive waste facilities. 

          (1)  Structures that house liquid radwaste storage tanks should be
               designed to seismic criteria as defined in Standard Review 
               Plan (NUREG 75087) - Section 11.2). Foundations and walls 
               shall also be designed and fabricated to contain the liquid 
               inventory which might be released during a container/tank 
               failure. 

          (2)  All tanks or containers should be designed to withstand the 
               corrosive nature of the wet waste stored. The duration of 
               storage under which the corrosive conditions exist shall also
               be considered in the design. 

          (3)  All storage structures should have curbs or elevated 
               thresholds with floor drains and sumps to safely collect wet 
               waste assuming the failure of all tanks or containers. 
               Provisions should be incorporated to route spilled wet waste 
               to the radwaste treatment systems. 

          (4)  All tanks and containers shall have provisions to monitor 
               liquid levels and to alarm potential overflow conditions. 

          (5)  The quantity of radioactive material allowed and the 
               shielding configurations will be dictated by the dose rate 
               criteria for both the site boundary and unrestricted areas 
               on-site. The 40 CFR 190 limits will restrict the annual dose 
               from direct radiation and effluent release to the Public 
               (individual) to less than 25 mrem per year to the whole body 
               from all sources of the Uranium fuel clycle; therefore, 
               off-site doses from on-site 
.

                                  - 3 -

               storage must be sufficiently low to account for other sources
               (e.g., < 1 mrem/year). On-site dose limits associated with 
               temporary storage will controlled per 10 CFR Part 20 
               including the ALARA principle of 10 CFR 20.1. 

          (6)  All potential release pathways of radionuclides (e.g., 
               evolved gases breach of container, etc.) shall be controlled 
               and, monitored as per 10 CFR 50 Appendix A (General Design 
               Criteria 60 and 64). Surveillance programs should incorporate 
               adequate methods for monitoring breach of container integrity 
               or accidental releases. 
               
          (7)  All temporarily stored wet waste will require additional 
               reprocessing prior to shipment off-site; therefore, provision
               should be established to integrate the required treatment 
               with the waste processing and solidification systems. The 
               interface and associated systems should be designed and 
               tested in accordance with the codes and standards described 
               in NUREG-75/087 Section 11 
               
IV.  Solidified Radioactive Waste Storage 

     (a)  Solidified radwaste for storage purposes shall be defined as that 
          waste which meets January 1, 1981 burial site solidified waste 
          criteria. Therefore, solidified radwaste will be identified as wet
          waste (e.g., evaporation bottoms, resins, and sludge) which is 
          solidified and contains < 0.5% free water (by container volume) or
          1.0 gallon of liquid (in the container), whichever is less. For 
          purposes of this document resins or filter sludges dewatered to 
          the above criteria will be defined under this waste 
          classification/criteria. 

     (b)  Dewatered resins and filter media with radioactivity levels above 
          1 uCi/cc (>5 yr, half-life) which are disposed of a after July 19 
          1981, will be required to be solidified or stored in high 
          integrity, containers (e.g. reinforced concrete) Any storage 
          plans, should address container protection as well as reprocessing 
          requirements for eventual shipment & burial. 

     (c)  Cask, tanks, and liners containing solidified radioactive waste 
          should be designed with good engineering judgment to preclude or 
          reduce the occurrence of uncontrolled releases of radioactive 
          materials due to handling, transporting or storage. Accident 
          mitigation and control for design basis events (e.g., fire, 
          flooding, tornadoes, etc.) must be evaluated and protected against
          unless otherwise justified. 
.

                                   -4-

     (d)  The following objectives and criteria are applicable for 
          solidified waste storage containers and facilities: 

          (1)  All solidified radwaste should be located in restricted areas
               where effective material control accountability can be 
               maintained. While structures are not required to meet seismic
               criteria, protection should be afforded to insure the 
               radioactivity is contained safely by use good engineering 
               judgment, such as the use of curbs and drains to contain 
               spills of dewatered resins or sludges. 

          (2)  Container material selection should conform to requirements 
               established in NUREG-75/087 (Section 11). If liquids exist 
               which are corrosive, proven provisions should be made to 
               protect the container (i.e., special liners or coatings) and,
               or neutralize the excess liquids. If deemed appropriate and 
               necessary, highly non-corrosive materials (e.g., stainless 
               steel) should be use. Potential corrosion between the solid 
               waste forms and the container should also be considered. In 
               the case of dewatered resins, highly corrosive acids and 
               bases can be generated which will significantly reduce the 
               longevity of the container. The Process Control Program 
               (PCP), should implement steps to assure the above does not 
               occur, and provisions on container material selection and 
               precoating should implement steps to assure the above does 
               not occur, and provisions on container material selection and 
               precoating should be made to insure that container breach 
               does not occur during temporary storage periods. 
               
          (3)  Potential release pathways of all radionuclides present in 
               the solidified waste form shall be monitored as per 10 CFR 50
               Appendix A. Surveillance programs shall incorporate adequate 
               methods for detecting failure or container integrity and 
               measuring releases to the environment. For outside storage, 
               periodic direct radiation and surface contamination 
               monitoring shall be conducted to insure that levels are below 
               limits specified in 10 CFR 20.202, 20.205, and 49 CFR 
               173.397. All containers should be decontaminated to these 
               levels or below before storage. 
               
          (4)  Provision should be made for additional reprocessing or 
               repackaging due to container failure and/or, as required for 
               final transportation and burial as per DOT and burial site 
               criteria. Contamination isolation and decontamination 
               capabilities should be developed. Whereby significant 
               handling personnel exposure can be anticipated, ALARA method 
               should be incorporated as per Regulatory Guides 3.8 and 8.10. 
.

                                   -5-

          (5)  Procedures should be developed and implemented for early 
               detection, prevention and mitigation of accidents (e.g., 
               fires). Storage areas and facility designs should incorporate
               good engineering features and contingencies so as to handle 
               accidents and provide safeguard systems such as fire 
               detectors and suppression systems, (e.g., smoke detector and 
               sprinklers), personnel training and administrative procedures
               to insure both control of radioactive materials and minimum 
               personnel exposures. Fire suppression devices may not be 
               necessary if combustible materials are minimal in the area. 

          (6)  Provisions should be incorporated for collecting liquid 
               drainage including provisions for sampling all collected 
               liquids. Routine of the collected liquids should be to 
               radwaste systems of contamination is detected or to normal 
               discharge pathways if the water ingress was from external 
               sources and remained uncontaminated 

          (7)  Low level solidified waste stored in outside areas should be 
               held securely by installed hold down systems. The hold down 
               system should secure all containers during severe 
               environmental conditions up to and including the design basis
               event for this waste storage facility. 

          (8)  Container integrity should be assured against corrosion from 
               the external environment; external weather protection should 
               be included where necessary and practical storage containers 
               should be raised off storage pads where water accumulation 
               can be expected to cause external corrosion and possible 
               degradation of container integrity. 

          (9)  The quantity of radioactive material allowed and the 
               shielding configurations will be dictated by the dose rate 
               criteria for both the site boundary and unrestricted arts 
               on-site. The 40 CFR 190 limits will restrict the annual dose 
               from direct radiation and effluent releases to the Public 
               (individual) to less than 25 mrem per year to the whole body 
               from all sources of the Uranium fuel cycle; therefore, 
               off-site doses from on-site storage must be sufficiently low 
               to account for other sources (e.g., < 1 mrem/year). On-site 
               dose limits associated to temporary storage will be 
               controlled per 10 CFR Part 20 including the ALARA principle 
               of 10 CFR 20.1. 
.

                                   -6-

          (10) Total curie limits should be established based on the design 
               of the storage area and the safety features provided 

          (11) Inventory records of waste types, contents, dates of storage,
               shipment, etc., should be maintained 

V.   Low Level Dry Waste Storage 

     (a)  Low level dry waste is classified as contaminated material (e.g., 
          paper, trash, air filters) which contains sources of radioactive 
          material that is dispersed in small concentrations throughout 
          large volumes of inert material which contain no free water. 
          Generally, this consists of dry material such as rags, clothing, 
          contaminated materials and small equipment (i.e., tools and 
          instruments) which cannot be easily decontaminated 
          
     (b)  Licensees should implement controls to segregate and minimize the 
          generation of Low Level Dry Waste to lessen the impact on waste 
          storage. Integration of Volume Reduction (VR) hardware should be 
          considered to minimize the need for additional waste storage 
          facilities. 

     (c)  The following design objectives are criteria are applicable for 
          low level dry waste storage containers and facilities. 

          (1)  All dry or compacted radwaste should be located in restricted
               areas where effective material control and accountability can
               be maintained. While structures are not required to meet 
               seismic criteria, protection should be afforded to insure the
               radioactivity is contained safely by use of good engineering 
               judgment 

          (2)  The waste container should be designed to insure radioactive 
               material containment during normal and abnormal occurrences. 
               The waste container materials should not support combustion. 
               The packaged material should not cause fires through, 
               spontaneous chemical reactions, retained heat, etc. 

          (3)  Potential release pathways of all radionuclides present in 
               the solidified waste form shall be monitored as per 10 CFR 50
               Appendix A. Surveillance programs shall incorporate adequate 
               methods for detecting failure of container integrity and 
               measuring releases to the environment. For outside storage 
               periodic direct radiation and surface contamination 
               monitoring shall be conducted to insure that levels are below 
               limits specific in 10 CFR 20.2029 20.2051 and 49 CFR 173.397. 
               All containers should be decontaminated to these levels ar 
               below before storage 
.

                                   -7-

          (4)  containers should generally comply with the criteria of 10 
               CFR 71 and 4 CFR 170 to minimize the need for repackaging for 
               shipment. 

          (5)  Increased container handling and personnel exposure can be 
               anticipated, consequently, all ALARA methodology should be 
               incorporated per Regulatory Guide 8.8 and 8.10. 

          (6)  The quantity of radioactive material allowed and the 
               shielding configurations will be dictated by the dose rate 
               criteria for both the site boundary and unrestricted areas 
               on-site. The 40.CFR 190 limits will restrict the annual dose 
               from direct radiation and effluent release to the Public 
               (individual) to less than 25 mrem per year to the whole body 
               from all sources of the Uranium fuel cycle; therefore, 
               off-site doses from on=site storage must be sufficiently low 
               to account for other sources (e.g., <1 mrem/year). On-site 
               dose limits associated to temporary storage will be 
               controlled per 10 CFR Part 20 including the ALARA principle 
               of 10 CFR 20.1. 
               
          (7)  Total curie limits should be established based on the design 
               of the storage area and the safety features provided. 

          (8)  Provisions should be incorporated for collecting liquid 
               drainage including provisions for sampling all collected 
               liquids. Routing of the collected liquids should be to 
               radwaste systems if contamination is detected or to normal 
               discharge pathways if the water ingress was from external 
               sources (e.g, rain water or moisture) and remained 
               uncontaminated. 

          (9)  Low-level waste stored in outside areas should be held 
               securely by installed hold down systems. The hold down system
               should secure all containers during severe environmental 
               conditions up to and including the design basis event for 
               this waste storage facility. 

          (10) Container corrosion should be assured against from both the 
               internal and external environment. Special internal liners 
               and external weather protection should be included where 
               necessary and practical. Storage containers should be raised 
               off storage pads where water accumulation can cause external 
               corrosion and resultant loss of container integrity. 

          (11) Inventory records of waste types, contents, dates of storage,
               shipment, etc., should be maintained. 

Page Last Reviewed/Updated Monday, June 17, 2013