ML20052A083
| ML20052A083 | |
| Person / Time | |
|---|---|
| Issue date: | 03/31/1982 |
| From: | Rich Smith NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | AFFILIATION NOT ASSIGNED |
| References | |
| FRN-46FR38081, REF-WM-4, RULE-PR-61 NUDOCS 8204270054 | |
| Download: ML20052A083 (15) | |
Text
PR-4 I DISTRIBUTION (A FM Md MAR 31 NR in.L es/fd (lum-- h
[WMLL7/f NMSS r/f 202/GWR/_82/3/18/0 WM r/f GWRoles Nehrd PHLohaus RDSmith fjf/-jM REBrowning g gf WitLL: 202 JBMartin PDA
Dear Sir:
Table 1 of Section 61.55 of the proposed regulation 10 CFR Part 61 includes a classification system which defines, based upon concentrations of particular radionuclides, requirements for near-surface disposal of radioactive waste. A number of comments from the public have been received on this classification system, including
' comments on some of the specific numerical values in Table 1 as well as coments on the need for guidance on acceptable procedures for determining proper waste classes. The numerical values in Table 1 ar being reexamined in light of the comments and there may be chang p
W to some of the the values in the final Part 61 regulation. To
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waste generators guidance on determining proper waste classes e are 29 preparing a branch technical position (BTP) on waste classif ationy,(RF, o[ t which outlines generally acceptable procedures for measurin pd ?F4 p'e# _3 7
reporting radioactivity in various waste streams. A copy of pgy C
preliminary draft of this BTP is enclosed.
p% g As currently written, a general outline of acceptable licensee "by.
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e programs to assure compliance with the waste classification recidifeme
,s is presented in the body of the BTP, while acceptable programs sii d ci V to particular licensees would be presented in appendices to the BTP.
The preliminary draft BTP contains an appendix which discusses a three tiered approach for measuring and reporting radioactivity in wastes from light water cooled nuclear power plants. Similar appendices for other waste generators may be developed for future drafts.
The enclosed preliminary draft BTP needs additional work but we are sending it to you at this time for your early review and comment.
Through this process of early review and comment by interested parties -
such as yourself, we hope to be able to consider your and others ideas and views upon the BTP intrinsically as part of its development. We believe that this process will hasten the finalization of the BTP so that it is workable and practical to those who must use it.
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9AR31199 202/GWR/82/3/18/1 i We would' therefore appreciate your review and comment on this preliminary draft BTP regarding the overall approach taken as well as any specific comments you may have.
In particular, we would appreciate
.your input with respect to the following:
- The acceptability of using the outlined three tiered measurement system for nuclear power plant wastes;
- Practical ways in which the number of actual analyses can be minimized (e.g., using process controls'to ensure consistent waste concentrations); and
- Based upon your knowledge and practical experience, the ability to measure and quantify (and limits of error) the radionuclides set forth in. Table 1, Section 61.55, of the proposed Part 61 regulation.
In addition, any data that you may have and want to volunteer on the actual concentrations of the radionuclides listed in Table 1 in specific waste streams would be appreciated. We would appreciate your comments by April 30, 1982.
If you have any questions regarding this draft BTP, please contact either myself at (301) 427-4433 or Mr. G. W. Roles at (301) 427 4593.
Original Signed By R. Dale Smith, Chief.
Low-Level Waste Licensing Branch Division of Waste llanagement DIST:
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_ _ _ _ _ : _ _ _ _ _ _ _ _ _'/_ j n f//82 DATE_:82/03/30~
- 3/30/82 3/*p/82
1 DRAFT BRANCH TECHNICAL POSITION ON RADI0 ACTIVE WASTE CLASSIFICATION i
A.
Introduction Section 20.311 (" Transfer for disposal and manifests") of 10 CFR Part 20 (" Standards for Protection Against Rad,iation") requires that any licensee who transfers radioactive waste to a land disposal facility or to a licensed waste collector or processor must classify the waste according to Section 61.55 (" Waste Classification") of 10 CFR Part 61
(" Licensing Requirements for Land Disposal of Radioactive Waste").
Section 20.311 also requires that any licensed waste processor who treats or repackages radioactive waste for disposal into a land disposal facility also classify their waste according to Section 61.55.
Section 61.55 defines radioactive waste suitable for land disposal as falling into one of three categories--i.e., Class A segregated waste, Cless B stable waste, and Class C intruder protected waste.
Wastes are determined to fall into one of the classes by comparison to limiting concentrations of particular radionuclides which are set forth in Table 1 to Section 61.55.
Wastes determined to fall into one of the classes must be labeled as such in accordance with Section 61.57 (" Labeling").
Waste generators and waste processors must record the concentrations of the radionuclides in Table 1 on shipment mar.ifests, and must also carry out a quality assurance program to assure that classification of waste is carried out in a proper manner.
All three classes of waste are required to meet certain minimum requirements as set forth in paragraph 61.56 (a) of Section 61.56 (" Waste Characteristics") which are intended to facilitate handling of waste at the disposal site and provide protection of public health and safety.
Class B and Class C wastes, however, are required to meet mor' rigorous requirements on waste stability.
These stability requirements are set forth in paragraph 61.56(b) to Section 61.56.
Class C waste must be also identified to allow for additional disposal procedures to be carried out at the disposal site to provide protection to a potential inadvertent
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2 intruder.
Finally, wastes having concentrations of particular radionuclides exceeding those allowed for Class C waste are generally considered unacceptable for near-surface disposal.
This branch technical position describes overall procedures acceptable to the Regulatory Staff which may be used by licensees to determine the presence and concentrations of radionuclides listed in Table 1, and thereby classifying waste for near-surface disposal.
B.
Discussion Each shipment of radioactive waste by a waste generator to a licensed collector, processor, or operator of a land disposal facility must ensure that a shipment manifest accompany the waste.
The manifest must include information on waste characteristics including the type of waste (e.g., solidified resins, trash), the waste volume and mass, the radionuclide identity and concentration, the total radioactivity, the chemical form, the solidification agent (if any), and the waste class.
As part of this, the total quantity of the particular radionuclides listed on Table 1 of Section 61.55 must be listed These radionuclides A
This should be the principal chemical form that the radioactivity is contained in -- e.g., calcium fluoride, toluene, etc.
As part of this, the presence of hazardous chemicals as defined by EPA should be noted.
AA Radionuclides not specifically listed in Table 1 and forming a significant part of the total radioactivity should also be listed for j
purposes of waste handling and transportation safety.
Radionuclides not 4
specifically listed in Table 1 and not forming a significant part of the total radioactivity (particularly those having half lives less than 5 years) need not be listed.
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are used to determine the classification status of radioactive waste.
Controlled disposal of wastes containing these radionuclides is considered important in assuring that the performance objectives of Subpart C of the Part 61 regulation are met.
To classify waste for disposal and fill out shipment manifests, a licensee must make two basic determinations:
(1) whether the waste is acceptable for near-surface disposal, and (2) if acceptable for near-surface disposal, whether the waste is classified as Class A, Class B, or Class C waste.
Waste is determined to be generally unacceptable.for near-surface disposal if it contains any of the radionuclides listed in column 3 of Table 1 of Section 61.55 in concentrations exceeding the limits established for the radionuclides.
If determined to be acceptable for near surface disposal, waste is determined to be Class A, Class B, or Class C based upon the list of radionuclide concentrations limits set forth in columns 1 and 2 of Table 1.
(Note that the concentration limits in Table 1 may be subject to change.)
C.
Regulatory Position All licensees must carry out a compliance program to assure proper classification of waste.
Licensee programs to determine radionuclide concentrations and waste classes may, depending upon the particular operations at the licensee's facility, range from simple programs to very complex ones. There are four basic programs, however, which may be potentially used either individually or in combination by licensees:
- materials accountability;
- classification by source,
- gross radioactivity measurements; or
- direct measurement of individual radionuclides.
4 The following discussion outlines instances and conditions whereby each basic program or combinations thereof would be acceptable to regulatory staff to demonstratt Mmpliance with the waste classification requirement.
A licensee's program should be specific to a particular facility, and should consider the different radiological and other characteristics of the different waste streams generated by the facility.
A general criteria for acceptability of a particular program established to comply with the waste classification requirement is that the measured or inferred concentrations of the radionuclides listed in Table 1 of Section 61.55 are accurate in each waste stream generated to within a factor of 10.
In general, more sophisticated programs wo'ld be required for u
licensees generating Class B or Class C waste, for licensees generating waste for which minor process variations may cause a change in classification, or for licensees generating waste for which there is a reasonable possibility of the waste containing concentrations of radionuclides which exceed limiting concentration limits for near-surface disposal.
Some licensees, such as nuclear power facilities, are expected to employ a combination of methods.
Appendix A to this BTP outlines an example program for nuclear power facilities which the regulatory staff would find acceptable.
1.
General Criteria a.
Compliance Through Materials Accountability One method which the regulatory staff would find acceptable to determine radionuclide concentrations and demonstrate compliance with the waste classification requirements is through a program of materials accountability.
That is, a given quantity (and resulting concentration) of radioactive material may be known to be contained within a given waste or may be inferred through determining the difference between the quantity of radioactive material entering and exiting a given process.
This procedure is expected to be most useful for licensees who receive and possess only a limited number of different radioisotopes in known
5 concentrations and activities (e.g., holders of source material, special nuclear material, or specific byproduct material licenses).
An example would be a biomedical research facility at which known amounts of a radioisotopes are injected into research animals, the carcasses of which are ultimately disposed as radioactive waste.
Another example would be a research or test facility performing activation analysis experiments.
In this case, the quantity of radioactive material within a given waste stream may be inferred through calculation.
This method may also be used to determine the absence of particular radionuclides.
That is, for most licensees, the absence of particular radionuclide may be determined through a knowledge of the types of radioisotopes received and possessed, as well as the process producing the waste.
For example, if a licensee receives, possesses and uses only tritium, there is no need to measure the waste stream for other isotopes such as iodine-129 or cesium-137.
b.
Classification by Source This method is similar to the above method of materials accountability and involves determining the radionuclide content and classification of waste through knowledge and control of the source of the waste.
This method is expected to be useful for occasions when the radionuclide concentrations within waste generated by a particular process are relatively constant and unaffected by ninor variations in the process.
This method is also expected to be frequently useful for determining the absense of particular radionuclides from a given waste For example, within a given licensed facility there may be a stream.
number of separate controlled areas within which only a limited number of radioisotopes are possessed and used (e.g., Cs-137 may be used in one area and tritium in another).
As long as facility operations are conducted so that transfer of radioactive material from one controlled area to another cannot occur, waste generated from a particular area
6 may be readily classified by source.
An example of a licensee for which this method is expected to be useful is a large university which holds a broad license for byproduct material, c.
Gross Radioactivity Measurements Measurements of gross radioactivity are, in general, acceptable for Class A waste streams (and for which minor process variations are not likely to result in the waste being in a higher waste class) but generally unacceptable for Class B and Class C waste streams.
Measurements of gross radioactivity would also be generally unacceptable for waste streams containing radionuclides in concentrations which may exceed (e.g., within a factor of 10) maximum allowable concentrations for near-surface disposal.
However, there may be some (a limited number) Class B or Class C waste streams having odd geometries or physical characteristics which make collection of samples and/or data difficult.
In such cases, gross measurements may be the only practicable means of determining radionuclide concentrations.
In addition, there may be some Class B and Class C waste streams for which the distribution of radionuclides within the waste streams is essentially fixed (e.g., a waste stream whose radionuclide distribution is known and either the distribution is insensitive to process changes or the process generating the waste streams is relatively nonvariable) and minor process changes are not likely to result in a significant change in this distribution.
Gross radioactivity measurements are also acceptable in this case provided that radionuclide distributions are initially determined and periodically verified by direct measurement techniques.
Licensees carrying out gross radioactivity measurements to assure compliance with the waste classification requirement must establish a program to correlate and calibrate measured radioactivity levels with radionuclide concentrations in wastes prepared for shipment.
This program must take into account waste pack ge and detector geometry, shielding and attenuation effects, the effective gamma energies of the s
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.l emitted photons, and the number of photons per decay.
The accuracy of the correlation should be periodically checked through more detailed sample analysis involving measurement of _ specific radionuclides.
The accuracy of the correlation should also be checked whenever there is reason to believe that process changes may have significantly altered previously de*. ermined correlations.
In general, the frequency of confirmatory analysis should increase with increasing radionuclide concentrations.
For Class A waste, for example, more frequent confirmatory analysis should be performed for wastes approaching the Class B limit.
In addition, more frequent confirmatory analysis should be performed for radioisotopes readily measured individually.
For example, one or two Class A waste packages out of a batch could be analyzed for gamma-emitting radionuclides such as Co-60 or Cs-137.
Analysis for pure beta emitters such as Sr-90 would be performed less frequently.
d.
Measurement of Specific Radionuclides Another method acceptable to the regulatory staff for determining radionuclide concentrations in waste is direct measurements for individual radionuclides.
Measurements to identify and quantify specific radionuclides within final waste forms should be performed:
- Routinely for wastes for which minor process variations could cause an upward change in waste classification;
- Routinely for Class B and Class C wastes, or wastes which contain radionuclides in concentrations which have a reasonable possibility of exceeding maximum allowable concentrations for near surface disposal;
- Periodicly to confirm the correlation of measurements made from gross-radioactivity measurements; and
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- Whenever there is reason to believe that facility or process changes may have significantly altered previously determined correlations of gross radioactivity measurements.
l Radionuclide concentrations should be determined based upon the volume or weight of the final waste form.
A preferred approach is to take samples for analysis either from the final waste form or from the waste af ter any volume reduction but prior to solidification.
- However, NRC will accept samples taken from an intermediate process step provided that the results of the sample analysis can be directly translated to the final waste form. The minimum sensitivity of a measurement technique for direct measurement of a particular radionuclide should be no more than 0.01 times the smallest concentration for that radionuclide listed in Table 1.
A discussion of acceptable sampling programs is provided as Appendix B to this BTP.
It is recognized that some radionuclides are amenable to routine quantification by direct measurement techniques (e.g., gamma-spectral analysis of isotopes such as Co-60 or Cs-137), while other radionuclides require more costly and time consuming analysis frequently removed from the waste generator's facility.
For these latter radionuclides, the regulatory staff will generally accept determinations of concentrations through use of scaling factors whereby concentrations of radioisotopes which cannot be readily measured (through techniques such as gamma-spectral analysis) are projected through ratioing to concentrations of radioisotopes which can be readily measured.
An example would be the practice of scaling transuranic concentrations to concentrations of the isotope Ce-144.
Scaling factors should developed on a facility and waste stream specific basis, and should be furthermore initially determined through direct measurement techniques.
The representativeness of the scaling factors should be periodically confirmed through direct measurements on at least a semi-annual basis.
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2.
Reporting on Manifests Section 20.311 requires that the total quantity of the radionuclides listed in Table 1 of Section 61.55 be recorded in shipment manifests.
For isotopes having half lives less than 5 years,
'only those isotopos which contribute significantly to the total activity need be recordad.
In the manifests, if a particular radioisotopes is known to be not present within a waste stream (e.g., through material accountability), the quantity of the radionuclide should be recorded as "not present".
If the radionuclide is determined to be present in the waste and the radionuclide quantity is determined through material accountability, direct measurement, or inference through direct measurement or gross radioactivity measurement, this quantity should be reported as determined.
If the radionuclide is known or suspected to be contained within the waste but is in concentrations less than the minimum sensitivity limit for the measurement technique, the quantity of the radionuclide should be recorded as "zero", with the sensitivity of the measurement technique included alongside in parentheses.
Shipment manifests should also record the date for which the classification determination is valid.
This can be, for example, the date of transfer of the waste package from the site of generation.
In no case should the date chosen for decay correction be beyond the date on which the waste is removed from the site of generation.
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10 Appendix A.
General Program for Classifying Wastes at Nuc1 car Power Facilities r
In order to meet the requirements in 10 CFR 61 to classify radioactive wastes at nuclear power plants, NRC staff has prepared a general program for implementing the waste classification syste'm.
This implementation program consists of a three tiered approach which includes:
(1) Periodic analysis for all nuclides listed in Table 1 of Section 61.55, (2) Gamma spectroscopy of certain nuclides from which waste classification nuclides are correlated, and (3) Dose-rate measurements which correlate activity levels of wastes from similar batches to the gamma-spectroscopy measurements.
The periodic sampling for listed nuclides would be performed on a semiannual basis.
This sampling would be performed on various waste streams in the plant.
Therefore, samples should be taken from individual waste streams such as boric acid evaporator bottoms, primary system cleanup resins, chemical regenerative evaporator bottoms, etc.
If unit operations are modified for any of the individual waste streams such that the nuclide distribution would be expected to change, a reanalysis should be performed.
Likewise, if any plant operations could cause a significant change to the nuclide distribution in the wastes, such as a change in the failed fuel fraction or a crud burst, a reanalysis should be performed.
If operations remain consistent, consideration will be given to performing reanalysis on an annual rather than semiannual basis.
These periodic analyses should be '.he basis for establishing correlation factcrs between the waste classification nuclides and nuclides which can be more easily measured using gamma-j spectroscopy techniques.
,e
P 11 The gamma spectroscopy measurements should be performed on individual waste batches.
This can be performed by analyzing waste samples, prior to or after solification, analyzing waste drums or liners by any of the commercial devices designed for this task, or by analyzing influent and effluent samples from the process stream. Other methods which provide reasonable' analysis will also be considered.
Efforts should be made to obtain reasonably representative samples for an'alysis.
The results of the gamma spectroscopy measurements should be applied with the correlation factors to obtain concentrations for those nuclides listed in the waste classification table.
Dose rate measurements may also be performed on individual drums from similar waste batches for which gamma-spectroscopy results are available.
Dose rate measurements should include corrections for attenuation and container size and configuration.
The dose rate measurements should be used to scale the nuclide concentrations obtained from the gamma spectroscopy data and correlations.
The NRC staff believes that the above approach presents a workable and enforceable program for implementing the waste classification system.
This approach should minimze the administrative and operational burdens on plant personnel, but still provide reasonably accurate data for use in quantifying disposal site nuclide concentrations and inventories.
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12 Appendix B:
Sampling Programs For Measurements of Specific Padionuclides In the body of this technical position paper, the staff recommends criteria for when a licensee's program for determining the classification status of a radioactive waste stream should include measurements for specific radionuclides.
This appendix provides additional recommendations regarding sampling programs used to determine radionuclide concentrations.
1.
Representative Samples A sample should be representative of the bulk stream or volume o'f waste form which it is taken.
Provisions should be made to assure that representative samples are obtained from well-mixed streams or vclumes of waste by the selection of proper sampling equipment, the proper location of sampling points, and the development and use of proper sampling procedures.
Prior to sampling, large volumes of liquid waste should be mixed in as short a time interval as practicable to assure that any sediments or particulate solids are distributed uniformly in the waste mixtu,re.
Sample points should be located where there is 1 minimum of disturbance of flow due to fittings and other physical characteristics of the equipment and components.
Sample nozzles should be inserted into the flow or liquid volume to ensure sampling the bulk volume of pipes and tanks.
Sample lines should be flushed for a sufficient period of time prior to sample extraction in order to remove sediment deposits and air and gas pockets.
Periodically, a series of samples should be taken during the interval of discharge to determine whether any differences exist as function of time and to assure that individual samples are indeed representative of the waste mixture.
Multiple samples of waste streams such as ion exchange rasins and filter sludges should be collected and composited when sampling large volumes of these materials in holding tanks and similar storage containers.
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Composite Samples Two types of samples may be composited for analysis:
(a) those representing bulk materials in holding tanks which are fed to batch solidification and/or packaging processes and (b) those representing materials fed during a specified time interval to continuous solidification and/or packaging processes.
Periods of collection for both types of samples for compositing should be as short as practicable to avoid loss of radioactive material by deposition on walls of the sample container or by volaillization of potentially volatile materials.
Both types of composite samples should be thoroughly mixed prior to analysis.
For batch processes, each holding tank or similar container should be characterized by a single composite.
For continuous processes, samples should be collected for compositing in proportion to the rate of flow.
3.
Time Between Collection and Analysis Reduction in radionuclide concentrations due to radioactive decay between collection and analysis is believed to be generally not of concern for purposes of waste classification.
However, procedures should be instituted for handling, packaging, and storing the samples to assure that loss of radioactive material due to deposition, volatilization, or other factors does not invalidate the analysis.
4.
Decay Corrections To estimate radioactive decay of composited samples, weighting should be applied to the decay time of each portion and to the quantity of each portion in relation to the total quantity of the sample.
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