ML20138L951

an Evaluation of Radionuclide Concentrations in HIGH-LEVEL Radioactive Wastes

ML20138L951
Person / Time
Issue date:	10/31/1985
From:	Fehringer D NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS)
To:
References
NUREG-0946, NUREG-946, NUDOCS 8510310448
Download: ML20138L951 (34)

Text

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NOREG-0946 An Evaluation of Radionuclide Concentrations in High-Level Radioactive Wastes i

U.S. Nuclear Regulatory Commission Office of Nuclear Material Safety and Safeguards D. J. Fehringer l p>* "%q,

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A NOTICE Availability of Reference Materials Cited in NRC Publications j Most documents cited in NRC publications will be available from one of the following sources:

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1. The NRC Public Document Rocm,171'i H Street, N.W.

Washington, DC 20565

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NUREG-0946 An Evaluation of Radionuclide Concentrations in High-Level Radioactive Wastes m,--- ,--.. --.-.<- -- --- - - - - - - - - - - - - - - _ , -

Manuscript Completed: March 1985 Date Published: October 1985 D. J. Fehringer Division of Waste Management Office of Nuclear Material Safety and Safeguards U.S. Nuclear Regulatory Commission Wcshington, D.C. 20555 1

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t ABSTRACT 1

! This report describes a possible approach for development of a numerical l definition of the term "high-level radioactive waste." Five wastes are identified which are recognized as being high-level wastes under current,

! non-numerical definitions. The constituents of these wastes are examined and l the most hazardous component radionuclides are identified. This report

,; suggests that other wastes with similar concentrations of these radionuclides

could also be defined as high-level wastes.

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TABLE OF CONTENTS Page INTRODUCTION . . . . ...... ....... ... . 1 CURRENT HLW DEFINITIONS .... .... ...... .. 2

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OTHER WASTE CLASSIFICATIONS ............... . 4 CHARACTERIZING THE HAZARD OF HLW . . ...... ..... . 5 REPRESENTATIVE HLW WASTE STREAMS AND FORMS . . . . . . . . . 17 Savannah River Plant (SRP) " fresh" . . . . . . . . . . . . 17 Savannah River Plant " reconstituted" . . . ......... 19 West Valley " Tank 802" . . . . . . ............. 19 Commercial Liquid HLW ................. . 19 Spent Fuel . . . . . . . ........ ........ 20 CHARACTERISTICS OF WASTES .............. ... 20 CONCLUSIONS . ...................... 27 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . 28 I

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LIST OF FIGURES Figure g 1 PWR Spent Fuel -- Radioactivity . ............. 6 2 Uranium Recycle Reprocessir.g Waste -- Radioactivity . . . .. 7 3 Mixed 0xide Reprocessing Waste -- Radioactivity . . . . . . . . 8 4 PWR Spent Fuel -- Untreated Oilution Index .......... 10 5 Uranium Recycle Reprocessing Waste -- Untreated Dilution Index 11 6 Mixed 0xide Reprocessing Waste -- Untreated Dilution Index .. 12 1

7 PWR Throwaway Cycle -- Untreated Dilution Index Based on ICRP-30 Dosimetry ................. 14 8 Reprocessed Waste -- Untreated Dilution Index Based on ICRP-30 Dosimetry ................. 15 9 Mixed 0xide Reprocessing Waste -- Untreated Dilution Index Based on ICRP-30 00simetry .............. .. 16 I

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LIST OF TABLES Table Page 1 Concentrations and Ratios to MPC for Five Wastes . . . . . . . 21 2 Concentrations and Ratios to Annual Limit of Intake (ALI) for Five Wastes ..................... 23 3 Concentrations and Ratios to ALI Af ter 100 Years Decay for Five Wastes ................ ..... 24 4 Concentrations and Ratios to Class C Limits for Five Wastes . 26 1

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i AN EVALUATION OF RADIONUCLIDE CONCENTRATIONS IN HIGH-LEVEL RADI0 ACTIVE WASTES

Introduction:

It has long been recognized that certain radioactive materials produced in the uranium fuel cycle are sufficiently hazardous to require disposal in a manner that results in permanent isolation from the environment, and these materials have been termed "high-level radioactive wastes" (HLW). The term "high-level radioactive waste" is currently defined qualitatively and refers to the source (namely, spent fuel and waste from

reprocessing operations), rather than the hazard of a waste stream. The Nuclear Waste Policy Act (NWPA) recognizes that wastes from other sources may present equivalent hazards and may require treatment and disposal in a similar manner. Thus, under section 2(12)(B) of NWPA, "high-level radioactive waste" means not only wastes from reprocessing but also "other highly radioactive material that the Commission, consistent with existing law, determines by rule requires permanent isolation."

The purpose of this evaluation is to determine whether it is feasible to develop a concentration-based approach which could be used to identify other highly radioactive material requiring permanent isolation. Concentrations are derived from consideration of representative waste streams and forms traditionally considered to be HLW. A table, based on these concentrations, is developed identifying the important radionuclides and associated concentrations. Highly radioactive material containing these radionuclides in similar or higher concentrations could then be classified as HLW. Such an approach is attractive as it would preserve consistency with the Commission's present definitions of HLW, such as set forth in 10 CFR Part 60.

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i This evaluation seeks to determine the approximate range of radionuclide concentrations which would identify radioactive wastes requiring permanent isolation. Should the Commission decide that a generic numerical definition l (in terms of radionuclide concentrations) is an appropriate way to identify i such wastes, the values derived in this paper could be used in such a

definition. They represent the NRC staff's best current estimate of the radionuclide concentrations which would require permanent isolation. However, additional studies may be needed before formally proceeding with a numerical definition as a proposed rule in order to make certain that the values are low enough to capture most of the wastes that do require permanent isolation without including wastes that do not require such isolation.

Current HLW Definitions: The Atomic Energy Commission staff, in its staff paper regarding the proposed policy " Siting of Commercial Fuel Reprocessing Plants and Related Waste Management Facilities," (ref. 1) defined high-level liquid wastes as:

"-those which, by virtue of their radionuclide concentration, half-life and biological significance, require perpetual isolation from the biosphere, even after solidification. The only anticipated sources of such wastes in significant quantities are those aqueous wastes resulting from the operation of the first cycle solvent extraction system and the concentrated wastes from subsequent extraction cycles in a facility for reprocessing irradiated reactor fuels."

In the proposed Appendix 0 to 10 CFR Part 50 that was eventually published in the Federal Register for comment (34 FR 8712), an abbreviated definition was employed:

"For the purposes of this statement of policy, high-level liquid radioactive wastes means those wastes resulting from the operation of the first cycle solvent extraction system and the concentrated wastes from subsequent extraction cycles in a facility for reprocessing irradiated reactor fuels."

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This abbreviated definition, with minor changes to apply to equivalent waste streams from alternative reprocessing systems, was incorporated into the final rule, Appendix F to 10 CFR Part 50 (35 FR 17530), and the term "high-level radioactive waste" was subsequently used in 10 CFR Part 60, pertaining to disposal at a geologic repository, to also include spent nuclear fuel and solidified high-level liquid wastes.

The staff paper did not indicate the range of concentrations, half-lives or biological significance the AEC staff considered would require perpetual isolation. However, the Federal Register notice for the final rule ref erenced AEC contractor studies that provided the basis for the costs of implementing the final rule (ref. 2). This report contains calculated inventories of radioactive materials in wastes from reprocessed commercial light water reactor and liquid-metal cooled fast breeder reactor fuels for times up to 1,000 years after reprocessing. In the report, high-level wastes are defined o

as wastes that contain radionuclides in excess of 10 times the maximum permissible concentrations for ingestion (MPC,) recommended by the International Commission on Radiological Protection (ref. 3). The contractor study notes that about five cubic miles of water would be required to dilute to MPC , the fission products present in the waste obtained from processing one metric ton of fuel that had been irradiated to an exposure of 10,000 Mwd (thermal). The contractor study further notes that the wastes would contain variable quantities of actinides, notably isotopes of Pu, Am and Cm, with half-lives and biological toxicities that impose additional restrictions. The contractor study stated that fission product separation, dilution or decay would not offer a feasible method of managing these wastes.

Thus, it is clear that both concentrations and duration of hazard have been important considerations in previous attempts to define HLW.

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i Other Waste Classifications: In 10 CFR Part 61, " Licensing Requirements for l Land Disposal of Radioactive Waste" (47 FR 57446), the NRC defined three classes of radioactive wastes (Classes A, B and C) which are routinely acceptable for disposal in shallow land burial facilities. Class C wastes represent the highest radionuclide concentrations of the three classes, and the maximum Class C concentrations are defined as follows:

Long-lived nuclides: Short-lived nuclides:

3 C-14 8 Ci/m Total all nuclides, C-14 in activated a half-life < 5 yrs no limit metal 80 Ci/m H-3 no limit Ni-59 in activated 3 Co-60 no limita metal 220 Ci/m Ni-63 700 Ci/m Nb-94 in activated 3 Ni-63 in activated a metal 0.2 Ci/m a metal 7000 Ci/m a ,

Tc-99 3.0 Ci/m 3 Sr-90 7000 Ci/m3 I-129 0.08 Ci/m Cs-137 4600 Ci/m Alpha emitting TRU, half-life > Syrs 100 nCi/gm Pu-241 3500 nCi/gm Cm-242 20,000 nCi/gm When a mixture of radionuclides is present in a waste, a sum-of-the-fractions rule is applied to determine how the mixture should be classified.

The Class C definition of Part 61 identifies waste concentrations routinely acceptable for shallow land burial, but also allows case-by-case evaluations of wastes with concentrations exceeding the Class C limits. These limits are therefore not appropriate for identifying wastes requiring permanent isolation, although they do limit the range of concentrations which might be considered for classification as high-level wastes.

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J Characterizing the Hazard of HLW: The discussion which follows is largely drawn from reference 4.

As nuclear fuel is irradiated in a nuclear reactor, three types of radioactive products are formed. Fission products are generated by fissioning uranium and plutonium isotopes and, with a few exceptions, are characterized by relatively short half-lives and low radiotoxicity. Actinides are radionuclides with atomic numbers greater than 88, and result from non-fission neutron I absorptions in uranium. The actinides typically have longer half-lives and higher radiotoxicities than the fission products. Small quantities of additional radionuclides, called activation products, are produced by neutron absorption in the structural materials which support and contain the fuel in a reactor. The activation products make only a minor contribution to the overall radiotoxicity of HLW, and will not be discussed further.

Figure 1 presents the radioactivity of pressurized water reactor (PWR) spent fuel as a function of time after removal from a reactor, while Figures 2 and 3 present the same information for the wastes which would result from reprocessing the spent fuel from the uranium recycle and mixed oxide fuel 1

cycles, respectively.* (Figures 1-3 are normalized on the basis of one metric tonne of heavy metal (MTHM) initially charged to a reactor.)

i *In the uranium recycle fuel cycle, it has been assumed that 99.5% of i the plutonium in spent fuel is recovered and placed in storage, while the recovered uranium is returned to the fuel cycle. In the mixed oxide fuel cycle, both plutonium and uranium are returned to the fuel cycle.

l Ref. 5 discusses additional assumptions.

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3pl ,u e-e., ' l I 'lllli i l lIlllll l l lllllll tc3 tal to2 19 te 4 ios ,qs c , r,,,. ,,. o n.,,. i v ,,,

Figure 5. Uranium Recycle Reprocessing Waste --

Untreated Dilution Index (Ref. 5) t 11 I

I 1o'2

( . .

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procucts of all mlbee comeocents of trte fuel I '

l ' ' ' ' ' '

• """v-

,g i lIlllil I I llll!il lll1llll 19 to' id is ic4 id iod c.C., r:.. ,,.m c.icwn iy u Figure 6. Mixed Oxide Reprocessing Waste --

Untreated Dilution Index (Ref. 5) 12

1 i

j i

i Recent revisions in the ICRP's recommendations for dosimetry calculations

! (ref. 6) would cause some significant changes in this measurement of the j relative hazard of HLW :.s a function of time. This effect has been noted recently in the scientific literature by a number of authors (ref. 7, 8 and 9). Revised curves, based on the more recent ICRP recommendations (ref. 6),

]

j are displayed in Figures 7, 8 and 9 for spent fuel and reprocessing wastes, j (The NRC has not formally adopted ICRP-30, but the procedures described in j it have been used here because it is the most current ICRP publication on j internal dosimetry available.) The most significant results of the ICRP I revisions are:

}

j

1) the hazard of some of the fission products (primarily Sr-90) is

]

reduced, l

2) the hazard of several of the long-lived actinides is increased

]

1 (especially Am-241, Am-243 and Np-237), and 3

3) the hazard of Ra-226 is reduced and, as a result, the hazard of the l original uranium ore is reduced.

i l The UDI curves of Figures 4-9 indicate that the toxicity decreases substantially (90% - 99.9%) during tne first 1000 years for all three waste j types and for both dosimetry approaches considered. The toxicity of the j fission products decreases by more than five orders of magnitude during the

! first 1,000 years and then remains essentially constant for the next 100,000 l j years. Figures 4-9 also indicate that radioactive decay of spent fuel and l i

j reprocessing wastes during the first 10,000 years reduces the toxicity of j these materials to approximately that of the original uranium ore from which

] they were derived, although this comparison is strongly dependent on the

! dosimetry approach employed, t 4 r I

13

10

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t0 0 Decay T1=e fr=s Discharge (yrs.)

Figure 7. PWR Throwaway Cycle -- Untreated Dilution Index Based on ICRP-30 Dosimetry 14

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Figure 8. Reprocessed Waste -- Untreated Ollution Index Based on ICRP-30 Dosimetry 15

r. J

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Decay Time fr:.. Discharge (; ;s.)

Figure 9. Mixed 0xide Reprocessing Waste -- Untreated Dilution Index Based on ICRP-30 00simetry 16

i l

l The " untreated dilution index" can provide some perspective regarding the intrinsic toxicity of a radioactive material, but is subject to the following limitations:

o The UDI does not consider the physical or chemical form of the radioactive material. Properties such as solubility or leachability may significantly affect the true hazard to human health, o The location of the material and the pathways through which it could reach humans are not considered.

o There is considerable uncertainty inherent in the dosimetry parameters upon which the UDI is based, leading to considerable uncertainty in the index itself.

In the past, the UDI (also referred to as " Ingestion Hazard Index" or simply

" Hazard Index") has been widely used to identify the most radiotoxic components of wastes (e.g., ref. 4, 5, 13 and 14). In spite of its limitations, this index can provide an approximate estimate of the relative toxicities of individual nuclides as they exist in a waste. Figures 4 - 9 also give an approximate estimate (as a function of time) of the relative toxicities of wastes and the original uranium ore from which the wastes were derived.

Representative HLW Waste Streams and Forms: Using the Commission's current definitions of HLW, five HLW waste streams and forms were identified as being representative of wastes requiring permanent isolation:

(1) Savannah River Plant (SRP) " fresh" (ref. 10). This waste stream is taken to be representative of the defense high-level liquid wastes being produced when the NRC's current HLW definitions were developed.

17

1 l

This waste is a composite liquid waste stream containing both "first cycle" and subsequent cycle wastes resulting from reprocessing defense wastes six months after removal from a reactor. The reprocessing technology employed at SRP is representative of recent (and probably of future) defense waste processing, although it is not representative of some of the earliest separations technology employed at the Hanford site *.

• Two defense HLW inventories at Hanford and Idaho were deemed not to be representative for purposes of deriving the concentration limits.

(1) While the defense wastes at the Hanford site represent a sizeable inventory, they were not included in this work for two reasons.

First, little relevant information is available. Published information gives estimates of the total waste inventories at Hanford, but does not provide detailed information on radionuclide concentrations. Second, the wastes at Hanford are not particularly representative of the types of wastes which the Commission has defined as HLW. Some of the wastes were separated using chemical j process technologies now considered obsolete, and some of the wastes have been processed as many as three times for separation of plutonium, uranium and high-heat generating nuclides (Sr-90 and Cs-137). In addition, the variety of reactors and operating conditions employed at Hanford argue against considering the Hanford wastes as " typical" HLW. For these reasons, the SRP wastes were selected as being more representative of defense HLW.

(2) The defense wastes at Idaho were also excluded from this study for the purpose of determining representative concentrations of waste constituents. These wastes were derived from naval reactor fuels with compositions and burn-ups substantially different from other defense and commercial reactor fuels, and therefore are not considered to be representative of the bulk of the high-level wastes likely to be disposed of in the future.

18

(2) Savannah River Plant " reconstituted" (ref. 10). This waste is representative of the inventory of defense wastes currently in storage and is considered to be the most representative of defense HLW concentrations likely to be disposed of during the next few decades. These wastes include both "first-cycle" wastes and

" concentrated intermediate" wastes, and represent the waste stream which would result if the wastes currently stored in SRP tanks (both sludge and supernatant) were reconstituted to a slurry for removal from the tanks. Because most of the wastes have been stored for several years, most of the short-lived nuclides have decayed away.

(3) West Valley " Tank 802" (ref. 11). The West Valley wastes represent an actual waste inventory requiring disposal. This waste is analogous to the SRP " reconstituted" waste in that it is a hypothetical waste stream which would result if the sludge and supernatant of Tank 802 were reconstituted to a slurry for removal from the tank. Both commercial and defense wastes are present in Tank 802. Although some commercial wastes were reprocessed at West Valley, burn-ups were generally low and the radionuclide concentrations are only moderately higher than for defense wastes.

(4) Commercial Liquid HLW (ref. 12). This is a hypothetical waste stream based on reprocessing light-water reactor fuels with burn-ups typical of current commercial operating practices, and represents a potential waste stream requiring disposal in the future in the event that reprocessing of commercial reactor fuels is undertaken.

19

(5) Spent Fuel (ref. 12). In the absence of commercial reactor fuel reprocessing, disposal of spent fuel is expected to be the major source (in terms of radioactivity) of commercial high-level wastes in the future. This waste stream gives a rough estimate of the ralionuclide concentrations in the fuel pins of spent light-water reactor fuel. The diluting effect of cladding, hardware, and void spaces between fuel pins was not included. Thus, this waste I stream overestimates the actual nuclide concentration in a waste package containing spent fuel.

Characteristics of Wastes: Table 1 displays the concentrations of many of the radionuclides in the five waste streams described above. Also presented in Table 1 are the ratios of these concentrations to the maximum permissible concentrations (MPC) for ingestion (taken from 10 CFR Part 20 which is based, with a few modifications, on the recommendations of ref. 3) to allow a comparison with the high-level waste definition used in ref. 2.*

Each of the five waste streams exceeds the high-level waste definition of 6

ref. 2 (10 times MPC) by at least three orders of magnitude, suggesting that these wastes were clearly considered to be high-level wastes when the Commission's current definition of the term was developed. The most prominent nuclides, in terms of their ratios to MPC, are Sr-90 and Cs-137, with the actinides being present at ratios closer to the ref. 2 definition.

• This is not to suggest that the HLW definition of Ref. 2 should be adopted by the NRC. Rather, a comparison with the Ref. 2 definition is presented to gain some perspective regarding the types of radioactive materials which were considered to be "high-level" at the time Ref. 2 (and the NRC's current HLW definition) were published.

20

West valley 10 v Old Co*a 10 v Old SPD (feesa) Sep (r, constitutes) 1 sat 802 (total) t-qu e ate 5 peat Fuel liatto satio Estio satio satio muetto, Ci/e1 te **C C4/m3 to **C Ci/*$ to upC Ci/*8 te "8C Ci/e1 to ##C f Ce-144. Pe-144 1.8E*4 1.8E*9 5.0E*1 5.CE*6 1.1E-2 1.1E*3 2 7E*2 2. 7E

• 7 1. 6 E

• 3 1.6E*8 P=-147 3.CE*3 1.5E*7 2.0E*2 1.0E*6 3.0E*1 1.5E*5 1.1E*4 5.5E 7 6 4E+4 3.2E*8 ar 106. Rh-106 1.0E*3 1.0E*8 7.9E*0 7. 9E

• 5 1.1E 1 1.1E*4 1.1E*3 1.1E*8 6.8E+3 6.8E*8 Sr40 8 OE*2 2.7E*9 5.5E*2 1.8E*9 3.3E*3 1.1E*10 8.7E*4 2.9E*11 5.2E*5 1.7E*12 Cs 137 8.0E+2 4.0E*7 5.8E*2 2.9E*7 4.4E*3 2.2E*8 1.2E*5 6.0E*9 7.5E+5 3.8E*10 Cs-134 3 CE*2 3.3E*7 - ho Data - 1. C E +1 1.1E+6 9.5E*3 1.1E*9 5.7t+4 6.3E+9 So-151 2.0E*1 5.0E*4 1.8E+1 4 5E*4 1.0E*2 2.5E+5 1.8E*3 4 SE*6 1.1E*4 2.8E+7 Tc-99 1.0E 1 5.0E*2 ho Data - 9.5E-1 4.8E+3 2.2E*1 1.1E4 1.3E+2 6.5E+5 Er154 3.0E-2 1.5E*3 - no Data - 6.5E*1 3.2E4 6.2E*3 3.1E+4 3.7E+4 1.8E*9 2r-93 3.0E-2 3.8E*1 - ho Data - 1.2E-1 1.5E*2 2.8E*0 3.5E*3 1.7t+1 2.1E+4 Cs-135 1.0E-2 1.0E*2 - no Cata - 1.8E-2 1.8E+2 4.5E-1 4.5E*3 2.7t+0 2.7E+4 Sn-126 3.0E-3 1.0E+3 - no Data - 6.0E-2 2.0E+4 1.6E+0 5.3E+5 9.6E+0 3.2E4 57-79 3.0E-3 1.0E*3 - no Data - 2.5E-2 8.3E+3 5.8E-1 1.9E+5 3.5E+0 1.2E4 1 119 3.0E-4 5.0E+3 - ho Data - 2.4E-3 4.0E*4 2.8E-4 4 7E*3 3.3E-1 5.5E+6 Pu-238 3.0E*0 6.0E+5 2.6E+0 5.2E*5 7.5E-1 1.5E*5 5.2E*1 1.CE+7 2.0E+4 4.0E+9 Pr241 5.0E-1 2.5E+3 - no Data - 3 5E*1 1. 8E 4 5.5E*2 28E4 6.9E*5 3.4E+9 Co-244 3.0E-1 4.3E+4 2.6E 1 3.7E*4 4.4E*0 6.3E*5 1 4E*3 2 CE*8 9.0E+3 1.3E+9 es-241 3.0E 1 7.5E+4 2.6E-1 6.5E+4 1.0E+1

• 5E*6

. 6.1E*2 1.5E*8 1.6E+4 4. M +9 Pr239 1.CE 1 2.0E+4 1.1E-1 2.2E*4 9.0E-1 1.8E*$ 2.4E+0 4 8E*5 2.9E+3 5. M+8 Pr 240 2.0E-2 4.0E+3 - no Cata - 4.8E-1 9.6E*4 5.5E+0 1.1E*6 4.5E+3 9.0E+8 hp-237 1.0E-4 3.3E+1 - no Data - 1.21-2 4.0E+3 7.8E 1 2.6E+5 3.1E+0 1.0E+6 es-243

• ho Data - - No Data - 1.1E 1 2.8E+4 2.2E+1 5.5E4 1.4E*2 3.5E+7 Totals 2.3E+4 4.7t+9 1.4E*3 1.8E+9 7.9E+3 1.1E+10 2.4E*5 3.0E+11 2.1E+6 1.8E+12 Table 1: Concentrations and Ratios to MPC for Five Wastes.

21

Because of the recent revisions in the ICRP's recommendations for dosimetry calculations (ref. 6), a new index was developed to provide an updated perspective on the relative hazards of the constituents of wastes. This index is defined as the ratio of the activity in a unit volume of waste to the Annual Limit of Intake defined in ref. 6, and represents the number of ALI's present in a unit volume of waste. Thus, HI; = Cg /ALI; where HI g is the modified hazard index, C; is the concentration, and ALI; is the Annual Limit of Intake (for non-occupational exposure) for nuclide i.

This index is, of course, a function of time and will change as a radionuclide concentration changes due to radioactive decay.

Table 2 displays the radionuclide concentrations and the corresponding ratios to the Annual Limit of Intake (ALI) for the same five wastes as in Table 1. Table 2 indicates the same general features as Table 1, with Sr-90 and Cs-137 dominating the hazard, although to a lesser extent than with the older dosimetry recommendations.

It has generally been recognized (e.g., ref. 15) that institutional controls are likely to be effective in controlling the hazards of wastes for at least a century after disposal, and it is therefore appropriate to consider the relative hazards of individual radionuclides at the end of a period of institutional control. Table 3 presents the radionuclide concentrations and ratios to ALI after 100 years of decay for each of the five wastes. At this time, the dominance of Sr-90 and Cs-137 has been reduced so that their hazard is within about an order of magnitude of the total hazard of the actinides, with the other fission products still representing a substantially lower hazard.

22

west valley 10 t Old Comm. 10 Y 01c 599 (fresn) SRP (reconstituted) Tank B02 (Total) Liquid Mtw Spent Fuel

"** '" 3 hvelide Ci/o 3 tn ALI Ci/m 3

to ALI Ci/m to ALI Ct/e 3 to ALI Ci/*3 to ALI Ce-144 P&l44 1.8E+4 9.0E+8 5.0E+1 2.5E*6 1.lE-2 5.5E+2 2.7E*2 1 4E+1 L 6E*3 8.0E+7 Pz-147 3.0E+3 7.5E+6 2.0E*2 5.0E+5 3.0E+1 7.5E+4 1.1E+4 2.8E+7 6 4E+4 1.6E+8 Ru-106, Rh-106 1.0E+3 5.0E+7 7.9E+0 4,4E*5 1.1E-1 5.5E*3 1.lE+3 5.5E+7 6.8E+3 3 4E+8 Sr- 90 8.CE+2 2.7E*8 5.5E+2 1.8E+8 3.3E+3 1.1E+9 8. 7E +4 2.9E*10 5 2E*5 1.7E*11 Cs-137 8.0E+2 8.0E+7 5.8E+2 5.8E+7 4.4E+3 4.4E+8 1.2E+5 1.2E+10 7.5E+5 7.5E+10

• Cs-134 3.0E+2 4.3E*7 - ho Data - 1. 0E + 1 1.4E+6 9 AE+3 1.4E+9 5.7E+4 8.1E+9 5m-151 2.0E+1 2.0E+4 1.8E*1 1.8E*4 1.0E+2 1.0E+5 1.8E+3 1.8E+6 1.1E+4 1.lE+7 Tc-99 1.0E-1 2.5E*2 - ho Data - 9.5E-1 2.4E*3 2.2E+1 5.5E+4 1.3E*2 3.2E+5 E u-154 3.0E-2 6.0E+2 - No Data - 6.5E+1 1.3E+6 6.2E+3 1.2E+8 3.7E+4 7.4E+8 Z r-93 3.0E-2 3.0E+2 - No Data - 1.2E-1 1.2E+3 2.8E+0 2.8E+4 1.7E+1 1.7E+5 Cs-135 1.CE-2 1.4E+2 - No Data - 1.8E-2 2.6E+2 4.5E-1 6.4E*3 2.7E+0 3.9E+4 Sn-126 3.0E-3 1.0E+2 - No DATA - 6.0E-2 2.0E+3 1.6E*0 5.3E*4 9.6E+0 3.2E+5 Se-79 3.0E-3 5.0E+1 - No Data - 2.5E-2 4.2E+2 5.8E-1 9.7E+3 3.5E+0 5.8E+4 I-129 3.0E-4 6.0E+2 - No Data - 2.4E-3 4.eE+3 2.8E-4 5.6E+2 3.3E-1 6.6E*5 Pu-238 3.CE+0 4.3E+6 2.6E+C 3.7E+6 7.5E-1 1.1E+6 5.2E+1 7.4E*7 2.CE+4 2.9E+10 Pu-241 5.0E-1 1.7E+4 - No Cata - 3.5E+1 1.2E+6 5.5E+2 1.8E+7 6.9E+5 2.3E+10 Co-244 3.0E-1 1.5E+6 2.6E-1 1.3E+6 4.4E+0 2.2E*7 1.4E+3 7.0E+9 9.0E+3 4.5E+10 As-241 3.0E-1 3.CE+6 2.6E-1 2.6E+6 1.0E*1 1 OE+E 6.1E+2 6.1E+9 1.6E+4 1.6E+11 Pu-239 1.0E-1 1.7E*5 1.1E-1 1.8E+5 9.0E-1 1.5E+6 2.4E*0 4.0E*6 2.9E*3 4.8E+9 Pu-240 2.0E-2 3.3E+4 - No Data - 4.8E-1 t,.0E+5 5.5E+0 9.2E+6 4.5E+3 7.5E+9 he-237 1.CE-4 1.4E+4 - No Cata - 1.2E-2 1.7E+6 7.8E-1 1.1E*S 3.1E+0 4.4E+8 An-243 - No Data - - No Data - 1.1E-1 1.lE+6 2.2E+1 2.2E+8 1.4E+2 1. 4E +9 Totals 2.3E+4 1.3E+9 1.4E+3 2.5E+9 7.9E+3 1.7E*9 2.4E+5 4.9E+10 2.1E+6 5.1E+11 Table 2: Concentrations and Ratios to Annual Limit of Intake (ALI) for Five Wastes.

23

teest Valley 10 v Old Comm. 10 Y Old SRp (fresh) SRP (reconstituted) Tank 802 (Total) Liquid Mtw Spent Fuel Eatio Eatio Eatio katto Eatto hucitee Ci/e 3 to ALI Ci/m 3 to ALI Cfim 3 to 4t! Ci/m 3

to ALI (t/m to All Co-144, Pr-144 -- -- " -- " " " ~ *- --

1 Po-147 " ~ ~ -- -- -- -- -- -- --

l l

Ru-106. RM-106 -- -- " -- -- -- " " --

Sr-90 7.3E+1 2.4E+7 5.0E+1 1.6E+7 3.0E+2 1.0E+8 7.9E+3 2.6E*9 4.7E+4 1.5E+10 Cs-137 8.1E+1 8.1E+6 5.8E+1 5.8E+6 4.4E+2 4.4E*7 1.2E+4 1.2E+9 7 6E+4 7.6E+9 Cs-134 -- -- -- -- -- -- -- -- -- --

Se-151 9.5E+0 9.5E+3 8.5E+0 8.5E+3 4.8E+1 4.8E+4 8.5E+2 8.5E+5 5.2E*3 5.2E+6 Tc-99 1.0E-1 2.5E+2 - No Data - 9.5E-1 2.4E*3 2.2E+1 5.5E+4 1.3E+2 3.2E+5 Eu-154 4.2E-6 8.3E-2 - No Cata - 9.CE-3 1.8E+2 8.6E-1 1.7E+4 5.1E+0 1.0E*5 2r-93 3.0E-2 3.0E+2 - No Cata - 1.2E-1 1.2E+3 2.8E*0 2.8E*4 1.7E+1 1.7E+5 Cs-135 1.0E-2 1.4E+2 - No Cata - 1.8E-2 2.6E*2 4.5E-1 6.4E-3 2.7E+0 3.9E+4 in-126 3.0E-3 1.CE+t %c DATA - 6.0E-2 2.0E+3 1.6E+0 5.3E+4 9.6E+0 3.2E*5 Se-79 3.0E-3 5.0E*1 - No Data - 2.5E-2 4.2E+2 5.eE-1 9.7E+3 3.5E+0 5.8E+4 I-129 3.0E-4 6.0E+2 - No Data - 2.4E-3 4.8E+3 2.8E-4 5.6E+2 3.3E-1 6.6E+5 Pu-238 1.4E+0 2 OE+6 1.2E+0 1.7E+6 3.4E ' 5.CE+5 2.4E 1 3 4E+7 9.CE+3 1.3E+10 Pu-241 3.9E-3 1.3E+2 - No Cata - 2.8E-1 9.4E+3 4.3E+0 1. 4 E + 5 5.4E+3 1.8E+8 Co-244 6.5E-3 3.3E+4 5.6E-3 2.8E+4 9.6E-l 4.8E+5 3.0E*1 1.5E+8 2.0E+2 9.8E+8 Am-?41 2.6E-1 2.6E+6 2.2E-1 2.2E+6 8.5E+0 8.5E+7 5.2E*2 5.2E+9 1.4E*4 1.4E+11 Pu-239 2.2E-1 3.7E+5 2.4E-1 4.0E*5 2.0E+0 3.3E+6 5.3E+0 8.8E+6 6.4E+3 1.0E+13 Pu-240 2.CE-2 3.3E+4 - No Data - 4.8E-1 8.0E+5 5.5E+0 9.2E+6 4.5E+3 7.5E+9 hp-237 1.3E-4 1.8E+4 - No Cata - 1.5E-2 2.1E+6 9.8E-1 1.4E+8 3.9E+0 5.5E+8 An-243 -

ho Data - - No Cata - 1.1E-1 1.1E+6 2.2E+1 2.2E+8 1.4E+2 1.4E+9 Totals 1.7E+2 3.7E+7 1.2E+2 2.6E+7 8.0E+2 2.4E+8 2.1E+4 9.5E+9 1.7E+5 2.0E+11 Table 3 : Concentrations and Ratios to ALI After 100 Years Decay for Five Wastes. .

24

The information presented in Tables 1-3 suggests that the hazard of high-level wastes is primarily due to three constituents: Sr-90, Cs-137 and actinides. (Because of the dynamics of chain decay in the actinide group, it appears inappropriate to single out individual nuclides as major contributors to the overall hazard.)

In order to gauge the hazards of high-level wastes relative to wastes suitable for shallow land burial, Table 4 was constructed. This table displays the ratios of radionuclide concentrations to the current Class C limits for each of the five wastes. On this basis of comparison, the high-level wastes are more concentrated (and therefore more hazardous) than Class C wastes by a factor of 30 or more for each waste considered.

25

Sep (frese best valier 10 v Ole Co== 10 v Old sat (receastitutee) faan 802 (Total) tiovie wt= speat twel Eatic Eatio Natio satic Eatto Owelice Ci/*3 to Class C Ci/m3 to Class C Ci/m3 to Class C Ci/*3 to Class C Ci/*3 to Cla Ce 144, Pr-144 1.8E*4 --

5.0E 1 -

1.1E-2 - 2.7E*2 -- 1.6E*3 --

Pe-147 3. 0E

• 3 --

2.QE*2 --

3.0E.1 -

1.1E+4 --

6.4E+4 -

t r 106, Ra-106 1. 0E

• 3 --

7.9E+0 --

1.1E-1 --

1.1E*3 --

6.8E+3 -

5r-90 8 OE*2 ' 1.1E-1 5.5E+2 7.9E-2 3.3E*3 4.7E-1 8.7E+4 1.2E*1 5.2E+5 7.4E*1 Cs-137 8.0E*2 1.7E-1 5.8E*2 1.3E-1 4 4E+3 9 6E-1 1.2E*5 2.6E+1 7.5E*5 1.6E*2 Cs 134 3.0E*2 --

no Cata - 1.0E+1 - 9.5E*3 - 5.7E+4 --

5*-151 2.0E*1 -- 1.8E+1 - 1. 0E

• 2 - 1.8E+3 - 1.1E*4 --

Tc 99 1.0E-1 3.3E 2 - No Cata - 9.5E-1 3.2E-1 2.2E*1 7.3E*0 1.3E+2 4.3E+1 Er154 3.0E 2 -- - ho 04ta - 6.5E+1 -- 6 2E*3 -- 3.7E+4 -

D-93 3.0E-2 --

- No Data - 1.2E 1 -- 2.8E+0 -- 1.7E+1 --

Cs 135 1.0E 2 --

- No Cata - 1.8E 2 4.5E-1 2.7t+0 --

Sn-126 3.0E-3 --

No Data - 6.0E-2 --

1.6E+0 --

9.6t+0 --

50-79 3.0E-3 - No Data - 2.5E 2 5.8E-1

-- -- -- 3.5E+0 --

I-189 3.0E-4 3.8E-3 - No Cata - 2.4E-3 3.0E-2 2.8E-4 3.5E-3 3.3E-1 4.1E+0 Pr238 3.0E+0 3.0E+1 2.6E*0 2.6E+1 7.5E-1 7 5E 0 5.2E+1 5.2E+2 2.0E+4 2.0E+5 Pr341 5.0E-1 1. 4 E-1 No Data - 3.5E 1 1.0E*1 5.5E*2 1.6E+2 6 9E 5 2.0E+5 Co-844 3.0E-1 3.0E+0 2.6E-1 2.6E*0 4.4E*0 4 4E*1 1.4E+3 1.4E+4 9.0E+3 9.0E+4 An-241 3.0E-1 3.0E+0 2.6E 1 2.6E*0 1.0E+1 1.0E+2 6.1E+2 6.1E*3 1.6E+4 1.6E+5 Pr239 1.0E 1 1.0E*0 1.1E 1 1.1E+0 9.0E-1 9.0E+0 2 4t*0 2 4tal 2.9E*3 2.9E+4 Pr240 2.0E-2 2.0E-1 - No Cata - 4.8E 1 4. 8E+0 - 5.5E+0 5.5E*1 4.5E+3 4.5E+4 ho-237 1.0E-4 1.0E 3 - ho Data - 1.2E-2 1.2E-1 7.8E-1 7.8E*0 3.1E+0 3.1E+1 As-243 - no Data - - ho Data - 1.1E 1 1.1E+0 2.2E+1 2.2E+2 1.4E+2 1.4E*3 Vetals 2.3E+4 3 OE+1 1.4E+3 3.2E+1 7.9E+3 1.8E*2 2.4E+5 2.1E+4 2.1E+6 7.2E+5 Table 4: Concentrations and Ratios to Class C Limits for Five Wastes.

26

I i

4

Conclusions:

Tables 1-3 indicate that three constituents of high-level wastes contribute predominantly to the hazards of these wastes: Sr-90,

} Cs-137 and the actinides. The comparison with Class C limits in Table 4 I shows the concentrations of these components of high-level wastes to be approximately a factor of 30 or more higher than the Class C limits for each high-level waste considered. It might therefore be appropriate to consider wastes with concentrations more than 30 times the Class C limits (at the

! time they are being classified for disposal) as representing hazards approximately equivalent to wastes currently defined as "high-level," and to require that these wastee be disposed of in a manner which provides l permanent isolation from the environment. The specific radionuclide I

concentrations which would require permanent isolation are:

Radionuclide Concentrations l Requiring Permanent Isolation l

l Sr-90 210,000 Ci/m Cs-137 138,000 Ci/m Alpha emitting TRU, -

Half-life > 5 yrs 3,000 nCi/gm Pu-241 105,000 nCi/gm with a requirement to apply a sum-of-the-fractions rule as when applying the Class C limits.

l 27

References:

1) " Siting of Commercial Fuel Reprocessing Plants and Related Waste Management Facilities," AEC 180/52, May 1, 1969.

2) Oak Ridge National Laboratory, " Siting of Fuel Reprocessing Plants and Waste Management Facilities," ORNL-4451, 1970.

3) International Commission on Radiological Protection, " Recommendations of the International Commission on Radiological Protection, Report of Committee II on Permissible Dose for Internal Radiation (1959)," ICRP Publication 2 (New York: Pergamon Press), 1960.

4) " Rationale for the Performance Objectives in 10 CFR Part 60," Enclosure G of SECY-83-59, February 9, 1983.

5) A. O. Little, " Technical Support of Standards for High-level Radioactive Waste Management," EPA 520/4-79-007A, Arthur D. Little, Inc., for U. S.

Environmental Protection Agency, 1977.

6) International Commission on Radiological Protection, " Limits for Intake of Radionuclides by Workers," ICRP Publication 30 (New York: Pergamon Press), Referred to as ICRP 30, 1979.

7) Croff, A. G., " Potential Impact of ICRP-30 on the Calculated Risk from Waste Repositories," Transactions of the American Nuclear Society, Vol. 39, pp. 74-75, Nov., 1981.

8) Cohen, B. L. , " Effects of ICRP Publication 30 and the BEIR Report on Hazard Assessments of High-Level Wastes," Health Physics 42, 133 (1982).

28

9) Runkle, G. E. , " Comparison of ICRP-2 and ICRP-30 for Estimating the Dose and Adverse Health Effects from Potential Radionuclide Releases from a Geologic Waste Repository," Sandia National Laboratories, Proceedings of Waste Management 82, Vol. 3, p. 59, University of Arizona, 1982.

10) Cheung, H. , B. G. Knaizewycz, and D. J. Kvam, " Characteristics of Defense High-Level Waste," NUREG/CR-0685, 1979.

11) U. S. Department of Energy, " Final Environmental Impact Statement:

Long-Term Management of Liquid High-Level Radioactive Wastes Stored at the Western New York Nuclear Service Center, West Valley," DOE /EIS-0081, 1982.

12) U. S. Department of Energy, " Technology for Commercial Radioactive Waste Management," DOE /ET-0028, 1979.

13) Kocher, D. C., A. L. Sjoreen and C. S. Bard, " Uncertainties in Geologic Disposal of High-Level Wastes--Groundwater Transport of Radionuclides and Radiological Consequences," NUREG/CR-2506, 1983,

14) National Research Council, "A Study of the Isolation System for Geologic Disposal of Radioactive Wastes," Waste Isolation Systems Panel, Board on Radioactive Waste Management, National Academy Press, Washington, D. C., 1983.

15) U. S. Nuclear Regulatory Commission, " Draft Environmental Impact Statement on 10 CFR Part 61 ' Licensing Requirements for Land Disposal of Radioactive Waste'," NUREG-0782, 1981.

29

NRC FoRu 335 1. REPORT NUMBE R (Ass,gned Dy ODC) nten U.S. NUCLE AR REGUL ATORY COMMISSION l

l BIBLIOGRAPHIC DATA SHEET NUREG-0946 /

4 TtTLE AND SUBTITLE (Ace

• Volume No., of apprwr.are) 2 fleave Dianhi l An Evduation of Radionuclide Concentrations in /

High-L el Radioactive Wastes a RECIPIENT S ACCESSION NO

7. AUTHOR (S 5 D ATE REPORT CQVPLF 0 M ON TH Daniel J. F inger March / ThAs 8 9 PERFORMING OR N12ATION N AME AND M AILIP;G ADDRESS (Incloor 2 0 Codel DATE HE POHT[UED Division of Wa Management uoN m I eaa Office of Nucle Material Safety and Safeguards Octobe r f l1985 U.S. Nuclear Regu ory Comission 6 Washington, DC 20 't e> e[* '

8 (L blon e l 12 SPONSORING ORG ANIZ AllON VE AND M AILING ADDRESS (include I.0 Codel HO.lE C T T ASK WORK UNIT NO 11 FIN NO Same as 9, above.

13 TYPE OF RE PORT PE RIO' 'OV E RE O It'tclus-we aarest Final Technical Report

15. SUPPLEMEN T ARY NOTE S 14 lleece real

16. ABSTR ACT (200 words or ress/

This report describes a possible approach development of a numerical definition of the term "high-level radioactive waste. Five wastes are identified which are recognized as being high-level wastes und rrent, non-numerical definitions.

The constituents of these wastes are exa ned d the most hazardous component radionuclides are identified. This re rt sugg ts that other wastes with similar concentrations of these radionuclides auld also defined as high-level wastes.

17. KE Y WORDS AND DOCUVENT AN _YSIS I la DESC RIPTORS High-level waste Radioactive waste 17b. IDE NTIFIE RS OPE N-EN DE D TE RYS

18. AV AILABILITY ST ATE MENT 19 SE CURITY CL ASS ITh.s report / 21 NO OF P AGES Unclassified Unlimited 20 n*N S"s'di f@' ' ""'

""'ct s

NRC FORM 335 ist an l

EUM UMl J

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NUREG-0946 AN EVALUATION OF RADIONUCLlDE CONCENTHATIONS UU n UdtH 1985 l lN HIGH-LEVEL RADIOACTIVE WASTES l e9 jI  :

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