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The generation of secondary effluents starts beyond the TRUEX extraction step: Stripping of the Am-Cm-RE fraction from loaded CMPO-TBP: Washing of the TRUEX solvent: Separation of rare earths from Am-Cm (e.g. TALSPEAK): Am/Cm separation (method unknown): 500 l/tHM equiv. 250 l/tHM equiv. 3 000 l/tHM equiv. large volumes Compared to the classical PUREX process (5000 l/tHM) this additional TRUEX sequence will increase the bulk volume of effluents to be treated. Figure II.4 TRUEX process Feed solution (0.7-5 M HNO 3) CMPO TBP HNO 3 + H 2C 2O 4 rinse U, Pu, Np, Am, Cm, Ln(III) extraction FP, inert salts, H 2C 2O 4 HNO 3 Am, Cm, Ln stripping Am, Cm, Ln solution An/Ln Separation HNO 3 + HAN Pu, Np stripping Pu, Np solution Hydrazine oxalate Pu stripping Hydrazine carbonate U, Pu stripping U solution Solvent recycle One drawback of this process is the effect of solvent degradation products in the process. Some of these are cation exchangers which prevent the efficient stripping of the An(III)+Ln(III) fraction. Another problem is the difficulty in stripping U(VI) and An(IV) from the solvent due to their high affinity with CMPO. In order to eliminate this problem, the solvent clean-up step must be performed thoroughly with strong complexing agents e.g. hydrofluoric acid or diphosphonic acids (TUCS), but it causes the increase of the secondary waste. PNC proposed the use of “salt-free” reagents such as HAN, hydrazine oxalate and hydrazine carbonate which were adopted to the TRUEX flowsheet [7] (see Figure II.4). In addition, CMPO has been considered not to be effective for An(III)/Ln(III) separation. Currently, a new separation scheme has been proposed by PNC utilising DTPA as a selective strip reagent for An(III). It was demonstrated that An(III) could preferentially be co-stripped with Cm(III) and heavier Lns by DTPA-NaNO 3 solution and that partial fractionation was possible by this system named SETFICS [11]. 122
A computer code of the TRUEX process (GTM) was developed by G.F. Vandegrift at ANL (US) and successfully tested not only for US experiments but also for PNC (Japan) experiments. Hot tests of the TRUEX process were successfully completed in the US and Japan (PNC) in recent years. Carbamoylphosphine oxides (CMPO) known for their ability to remove actinides from high activity (HA) liquid waste are used in the TRUEX process. Horwitz showed that the actinides are included in complexes with several CMPO molecules (two to four). It seems interesting to synthesise molecules in which several CMPO moieties are combined in a suitable arrangement, this may lead to more efficient and selective extractant. Calixarenes bearing four diphenyl acetamido phosphine oxide functions on the upper rim, synthesised by Böhmer display at low concentration (10 -3 M) in nitrophenyl-hexyl-ether (NPHE) an higher extracting ability than CMPO used at a concentration ten times higher towards trivalent and tetravalent actinides [12]. In contrast to CMPO which displays low selectivity towards lanthanides, a strong decrease of lanthanide distribution coefficients is observed from 140 for lanthanum to 0.19 for ytterbium when calixarenes CMPO are used. One has to point out that this discrimination is suppressed when phenyl borne by phosphorus are replaced by hexyl groups [13]. Trialkyl phosphine oxide (TRPO) The TRPO process, developed by Zhu, Song et al. in Tsinghua University (China), is based on the use of liquid mixtures of TRPO soluble in aliphatic hydrocarbon diluent (kerosene) [14]. The affinity of the TRPO extractant for trivalent actinides and lanthanides is high for moderate aqueous nitric acid concentration (1 M) and low for high acidity (5 M), respectively. Consequently, the An+Ln TRPO extraction cycle is performed after neutralisation of the nitric acid in the feed to 1 M and the An+Ln mixture is stripped from the solvent using a HNO 3 = 5.5 M aqueous solution. The process was invented in the People’s Republic of China and successfully tested at the ITU of Karlsruhe with diluted HLLW solution. The decontamination factors for TRUs range from 10 3 to 10 4 in 1 M HNO 3 . In principle the method requires a slight acid reduction step but can operate in 1 to 2 M HNO 3 . The great advantage of the method is its reversibility in extraction and stripping, its miscibility with TBP and especially its loading capacity. However, the extraction requires additional separation steps similar to those described for TRUEX and DIDPA. Certain fission products (Zr, Mo, Ru and Tc) interfere with the separation. The presence of the high nitric acid concentration in the An+Ln mixture obtained after implementation of the TRPO process is a drawback for the subsequent An/Ln separation cycle, which requires rather low acidity for almost all the systems studied today (see below). The TRPO process (Figure II.5) was the subject of many developments in China as well as Europe at the ITU (Karlsruhe). The formation of secondary waste streams from the primary extraction process results mostly from the acid destruction and from the use of Na 2 CO 3 as solvent washing agent. It may be expected that the overall secondary waste volume will be higher than 10 000 l/tHM equivalent. 123
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TABLE OF CONTENTS EXECUTIVE SUMMARY
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TABLE DES MATIÈRES NOTE DE SYNTHÈ
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PART II. TECHNICAL ANALYSIS AND SYS
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4. IMPACT OF P&T ON RISK ASSESSMENT
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Figure II.31 Evolution of the expec
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Part II: Technical analysis and sys
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There are several scenarios which c
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eactor concepts are still in the co
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intermediate storage management, th
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1. INTRODUCTION 1.1 Involvement of
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and natural decay play an important
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Figure I.2 A schematic diagram of b
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Instead of recycling, one could ado
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to address there is the separation
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improvement of the biological shiel
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Figure I.3 A schematic diagram of t
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Figure1.5 A notional materials flow
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A few specific regulatory and safet
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• irradiation of FR-fuel in Fast
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dispersion in the geosphere or bios
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In the meantime the burn-up of spen
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Any reprocessing campaign of spent
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4. CRITICAL EVALUATION • P&T may
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5. GENERAL CONCLUSIONS • Fundamen
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NOTE DE SYNTHÈSE ET PORTÉE DU RAP
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Présentation générale Cette part
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courts. L’application de cette te
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éalisable, à condition d’augmen
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PREMIÈRE PARTIE : PRÉSENTATION G
Page 65 and 66: La troisième réunion internationa
Page 67 and 68: 1.5 Objectifs du rapport Dans l’e
Page 69 and 70: Figure I.1 Schéma de principe du c
Page 71 and 72: • l ’241 Am est le précurseur
Page 73 and 74: plutonium et environ 2 m 3 de déch
Page 75 and 76: 2.3 Technologie de fabrication des
Page 77: cadre de la coopération EFTTRA ont
Page 80 and 81: On peut voir sur la Figure I.4 les
Page 82 and 83: Figure I.4 Flux de matières dans u
Page 84 and 85: À court terme, les produits de fis
Page 86 and 87: Par conséquent, au cas où l’on
Page 88 and 89: De nombreux laboratoires dans le mo
Page 90 and 91: usé devrait représenter environ 3
Page 92 and 93: le nucléide le plus gênant est le
Page 94 and 95: transuraniens. Pour obtenir un taux
Page 96 and 97: On peut considérer des opérations
Page 98 and 99: devrait en principe ouvrir de nouve
Page 101: 5. CONCLUSIONS GÉNÉRALES • La m
Page 105: PART II: TECHNICAL ANALYSIS AND SYS
Page 108 and 109: 1.1.1.1 Minor actinides Americium a
Page 110 and 111: thus preventing its dispersion in t
Page 112 and 113: By contrast, information about the
Page 114 and 115: DIDPA [5] (see Figure II.3) process
Page 118 and 119: Figure II.5 TRPO process TRPO solve
Page 120 and 121: According to Jarvinen et al. in LAN
Page 122 and 123: curium. • Separation of americium
Page 124 and 125: 1.1.4.4 Separation of technetium an
Page 126 and 127: The second option is production of
Page 128 and 129: Figure II.9 Fuel cycle actinide bur
Page 130 and 131: Figure II.11 Flow sheet of pyro-rep
Page 132 and 133: The metathetical reaction between L
Page 134 and 135: This is confirmed by the radiotoxic
Page 136 and 137: For the same burn-up as in the pure
Page 138 and 139: planned for a burn-up range of 1.5
Page 140 and 141: On the basis of the study, it is no
Page 142 and 143: In a given reactor system, the diff
Page 144 and 145: - deterioration of the effectivenes
Page 146 and 147: Table II.5 Mass balances for homoge
Page 148 and 149: manufacture is 2 years. 12×24 targ
Page 150 and 151: Figure II.14 MA-loading methods in
Page 152 and 153: Table II.7 Mass balances for homoge
Page 154 and 155: Table II.8 Mass balances for hetero
Page 156 and 157: Core characteristics above: The fol
Page 158 and 159: Figure II.15 Concept of double stra
Page 160 and 161: Figure II.16 Concept of accelerator
Page 162 and 163: In Reference [99], the sodium coole
Page 164 and 165: In Germany, some small activities r
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OECD/NEA programmes The OECD/NEA Nu
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As a part of MA nuclear data evalua
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Table II.13 Pu and minor actinide b
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2.4.1.3 Transmutation in light wate
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3. DESCRIPTION OF CURRENT TRENDS IN
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The SPIN programme studied various
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• the RP1-2 scenario is compared
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Mass balance The MA mass balance, f
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4. IMPACT OF P&T ON RISK ASSESSMENT
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For deterministic effects, in the c
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• accounting for a number of safe
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Table II.17 Effective dose coeffici
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MOX fuel and recycling of recovered
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Figure II.22 Potential radioactivit
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Moreover, plutonium recycling and m
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Curium is assumed to be stored for
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Figure II.25 shows the radiotoxicit
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decrease is obtained in the radioto
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4.4 Risk and hazard assessment over
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4.4.2 Radiological impact of waste
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0.191 man-Sv/TWhe and the RFC with
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• conventional reprocessing does
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The maximum inventory of reactor co
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pursued. Since 137 Cs and 90 Sr are
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Figure II.26 Surface facilities. Ge
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Doses are controlled by 36 Cl up to
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Figure II.30 Overview of the canist
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surface. The reference repository i
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Figure II.34 Cavern-convection scen
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Figure II.36 Normal evolution scena
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considerable energy release as a re
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• taking into account the potenti
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• on the subject of transmutation
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[12] Arnaud-Neu, F., et al., “Cal
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Fuel”, Proc. Int. Conf. on Future
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[64] Arai, T., Suzuki, Y., Handa, M
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[88] Murata, H., and Mukaiyama, T.,
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[117] Gudowski, W., “Accelerator-
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[146] D’angelo, A., Marimbeau, P.
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[172] OECD/NEA and IAEA, Uranium: R
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[202] Schmidt, E., Zamorani, E., Ha
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