Technetium in Reprocessing of spent nuclear fuel

Technetium in Reprocessing of spent nuclear fuel

K.E.German

II Letnia Szkoła Energetyki i Chemii Jądrowej

The II Summer school of Energetic and Nuclear Chemistry

Biological and Chemical Research Centre UW 16-20 Sept., 2013

Technetium in

Reprocessing of spent nuclear fuel

K. E. G e r m a n

Russian Academy of Sciences

A.N. Frumkin Institute of Physical Chemistry and

Electrochemistry

Plan of the presentation

1. Tc and Re discovery, their abundance in the Earth crust

2. The main problems bonded to Tc …

3. And its solutions based on the fundamental studies in IPCE RAS

4. Development of separation technologies

5. Attempts of application (corrosion, metallurgy, catalysts).

6. Tc in Spent NF

7. Discussion: Spent Fuel Storage, Separate long-term storage or Transmutation

8. Improvements of separation technologies (SPIN-program (France), Adv.-ORIENT Cycle (Japan), PO Mayak- IPCRAS- Radium institute Russian program.

9. Scientific International collaboration of IPCE RAS with USA, France Japan and Poland

10. “Renaissance” of Transmutation program

43 Tc ⁹⁹ and Re in Earth crust

1937

C. Perrier and E. Segre Technetium (Z=43)

42 Mo ^А (d,n) ₄₃ Tc ^А+1

?

↔

1908

Prof. Ogawa (Japan) Nipponium

Confirmation in 1999: K.Yoshihara, ---

1925

V. Noddak , I. Taker, O.Berg Mazurium (Z = 43) in one (U,Re) ore

X-ray spectral and ICP MS Confirmation in 1988: P.H.M.Assche

(Molle, Belgium)

Re – the lowest natural abundance of all stable elements, Tc even less...

Usually we say – no Tc on the Earth, but : Tc natural concentration in earth crust 7 ^. 10 ^-8 %

¾ (Mo, Ru, Nb) cosmic rays → ⁹⁹ Tc (50 ton)

¾ ^235,238 U, ²³² Th (spontaneous fission) → ⁹⁹ Tc (50 ton)

¾Total Tc 100 ton naturally, plus: accumulation 10 ton per year in NPPs

Question arise : who discovered Tc? .

Our motivation for exploring Tc chemistry for the Closed Fuel Cycle

z Tc-99 is a key dose contributor at HLW repositories if TRU elements are greatly reduced by recycling

• long half-life of Tc (t _1/2 = 2.14 x 10 ⁵ years),

• high mobility, and solubility under oxidizing conditions

z Methods for managing the long-term threat of Tc to the environment

• Stable waste form/repository system providing with strict limits for Tc release over a long period of time (~1 million years?).

• Transmutation of radioactive Tc to stable Ru im

nuclear rectors.

Main problems of Tc

z Tc is important item in Nuclear Industry

z Tc redistribution in PUREX produces flows with long-lived high radioactive wastes

z Tc interferes at U/Pu separation stage in PUREX process

z Tc accumulation in High burn-up fuel together with Mo, Ru, Rh

z Tc in nuclear waste vitrification: Tc-Mo-

Ru metal phases, Tc(VII) volatility

Typical nuclear spent fuel

reprocessing involving PUREX

High level solid Tc/Mo/NM wastes dissolution and vitrification

Increasing burn-up in the SNF leads to lower oxidative potential – the metals like Mo, Tc, Ru forming mutual ε-phase (white inclusions) that is insoluble in nitric acid – formation of HLSW.

In vitrification of HLLW the same metals (Mo, Tc, Ru) are either volatile (oxic conditions) or forming metal ε-phase dendrites (reducing conditions) that lead to several furnace problems (Rokkasho-mura vitrification )

Investigation of these phases by means of X-ray,

diffraction, NMR, EXAFS and others could help

us in handling them

Another precipitating compound at SNF dissolution stage

No Technetium

inside

Experience and practice

Experience and practice

Experience and practice

Some examples of Russian experience in PUREX

improvement

• The first cycle flowsheet of RT-1 plant is essentially similar to the

THORP flowsheet but is

distinguished by more reliable joint stripping of Pu, Np, and Tc due to fairly low acidity.

• This is attained owing to introduction of a special cycle for separation of Pu and Np using large amounts of Fe(II);

• As a result, there are serious problems with evaporation of the raffinate of Pu-Np purification cyces and with localization of Tc in the high-level waste.

• [Zilberman, Radiochemistry 2008]

Classical Purex process weak-acid

Main problems : increasing burn-up leads to

Important interference by Tc at 2 extractor

Strong-acid mode of PUREX PROCESS

• MAIN PROBLEM :

• Interference by Tc at 2 extractor

• Uranium Product is contaminated with Tc

Russian reprocessing plant RT-1 , PUREX part

Separation of U from Pu in extraction reprocessing of WWER-440 and BN-600 SNF on the RT-1 facility (PA «Mayak») using the reductive

agent U(IV)+hydrazine, and the complexing agent (DTPA)

Russian reprocessing plant (RT-1, PO MAYAK, Ozersk)

z Main problem :

z DTPA complexes precipitation (Tc/ΔPu)

z Tc presents in all streams

Technetium interfering role in the PUREX Pu/U separation stage

Reductive separation of U, Pu, Np (Tc)

Reducing agent + complexing agent

Extract U,Pu,

Np (Tc(S _Tc ^{1st extcyc} =80 -90%))

Back extract Pu, Np (Tc(IV))

Extract U (Tc(VII))

1. Variable red-ox states 2. Variable species

z Difficulties in stability of U/Pu separation at UK, Russian and French facilities

z Catalytic Tc effects in many chem. reactions

z Variable Tc redox states

z Tc - Waste problems

z Tc-DTPA complex precipitation

DTPA – Tc : EXAFS

z Radiochemistry, 2011, Vol. 53, No. 2, pp. 178–185.

DTPA – Tc : EXAFS

MODEL STRUCTURES of Tc-DTPA (K.German, A. Melentiev, et all Radiochemistry, 2010-2011)

7

DTPA – Tc : EXAFS

French mode of PUREX

Process (UP-3 RP, La Hague)

Russian new design for RT-2 (GHK,Krasnoyarsk)

Never finished…

Prof. Zilberman and

colleagues : SUPERPUREX

(KHI, St-Petersburg/Gatchina)

Reducton of Np(V) by hydrazine in presence of Tc(VII) in 1.5 M

HNO ₃ (Tc catalytic effect)

0 20 40 60 80

0,0 0,1 0,2 0,3 0,4

D

time,min

Np (V)

Tc(IV)+Tc(X)

Np (IV)

Starting up

C(Np)=1,6*10 ^-3 моль/л, С(Tc)=1,15*10 ^-3 моль/л, C(HNO ₃ )=1,67 моль/л, C ₀ (N ₂ H ₅ NO ₃ )=0,3 моль/л,

t=45 ⁰ C,l=1 см

200 400

0,00 0,15 0,30

D

time,min

The end of the process Tc

Np (V) Np(IV) Gas evolut.

Np (V)+Tc(VII)

Some important features of liquid waste problems and its actual or

possible solutions

1. Tc redistribution in PUREX produces flows produces long-lived

high radioactive wastes

HLSW HLLW

2. Tc interferes at U/Pu partitionning stage in

PUREX process

Ways of improvement:

1. Improved PUREX: Additional step

inserted at E-P for Tc wash-out with 4M HNO3 (Fance, UK, Russia, Japan)

2. Move from PUREX to UREX (considered in USA)

3. Pyrometallurgycal reprocessing of high burn-up fuel (Russia, NIIAR -

Dimitrovgrad)

Ways of improvement:

1. Preliminary separation of Tc (Cogema, La-Hague)

2. Acidity control and soft reductors (RT-1, Ozersk)

3. Complexation of reduced Tc with DTPA or other complex forming agent (RT-1, Ozersk)

D E P U P (U/Pu) .

Pu

U

reductor

feed

USA - Advanced Fuel Cycle Initiative

z Goals of Advanced Fuel Cycle Initiative (AFCI)

separations technology program of GNEP (accord. :

• Preclude or significantly delay the need for a second geologic repository in this century

• Reduce volume and cost of high-level waste

• Separate TRU elements for fissioning in thermal or fast neutron-spectrum reactors

• Reduce the proliferation risk of the fuel cycle

• Facilitate Generation IV nuclear energy systems

z Aqueous-based liquid-liquid extraction technology is

baseline process because it is most mature - generic

name for process variants: UREX+

UREX+1a

Process Outline

TALSPEAK UREX

FPEX TRUEX

Lanthanide FPs

by G.Jarvinen and K.Czerwinski

U, Tc Cs, Sr

Non-Ln FPs Np, Pu,

Am, Cm

• Chop/dissolve fuel in HNO ₃ ; U and Tc separated in UREX step - TBP

in hydrocarbon solvent

• Cs/Sr extracted using

calix-crown and crown ether in FPEX process

• Transuranics and lanthanide fission products extracted in TRUEX step with CMPO, back- extracted with DTPA/lactic acid

• Transuranics and lanthanide

fission products separated

using TALSPEAK, di-2-ethyl-

hexylphosphoric acid extracts

lanthanides from actinides

Elaboration of separation methods and extensive fundamental studies

(by 1957 – 1977)

USA, Germany

z Boyd G., Cobble J., Parker G.

z C. Coleman et all (Oak Ridge, extraction with trilaurylamine)

z Rapp A.F.

z Davison S.A, Trop H., Cotton F.A.

z Schwochau K.

Russia, Czechoslovakia

z V. Spitsyn, A. Kuzina,

(extraction with acetone, ion exchange)

z V. Shvedov, Kotegov, later - G. Akopov, A.

Krinitsyn (extraction, ion exchange)

z L. Zaitseva, V. Volk

(crystallization and other)

z Arapova, Yu. Prokopchuk, G. Chepurkov (extraction, ion exchange)

z Macasek F., Kadrabova

(Slovakia)

Industrial scale

separation of Tc-99g

Five main approaches were elaborated,

each one has its advantages and disadvantages

z Precipitation \ co-precipitation

(USA, Russia)

z Selective gas adsorption

(USA, Kentucky)

z Anion exchange (USA, Russia)

z Adsorption at carbon (Japan)

z Liquid-Liquid Extraction (USA, Russia, France, Japan)

Separation of Tc from HAW of gas-diffusion plant in USA

z Back side : releases of Tc from decommissioned plant Airborne radionuclides discharged at

Portsmouth, 1989-1993 (ORNL-DWG 94M-8261)

0 2 4 6 8 10

1989 1990 1991 1992 1993 Year

CURI ES

URANIUM TECHNETIUM

z Separation of Tc as TcF ₆ was made with MgF ₂ filters at 125 ^o C in 1960 – 1963 from HAW of gas-diffusion plant in Kentucky, USA

(Total = 25 kg Tc)

Tomlinson, Judson,

Zahn, ICPUAE,1964

The reaction of the cascade relevant technetium fluorides

with water

z “ … A signifcant number of anecdotal reports of "pouring Tc" from cascade instrument lines exist. Observations of a finning, viscous

brownish-red material with high beta activity suggests the presence of this acid, or perhaps a mixture of it, in low(er) temperature copper lines.

HTcO, has a relatively low vapor pressure (61 torr at 100 ^O C) at

temperatures typical to the cascade, 21 and could also easily migrate as a gas phase compound”

/ D. W. Simmons. An Introduction to Technetium in the Gaseous Diffusion Cascades. Technical report K/TSO–39. Oak Ridge, Tennessee, USA -

September 1996 /

Development of ion-exchange technology for Tc separation

in IPCE RAS (1971-1976)

Prof. A.F. Kuzina (Tc Group leader till 1985 ) presents her

Tc samples prepared in the Institute from the concentrate

separated from radioactive wastes generated at

Krasnoyarsk Reprocessing Plant to

Glean SEABORG (1978)

Separation of macro

amounts of Tc-99g in USSR

9 1 kg of Tc was converted to metal in hot cell of IPCE RAS and distributed among different Russian institutes

9 In 1971-1976 IPC RAS in collaboration with Krasnoyarsk Mining Enterprise has separated from HAW some kilograms of K ⁹⁹ TcO ₄

9 In 1983 -1986 collaboration of PO

“Mayak”, IPCE RAS and Radium Institute resulted in elaboration of anion-exchange technology for Tc separation and 40 kg of K ⁹⁹ TcO ₄ . This work was awarded with the special Diploma of the Russian authorities

™ Anna KUZINA and Victor SPITSYN analyzing the

sample of Tc metal

Some new Tc(VII) compounds synthesised in IPCE RAS and NLVU for reprocessing of SNF

N New compound of Tc or Re Structure C solubility 25°C, M/L ^ρ Kass

1 Tetrapropylammonium pertechnetate ^Pna2

a = 13.22(4), b = 12.35(3), c = 10.13(4) Å

(8.7 ±0.2)

10 ^-3 1,26 2,6 ± 0,4

2 Tetrapropylammonium perrhenate ^Pna2

a = 13.169(2), b = 12.311(2), c =

10.107(1) Å

(8.9 ±0.2)

10 ^-3 1.57 2,5 ± 0,3

3 Anilinium pertechnetate ^P2

/c 9.8388(2)

5.89920(10) 14.6540(2) Å (7.9 ± 0.2)

10 ^-2 2.07 -

4 Anilinium perrhenate ^P2

/c 9.8714(4)

5.9729(2) 14.6354(5) (8.3 ± 0.2)

10 ^-2 2.7 -

5 Tetrahexylammonium perthechnetate ^- (7.1 ± 0.5)

10 ^-5 1,07 40 ± 5

6 Tetrapentylammonium pertechnetate ^- (8.0 ± 0.2)

10 ^-4 1.33 -

7 Threephenylguanidinium pertechnetate ^P-1 9.87(1) 14.09(1) 15.44(1)

99.6 101.8 95.4

(3.9 ± 0.3)

10 ^-3 1,3 -

8 LiTcO ₄ *3H ₂ O ^P6

mc, a=7.8604(1) b=5.4164(1) A

5. 1 9 [(NpO ₂ ) ₂ (TcO ₄ ) ₄ *3H ₂ O] _n P-1 5.322(5) 13.034(7)

15.46(9) 107.08 98.05 93.86(6)

0.95 4.99

New compounds (continued)

N New compound of Tc or Re ^Structure C solubility 25°C, M/L ^ρ Kass 11 Tetraphenylphosphonium

pertechnetate

a=17.25(5) b =17.26(5)

c =14.239(5) (4.0 ±0.2)

10 ^-4 ~1,1 40 ± 5

12 Cetylpyridinium pertechnetate ^- (3.9 ± 0.3)

10 ^-3 ~1,12 - 13 Cetylthreemethylammonium

pertechnetate

- (6,8 ± 0.5)

10 ^-3 ~1,15 -

14 Guanidinium pertechnetate a=7,338(2) A b=7,338(2) A

c=9,022(4) A γ=120

(9.7 ± 0.3)

10 ^-2 2,30 -

15 Guanidinium perrhenate 4.9657(4) 7.7187(7)

8.4423(7) α=75.314(4)

(7 ± 0.5)

10 ^-2 3,30 16 Dodecylthreemethylammonium

pertechnetate

liquide (4.0 ±0.2)

10 ^-5 ~1,05 -

Some other new interesting compounds have been

made by K.Czerwinski and co-workers in 2007- 2013

A few examples of new Tc compound structures made in IPCE RAS

(K.German, M.Grigoriev, A.Maruk etc.)

[Anil-H]TcO ₄ [GuH]ReO ₄

LiTcO ₄ *3H ₂ O [Bu ₄ N]TcO ₄

[(AnO ₂ ) ₂ (MO ₄ ) ₄ *3H ₂ O] _n , (An = U, Np; M = Tc, Re)

[Pr ₄ N]TcO ₄

[Tc ₂ Ac ₄ ](TcO ₄ ) ₂

Pyrochemical reprocessing of BN-1200 SNF

(PRORYV project, Russia, 2020)

z Tc behavior not well studied

z Na ₂ TcCl ₆ + Li ₂ TcCl ₆ eutectic

z Reducing cond.: ε-phases

z Oxidizing cond.:

z TcO ₃ Cl, …

Top of the fundamental studies on Tc in IPCE RAS 10 (!) oxidation states were found for

Tc in HX (X = Cl, Br, I) :

7+, 6+, 5+, 4+, 3+, 2.5+, 2+, 1.83+, 1.66+, 1.5+

1. 3-gonal-prismatic Tc chlorides and iodides ( 2 clusters of Tc(1.83+) and Tc(1.66+) : (Me ₄ N) _x [Tc ₆ (m-Cl) ₆ Cl ₆ ]Cl _y ) (K.German and others)

2. 4-gonal-prismatic Tc cluster bromide (addition of Tc ₂ X ₂ to (1) S.Kryutchkov)

3. octahedral Tc cluster bromides and iodides (angular conversion of (1))

а

в

1 2 3

Each synthesis involve up to 10 g of Tc !

Structures: unique in inorganic chemistry

A Trigonal-Prismatic Hexanuclear Technetium(II) Bromide Cluster

Na(Tc ₆ Br ₁₂ ) ₂ Br

z Solid-State Synthesis

z E.V. Johnstone, D.J. Grant, F.

Poineau, L. Fox, P. M. Forster, L. Ma, L. Gagliardi, K. R.

Czerwinski, A. P. Sattelberger

GAS-PHASE TRANSPORT ? … !

My vision :

it’s the world scale research of the year . Three Profs. Czerwinski

all – radiochemists!

Some important gaps in our knowledge of Tc chemistry and thermodynamics

1. Tc metal: No heat capacities for Tc(cr) above 15, thermodyn.

stability of the cubic Tc metal at nano-scale.

2. No heat capacities and entropies for TcO ₂ (cr) and Tc ₂ O ₇ (cr).

3. Poor characterization of TcO ₃ , Tc ₂ O ₃ , Tc ₄ O ₅ and TcO ₂ *nH ₂ O 4. Poor characterization of Tc

sulfides (possible solubility

limiting phases under reducing conditions) and carbides

(alternative nuclear fuel)

5. Inconsistence of different experimen- tal data on TcO ₂ *nH ₂ O solubility as function of pH (colloid speciation) 6. Poor definition of the protonation

constant for HTcO ₄

7. Almost no equilibrium complex

formation constants between Tc(III), Tc(IV) and Tc(V) and even most of the common inorganic anions

present in groundwater

8. Inconsistence of stability estimations for Tc(IV) and Tc(V) from

environmental and

radiopharmaceutical studies

After J. Rard with some modifications

International collaboration of IPCE RAS with DOE and

Nevada University (USA)

¾ Tc reduction, co-precipitation studies and U- corrosion studies on decontamination of HAW tanks at Hanford Site (V. Peretrukhin, K. German in 1995-2007)

¾ Tc co-precipitation with cancrinite, sodalite,

cryolite, oxalate and brown sludges with respect to decontamination of HAW tanks at Savannah River Sites. Fe(II) and Mn (III) oxides were

effective Tc carriers and underwent chemical transformations on ageing that increased

leaching resistance to most agents

(K. German, 1999 – 2000, under contract with US DOE)

¾ EXAFS and NMR study of Tc

¾ in concentrated acid solutions

¾ (Nevada Univ.& IPCE, 2010 ) X-ray pattern of simulated

Component of brown sludge of SRS HAW Tanks

99 Tc-NMR shift vs. TcO ₄ ^- of KTcO ₄

in 3 M to 18 M H ₂ SO ₄ .

99 Tc concentrations found in various tank sludges at SRS

Tank Number

[Tc-99], mCi/g dried

solids Reference

17 0.462 d'Entremont et

al. 1997 20, white

solids 0.34 d'Entremont and Hester 1996

20, brown

solids 0.94 d'Entremont and Hester 1996

42 0.22 Hay 1999

51 0.21 Hay 1999

8 0.22 Hay 1999

11 0.34 Hay 1999

The discovery of relatively high

99 Tc concentrations in

inorganic mineral sludge heels taken from some tanks at the US-DOE Savannah River Site

(SRS) has prompted investigations of Tc uptake

from alkaline highly active waste (HAW) by solid

adsorbents

The SRS waste volumes (Table 2.4 of "Integrated Database Report - 1993: S.Spent Fuel and Radioactive

Waste Inventories, Projections, and Characteristics,”]

Tc-99 quantities (Table 2.11), and

Volume, Tc-99, Ci [Tc-99], [Tc], 10

Kd

liters Ci/liter g/liter total

Liquid 61.4 1.68E+04 2.74E-03 0.162 -

Sludge 13.9 1.14E+04 8.20E-03 0.483 3

Salt Cake 53.8 2.78E+03 5.17E-04 0.0305 0.2

Overall waste 129.1 3.098E+04 2.40E-03 0.141 -

Question was: Which components absorb Tc with K _d higher than 3 and are resistant to leaching?

Tc-99 concentrations

calculated from these data

Sludge components as

carriers for Tc(VII) and Tc(IV)

. SODIUM OXALATE . Na2C2O4

. CRYOLITE . Na3AlF6

ALUMINOSILICATES CANCRINITE

SODALITE WHITE SOLIDS

. PLATINUM GROUP . METALS

Rh, Ru, Pd

METAL HYDROXIDES (Fe, Cr, Mn)(O)(OH)

BROWN SOLIDS

SOLID SLUDGE COMPONENTS

TiO ₂ was also tested

Experimental conditions for precipitation and leaching tests:

Precipitation tests:

¾ Wastes are alkaline

¾ Tc is redox sensitive

¾ Sharp differences in the redox potential within the tanks are observed,

So, both:

¾ oxidizing [Tc(VII)]

¾ and reducing [Tc(IV)]

¾ conditions were tested in 0.1- 5 N NaOH + 0-5 N NaOH.

Leaching modes:

¾ Surface leaching.

¾ Complete dissolution.

Leaching agents

¾ all precipitates : 0.1N NaOH

¾ aluminosilicates - NaHF ₂

¾ Na oxalate - 0.1N NaOH, NaNO ₂

¾ FeOOH - 0.1N NaOH, H ₂ O ₂

¾ MnOOH - 0.1N NaOH, H ₂ O ₂

¾ TiO ₂ - 0.1- 3N NaOH

Methods: Liquid scintillation counting (LSC) of solutions, XRD, NMR, IR

Study of Tc uptake with

Aluminosilicates under oxidizing conditions at 70-130 ^o C

Solution Formed solid Kd

10

-10

M Tc 0.2-5M NaOH

0.5-5 M NaNO3 Cancrinite less 1 10

-10

M Tc

0.2-5M NaOH

NaNO3 free Sodalite less 1

¾ TcO ₄ ^- is too large and therefore it is excluded from the

aluminosilicate structure in both

cancrinite and sodalite

¾ Literature data have demonstrated the

possibility of ClO ₄ ^- and MnO ₄ ^- co-crystallisaton with aluminosilicates : purple

Na ₈ [AlSiO ₄ ] ₆ (MnO ₄ ) ₂ (Weller,1999 etc.)

OUR EXPERIMENTS on TcO ₄ ^- (reaction: NaAlO ₂ +Na ₂ SiO ₃ +NaOH)

Case of Aluminosilicates formed in concentrated Tc(VII) solution

¾ [Tc] = 0.2 M

¾ in NaNO3 solutions - cancrinite

¾ in NaNO3-free solutions - sodalite

¾ Although NMR spectrum presented shift typical for coordinated Tc(VII) its

concentration is very low

¾ Dissolution in NaHF ₂ and LSC has shown : [Tc] in solid

cancrinite was 57 mg/kg ~ 100 times less than in initial

solution

Fig. 1. NMR-⁹⁹Tc spectrum of the aluminosilicate containing 57 mg-Tc/kg. Tc spectrum presents evidence for -30 ppm shift

characteristic of coordinated pertechnetate

Study of Tc uptake with

Aluminosilicates under reducing conditions (0.2M N ₂ H ₅ Cl, 1M NaNO ₃ , T = 80 ⁰ С, t = 3 d)

Precipitation of

cancrinite↓ Leaching conditions:

NaOH M Tc yield,

%

Leaching

agent: T,

o C Leaching yield , Tc, % hour 3 1 day 10

2.0 18.9 1M NaOH 20 0.8 1 days 3.7

4.0 32 2M NaOH 20 0.8 1.2 2.0

2.0 25.2 0.1M NaOH +

0.25 M H ₂ O ₂ 60 25 26.9 27

2.0 18.9 0.1M NaOH +

0.5 H ₂ O ₂ 18 4 6.9 7

4.0 32 0.1M NaOH +

0.5 H ₂ O ₂ 18 6.5 6.9 11

¾ Under reducing conditions Tc uptake is important

¾ Tc(IV) in aluminosilicates is resistant to leaching

Study of Tc(VII) sorption by crystalline TiO ₂

under oxidizing conditions

¾ Tc(VII) was sorbed by TiO ₂ from neutral solution with K _d

= 30 ml/g.

¾ However, the K _d at pH=10 was only 3.3 ml/g

¾ No affinity to Tc(VII) was noted for TiO ₂ at pH=12 and higher .

¾ Among the minerals tested for Tc(VII) uptake, high-

density TiO ₂ was the most

efficient

MST and Silicotitanates yet

not tested ..?

Study of Tc uptake with Na oxalate under

oxidizing and reducing conditions

¾ Tc(VII) is excluded from the Na oxalate structure under oxidizing conditions (Kd

= 1-2)

¾ Under reducing conditions Tc(IV) forms a separate TcO ₂ *1.6H ₂ O phase - no interaction between Tc hydroxide and Na oxalate were detected

¾ Tc precipitate is not resistant to leaching with 0.1 N NaNO ₂ NaOH + H ₂ C ₂ O ₄ = Na ₂ C ₂ O ₄

X-ray diffraction tests :

the precipitate is

sodium oxalate Na ₂ C ₂ O ₄

(PDF#20-1149)

Study of Tc uptake with Cryolite Na ₃ AlF ₆ under

oxidizing and reducing conditions

¾ Reduced Tc :

¾ 17-35% of Tc(IV) as TcCl ₆ ^2- is co-precipitated with cryolite

¾ N ₂ H ₅ NO ₃ inhibits co- precipitation

¾ Oxidizing conditions:

¾ Kd is less 1

¾ Tc(VII) is excluded from cryolite

structure 6F ^- +NaAlO ₂ +Na ₂ CO ₃

X-ray diffraction tests :

the precipitate is cryolite Na ₃ AlF ₆

Tc(IV) uptake with Cryolite Na ₃ AlF ₆

under reducing conditions

N o [NH ₄ F]

initial, M

[Na ₂ CO ₃ ] in final solution, M

[N ₂ H ₅ NO ₃ ], in final solution, M

Tc(IV) uptake,

% 1 2

3 4 5 8 10 9

2,0 2.5 3.0 4,0 6,0 2,0 2,0 2,0

0,6 0.6 0,6 0.6 0,6 0,4 0,8 0,6

- - - - - - 0,1 -

20 23 26 28 35 25 17 0

• Tc(IV) is added as Na ₂ TcCl ₆ to (NH ₄ F+NaAlO ₂ ) solution

• No additional reducing agent in exp. No 1-9

• Leaching test were impossible to quantify relative to real cryolite

in tanks as complete peptization occurred.

Study of Tc(IV) uptake with

FeOOH under reducing conditions

Precipitation test: Leaching test (t=18 ^o C, d = days):

NaOH M

Tc in solid phase, %

Leaching agent:

Leaching yield ,Tc, % 1 d 10 d 29 d 105d

0.6 97 0.1M NaOH 1.0 9.8 14.9 24 2.0 88.0 1M NaOH 2.9 16.5 40.2 58 4.0 90 2M NaOH 0.8 2 3 8.2

¾ Reducing agent: 0.02M FeSO4, T = 60 ⁰ С, time = 3 h

¾ Precipitate : FeOOH/Fe ₂ O ₃

Though Tc adsorbed better on iron hydroxides from 0.5–2.0 M NaOH than from 3.0-4.0 M NaOH, the precipitates formed at lower NaOH

concentration were more easily leached by the NaOH leachant

Tc leaching with H ₂ O ₂ was 20 % and with Na ₂ S ₂ O ₈ was70-100% in 100

days

Study of Tc(IV) uptake with MnOOH under reducing conditions

¾ Reaction NaOH + Na ₂ MnO ₄ + N ₂ H ₅ OH= MnOOH X-ray diffraction tests : the freshly precipitated

solid was Mn ₂ O ₃ , the aged precipitate was manganite MnOOH (PDF#18-805)

¾ Manganese(III) oxides were effective Tc carriers and underwent chemical transformations on ageing that increased leaching resistance to most agents.

MnOOH precipitation MnOOH leaching to 0.1 NaOH (1,3,4) and Na ₂ S ₂ O ₈ (2)

Tc & HLW Vitrification

z Tc is volatilized at 750 – 850 ^o C under oxidizing conditions as

MTcO4 (M = Na,

Cs)

Russian Tc - Transmutation program (1992-2003)

---

99 Tc(n,γ) ¹⁰⁰ Tc(β) ¹⁰⁰ Ru

0,00%

25,00%

50,00%

75,00%

1 2 3 4 5

Irradiation time, days

T ec hneti um- 99 B ur nup, %

Hanford (USA) 1989

Wootan W Jordheim DP Matsumoto WY

Petten (NL) 1994-1998 Konings RJM Franken WMP

Conrad RP et al.

Dimitrovgrad (Russia) IPC RAS - NIIAR

1999 - 2000 Kozar AA Peretroukhine VF Tarasov VA et al.

6%

18%

34%

65%

10.5 days 193 days 579 days 72 days 260 days 0,67 %

= Pessimistic

Tc transmutation experiment (IPCE RAS – NIIAR, 1999-2008) In IPC RAS a set of metal disc targets (10x10x0.3 mm) prepared

and assembled in two batches with total weight up to 5 g.

Transmutation experiment was carried out at high flux SM-3 reactor ( NIIAR, Dimitrovgrad )

2nd batch: F _t > 2× 10 ¹⁵ cm ^-2 s ^-1 1st batch: F _t =1.3× 10 ¹⁵ cm ^-2 s ^-1

99 Tc burnups have made:

34 ± 6 % and 65 ± 11 %

for the 1st and 2nd targets batches

™ _{The high} ⁹⁹ ---- _{Tc burn-up} s were reached and about 2.5 g of new matter - transmutation ruthenium were accumulated as a result of experiments on SM-3 reactor

™ These values are significantly higher of burnups 6 and 16 % achieved on HFR in Petten earlier

1 − центральный блок трансурановых мишеней; 2 − бериллиевые вкладыши;

3 − бериллиевые блоки отражателя; 4 − центральный компенсирующий орган

− автоматический регулятор

− стержень аварийной защиты

− ячейка активной зоны с Т ВС

− компенсирующий орган

− канал и его номер

7 Д-2 81

КО-91

АР 3 4 2

1

Д-3 Д-1

9 12

56 46 66 76 86 96

65

75 55 45

85 95

42 52 62 72 82 92

51 41 61 71 81

44 54 84

94

43 53 83

93 КО3 КО4

91 КО1 КО2

Д-2 2

6

14 15

3

7 8

16

Д-4 Д-5 17 АР

Д-6

Д-10 Д-9

13 Д-8

АР1 19

4 10

Д-7 5

20

11 21

18

Рис.5. Картограмма реактора СМ

Preparation of artificial stable Ruthenium by transmutation of

Technetium

z Rotmanov K. et all. Radiochemistry , 50(2008)408

z New Ruthenium is almost monoisotopic Ru-100

z It has different spectral properties

z It is available only to several countries that develop nuclear industry

z Tc target material:

z Tc metal powder / Kozar (2008)

z Tc – C composite Tc

carbide / German

(2005)

The IPCE publications used in the presentation

z The principle achievements of recent Russian researches in technetium chemistry, metallurgy, environmental science, nuclear reprocessing and applications are overviewed. The allied aspects of rhenium chemistry and applications are compared. The progress in technetium handling during the spent nuclear fuel reprocessing was based on the fundamental studies of numerous new technetium mono- and polynuclear compounds and species [1-10]. The previous achievements were reviewed in [11].

z In concentrated water solutions Tc(VII) often forms crystals isomorphous with perchlorates while in concentrated unhydrous solutions Tc(VII) behaviour is more similar to Re(VII) compared to Cl(VII) [4-6].

z Interesting results were obtained with the Tc-DTPA complex formed under advanced PUREX conditions [6-7]. Great progress have been achieved in the understanding of Tc(VII) behaviour in acids [8-10] that is important for explanation and prediction of Tc and Re handling in acids, including the concentrated acid solutions up to highest. The investigation in crystal structures of Tc compounds [2] enabled us with direct recommendations for the template synthesis for Tc and Re sensors [6]. The progress in Tc carbonyl compounds gave chance for advanced Tc metal and Tc carbide films deposition [7]. Technetium sulphide and rhenium were studied both with respect to medicine and to environmental behaviour of these elements [11]. The work on technetium nanomaterials was carried in Russia in 2009-2010 within RFBR-09-03-00017, while the work on DTPA complexes with RFBR-09- 08000153.

z References.

z Peretrukhin V.F., German К.E., Маslennikov А.G. etc. Development of chemistry and technology of technetium. In.: «Modern problems of physical chemistry» р. 681 – 695. М.: «Granitsy Publ.» (2005) 681-695.

z Grigoriev M.S., German K.E., Maruk A.Y. // Acta Crystallogr. Sect E. (2007) V. 63. Pt.9. : P. m2061, and p. m2355.

z Maruk A.Y. Grigoriev M.S., German K.E. Russ. Coord.Chem(2010) v.36, No 5, pp. 1–8.

z Maruk A.Y. Grigoriev M.S., German K.E. Abstracts of the ”Conference on diffraction methods for substance investigations: from molecules to crystals and nanomaterials”, Chernkgolovka. 30 june-3 july 2008. p.

z Maruk A.Y. Grigoriev M.S., German K.E. Abstracts of the ”Conference on diffraction methods for substance investigations: from molecules to crystals and nanomaterials”, Chernkgolovka. 25 june- 28 june 2010. p.

z D.N. Tumanova, K.E. German, V.F. Peretrukhin, Ya.A. Obruchnikova, A.Yu. Tsivadze. Stabilization and spectral characteristics of technetium and rhenium peroxides. In: 6-th International Symposium on Technetium and Rhenium. NMMU-Port Elizabeth, 7-10 October 2008, p.47.

z D.N. Tumanova, K.E. German, V.F. Peretrukhin, A.Yu. Tsivadze. Formation of technetium peroxydes in anhydrous sulfuric acid.

Doklady Phys. Chem.420 (2008) 114-117.

z German K.E., Melentiev A.B., Kalmykov S.N., etc. Tc-DTPA sediments formed in technetium – hydrazine – DTPA – nitric acid solutions. Journ. Nucl. Medcine and Biol.(2010). Sept. pp.

z B.Ya. Zilberman. Radiochemistry ,42 (2000) 1-14.

z Katayev E.A., Kolesnikov G.V., Khrustalev V.N. etc. // J. Radioanal. Nucl. Chem.(2009) 282: p. 385–389.

z Maruk A.Y., German K.E., Kirakosyan G.A. etc. HtcO4. Abstracts of the 6-th Russian conference on radiochemistry, 12-16 Oct.

2009. Moscow. p.

z F. Poineau, Ph. Weck, K. German, A. Maruk, G. Kirakosyan, W. Lukens, D. B. Rego, A. P. Sattelberger, K. R. Czerwinski . Speciation of Heptavalent Technetium in Sulfuric Acid: Structural and Spectroscopic Studies. RSC-Dalton Transactions(2010) Dec. pp. (in press).

The IPCE publications used in the presentation (continued)

z Peretrukhin V.F., Moisy Ph., German K.E. etc. J. de la Soc. de Chim. D.I. Mendeleiev (2007) v.51, № 6, p.11-23.

z Plekhanov Yu.V., German K.E., Sekine R. Electronic structure of binuclear technetium chloroacetate cluster: quantum Chemical calculations and assignement of optical and XPE spectra. Radiochemistry, 45 (2003) 243-249.

z German K.E., Kryutchkov S.V. Polynuclear technetium halide clusters. Russ. Journ. Inorg. Chem. 47 (2002) 578-583.

z N. N. Popova, I. G. Tananaev, S. D. Rovnyi, B. F. Myasoedov, Russ. Chem. Rev., 72 (2003) 101.

z German K.E., Peretrukhin V.F., Gedgovd K.N., etc.// Journ. Nucl. Radiochem. Sci. 6 (2006) No.3, pp. 211-214.

z Alekseev I.E., Antropov A.E. Accelerated transport of impurity Tc-99m atoms at polymorph transition in irradiated metal molybdenum. Radiochemistry, 44 (2002) 334-336 (Rus).

z Sidorenko G.V., Miroslavov A.E., Suglobov D.N. Vapor deposition of technetium coatings by thermolysis of volatile carbonyl complexes : II. Chemical and phase composition, microstructure, and corrosion resistance of coatings. Radiochemistry, 51 (2009) 583-593.

z K.E. German, Yu.V. Plekhanov. // Quantum chemical model of Technetium Carbide. Journal of Nuclear and Radiochemical Sciences (2006) V. 6, No.3, pp. 215-216.

z A.B. Melent’ev, V.A. Misharin, A.N. Mashkin, I.G.Tananaev, K.E.German. Abstracts of the 6-th Russian conference on radiochemistry, 12-16 Oct. 2009. Moscow. p. 209.

z D.N.Tumanova, K. E. German, Ph. Moisy, M. Lecomte, V. F. Peretrukhin. Catalytic effects of Tс ions on the Np -hydrazinium - nitric acid system. In: Abstracts of the 6-th International Symposium on Technetium and Rhenium. NMMU-Port Elizabeth, 7-10 October 2008, p.46.

z German K. E., Dorokhov A. V., Kopytin A. V., etc. // Journ. Nucl. Radiochem. Sci. (2006) V. 6, No.3, pp. 217-220.

z German K.E., Kosareva I.M., Peretroukhin V.F., etc. In: Proceedings of the 5-th Int.Conf. on radioactive wase management and environmental remediation. ICEM'95. V.1. Cross-cutting Issues and management of high-level waste and spent fuel. (Eds.: S.Slate, Feizollahi, C.Creer), NY(1995) p. 713 - 722.

z Slobodkin A.I., Tourova T.P., German K.E., etc. Int. Journ. System. Evolut. Microbiol.(2006). V. 56. P. 369-372.

z Tarasov V.P., Muravlev Yu. B., German K.E., Popova N.N. Tc-99 NMR of Technetium and Technetium-Ruthenium nanoparticles. In:

Magnetic Resonance in Colloid and Interface Science. Edited by Jacques P. Fraissard and Olga Lapina. Book Series: NATO Science Series: II: Mathematics, Physics and Chemistry: Volume 76. Kluwer Academic Publishers. Netherlands (2002) Pp. 455- 468.

z Pirogova G.N., Panich N.M. Physicochemical properties of Technetium.Russ. Journ. Inorg. Chem. 47 (2002) 681-687.

z Maruk A.Ya., Khaustova T.A., German K.E. etc. Labeling conditions study for technetium-99m thiosemicarbazid derivatives.

School-conference on radiochemistry 2010 Ozersk.

z German K.E., Obruchnikova Ya.A., Popova N.N. etc. Abstracts of All-russian conference ” Physico-chemical aspects of nanotechnology – properties and applications”. Moscow, L.Ya. Karpov Institute of Physical Chemistry. 2009. P.

z German K.E., Popova N. N., Tarasov V.P., etc. Journ. Russ. Chem. Soc. Mendeleev, (2010) Sept.No. pp. (in press).

z Peretrukhin V. F., Rovnyi S. I.,. Ershov V. V, German K. E., Kozar A. A., Russ. J. Inorg. Chem., 47 (2002) 637.

For conclusion:

OUR MODERN VISION oF Tc-99 FATE :

Born to Burn

And this fire will give not ash

but the noble metal