A review of corrosion issues related to uranyl nitrate base aqueous homogeneous reactors

Abstract

Aqueous homogeneous reactors (AHRs) are liquid fuel nuclear reactors, typically consisting of an acidified nitrate or sulphate base solution of enriched uranium-235 (²³⁵U). The goal of this paper is to review both the report and research literature on the topic of materials corrosion issues related to uranyl nitrate base AHRs. The materials of interest are stainless steel (SS)347, SS304L, SS304L-NAG, SS316L and zirconium (Zr) base alloys. In nitric acid solutions, SS and Zr alloys are passive, although there is some increased susceptibility of SS347 to intergranular corrosion (IGC) and knife-line attack as compared to other alloys. This is likely a result of the higher carbon (C) content in SS347. In uranyl nitrate fuel simulants corrosion rates increased as compared with nitric acid alone with the corrosion rate of SS347 being the highest while SS316 was the lowest of the austenitic stainless steels tested. In comparison, corrosion rates of Zr based alloys remained relatively unchanged in uranyl nitrate base solutions. The most prominent issue for these materials appears to be iodide (I⁻) induced pitting corrosion on the walls of the off-gas extraction system with the potential for stress corrosion cracking. For Zr alloys, vapour phase I⁻ pitting and SCC are well documented failure mechanisms with the threshold I⁻ concentration being on the order of 1-2 ppm. In the off-gas extraction system of a 200 kW AHR calculations indicate that the I⁻ concentration may be as high as 0·4-0·6 ppm warranting further study in this area. The influence of a prototypic AHR neutron flux on corrosion rates and susceptibility to underfilm corrosion, due to precipitation of UO₂(OH)₂, was not available from the literature.

Keywords

AQUEOUS HOMOGENOUS REACTORS AHR CORROSION NITRIC ACID URANYL NITRATE STAINLESS STEEL ZIRCONIUM

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References

Bunker

M. E.

: ‘Early reactor: from Fermi’ water boiler to novel power prototypes’ LA-UR-83-5072, Los Alamos National Laboratory Los Alamos, NM, USA 1983.

Homogeneous Aqueous Solution Nuclear Reactors for the Production of Mo-99 and other Short Lived Radioistotopes, IAEA-TECDOC-1601 Nuclear Fuel Cycle and Materials Section International Atomic Energy Agency

Vienna, Austria

2008.

Barbry

and Fouffland

: Proc. Conf. on ‘Topical issues in nuclear safety’134; 2001

Vienna

IAEA.

Nakajima

Yamamoto

and Miyoshi

: J. Nuclear Sci. Technol 2002 39 1162.

Cheng

and Deng

: Proc. Homogeneous Aqueous Solution Nuclear Reactors for the Production of Mo-99 and other Short Lived Radioistotopes; 23; 2008

Vienna

IAEA.

Sedriks

A. J.

: ‘Corrosion of stainless steels’2nd edn; 1996

New York

Wiley-Interscience.

Armstrong

R. D.

Cleland

G. E.

and Whillock

G. O. H.

: J. Appl. Electrochem., 1998 28 1205.

Gladman

: Mater. Perform., 1989 28 60.

Dillon

C. P.

: Corrosion 1956 12 47.

10.

Mudali

U. K.

Dayal

R.K.

and Gnaamoorthy

J.B.

: J. Nucl. Mater., 1993 203 73.

11.

Shankar

A. R.

Raju

V. R.

Rao

M. N.

Mudali

U. K.

Khatak

H. S.

and Raj

: Corros. Sci., 2007 49 3527.

12.

Kain

Sengupta

P. K.

and Banjee

: Metall. Mater. Trans. A 2005 36A 1075.

13.

Kain

Shinde

S. S.

and Gadiyar

H. S.

: J. Mater. Eng. Perform., 1994 36 699.

14.

Beavers

J. A.

Griess

J. C.

and Boyd

W. K.

: Corrosion 1981 37 292.

15.

Kajimura

and Nagano

: Corrosion 1992 48 391.

16.

Yau

T. L.

: Corrosion 1988 44 745.

17.

Kolman

D. G.

Ford

D. K.

Butt

D. P.

and Nelson

: Corros. 1997 39 2067.

18.

‘Nuclides and isotopes’, 15th edn, ‘ Chart of the Nuclides’; 1996

San Jose

CA, General Electric Co. and KAPL.

19.

Bunker

M. E.

: Status Report on the Water Boiler Reactor, LA-2854

Los Alamos National Laboratory

Los Alamos, NM, USA

1963.

20.

Busey

H. M.

and H:

R.H.

‘ Corrosion of stainless steels by water boiler fuels’, LA-3101

Los Alamos National Laboratory

Los Alamos, NM, USA

1964.

21.

Savage

H. C.

Jenks

G. H.

and G:

E.G.

‘ In-pile corrosion test loops for aqueous homogeneous reactor solutions’, ORNL-2977

Oak Ridge Natioanl Laboratory

Oak Ridge, TN, USA

1960.

22.

Davis

R. J.

and H:

G.H.

‘In-pile-autoclave test of Zircaloy-2 corrosion in UO2(NO3)2 solution and of solution stability, ORNL-3171

Oak Ridge national Laboratory, Oak Ridge

TN, USA

1962.

23.

Pearce

M. L.

and Griffiths

V. S.

: Corros. TechnoL 1960 7 142.

24.

Fox

J. M.

: ‘Corrosion of stainless in concentrated UNH solutions’ HDC-2214 Nucleonics Department, General Electric Hanford Works Hanford, Washington 1951.

25.

Takeda

Nagai

Koizumi

and Hayashi

: Proc. 3rd Int. Conf. on ‘Nuclear fuel prepocessing and waste management’ RECOD ‘91, Sendai, Japan 1991 Atomic Energy Society of Japan, Japan Atomic Industrial Forum 555.

26.

Takeuchi

and Whillock

G. O. H.

: J. Nucl. Sci. Technol., 2004 41 702.

27.

Bohlmann

E. G.

and M:

G.M.

‘Stress corrosion cracking problems in the homogeneous reactor test’, CF-57-1-143

Oak Ridge National Laboratory

Oak Rodge, TN, USA

1957.

28.

Baker

J. E.

Silverman

M. D.

Jenks

G. H.

and R:

A.R.

‘HRT corrosion samples — additional data on specimens removed prior to run no. 20’, CF-61-2-95

Oak Ridge National Laboratory

Oak Ridge, TN, USA

1961.

29.

King

L. D. P.

: ‘Status of the work related to the King reactor as of March 1972’

LA-4926-MS, Los Alamos National Laboratory

Los Alamos, NM, USA

1972.

30.

Ferguson

D. E.

Leuze

R. E.

and A:

R.A.

‘ Predicted behavior of fission products in the HRT’, ORNL CF-56-2-87 Oak Ridge National Laboratory

Oak Ridge, TN, USA

1956.

31.

Arroyave

and Morcillo

: Corros. Sci., 1995 37 293.

32.

Hayashi

Ojima

Kawaguchi

Shinohara

and Kawano

: J. Atom. Energ. Soc. Jpn 1989 31 89.

33.

Evans

U. R.

: Trans. Faraday Soc., 1944 40 120.

34.

Suzuki

Tsukaue

Yoshida

and Hirose

: ‘Corrosion study of stainless steels in a dissolver off-gas environment’Proc. 3rd Int. Conf. on ‘Nuclear fuel prepocessing and waste management’ RECOD ‘91

Sendai, Japan

1991 Atomic Energy Society of Japan, Japan Atomic Industrial Forum564.

35.

Tsukaue

Kudo

Makao

Yamaski

and KImura

: Corrosion 1993 49 220.

36.

Tsukaue

Nakao

Takimoto

and Yoshida

: Corrosion 1994 50 755.

37.

Sidky

P. S.

: J. Nucl. Mater., 1998 256 1.

38.

Une

: J. Nucl. Sci. Technol., 1979 16 660.

39.

Une

: J. Nucl. Sci. Technol., 1977 14 443.

40.

Wren

J. C.

and Glowa

G. A.

: Nucl. TechnoL 2001 133 33.

41.

Wren

J. C.

Glowa

G. A.

and Merrit

: J. Nucl. Mater., 1999 265 161.

42.

Poole

L. K.

: ‘The welding of type 347 steels’ NYO-3499

Oak Ridge National Laboratory

Oak Ridge, TN, USA

1955.

43.

Ebling

H. F.

and A:

M.A.

Weld. 1 1951 30, 511.

44.

Holzworth

M. L.

Beck

F. H.

and Fontana

M. G.

: Corrosion 1951 7, 441.

45.

‘Time temperature sensitization (TTS) diagrams for Types 347, 304L and 316L stainless steels’, ‘Advances in the technology of stainless steels and related alloys’ ASTM STP 369; 1963

Philadelphia

PA, American Society for Testing Materials.