International Conference on Fast Reactors and Related Fuel Cycles (FR09), December 7 - 11, 2009 Kyoto, Japan

EPEP--450 Steel450 Steel as Cladding Material for Fast as Cladding Material for Fast Neutron Reactor Fuel RodsNeutron Reactor Fuel Rods

A.Povstyanko, V.Prokhorov,A. Fedoseyev , F.Kryukov

JSC “SSC – RIAR”

International Conference on Fast Reactors and Related Fuel Cycles (FR09), December 7 - 11, 2009 Kyoto, Japan

0.005-0.015

0.1-0.3

0.15-0.40

1.5-2.0

0.05-0.30

11.0-13.5≤≤≤≤ 1.0≤≤≤≤ 0.50.10-

0.15EP-450

BVNbMoNiCrMnSiCComposition, % mass.

Material

VNIINM (Bochvar Institute)R I A R

Patent № 677544 15.11.77

International Conference on Fast Reactors and Related Fuel Cycles (FR09), December 7 - 11, 2009 Kyoto, Japan

Main irradiation parameters of fuel rods with EP-450 steel claddings and pelleted oxide fuel in BOR-60 and BN-350 reactors

Test time within

temperature range, h

Temperature of cladding internal layer, 0С

Linear power, W/cm

Test time at power, h

Dose,dpa

Burnup %, h.a.

UO2 fuel pelletsFA index

Reactor

-650-537470-36097506011,233% enrichmentU235

ОP-6

-690-587536-43075004810,632,8 % enrichmentU235

ОP-5BN-350

16408500

>730730-700

450125004512,5- « -ОP-25- « -- « -- « -- « -4110,6- « -ОP-24- « -- « -- « -- « -4210,8- « -ОP-23- « -- « -- « -- « -4010,4- « -ОP-22

10905780

725-700700-655

> 490490-400

100804210,8- « -ОP-21

29709903

> 690690-630

> 464464-340

1384041,513,4- « -А-337

13988685

> 667 667-620

> 477477-400

104204912,390%enrichmentU235

А-336BOR-60

International Conference on Fast Reactors and Related Fuel Cycles (FR09), December 7 - 11, 2009 Kyoto, Japan

-- tight fuel rods;tight fuel rods;

- damage fuel rods .- leaky fuel rods;

Chart of the OP-25 FA

International Conference on Fast Reactors and Related Fuel Cycles (FR09), December 7 - 11, 2009 Kyoto, Japan

Typical diametral strain in OP-25 fuel rod

International Conference on Fast Reactors and Related Fuel Cycles (FR09), December 7 - 11, 2009 Kyoto, Japan

Typical areas of local thinning damage areas and several non-through ruptures of the cladding in the upper part of the fuel rods

Damage fuel rods

International Conference on Fast Reactors and Related Fuel Cycles (FR09), December 7 - 11, 2009 Kyoto, Japan

Maximum diametral strain in OP-25 fuel rods (BOR-60 reactor) vs. maximum initial irradiation temperature (--- level of maximum allowable form change)

International Conference on Fast Reactors and Related Fuel Cycles (FR09), December 7 - 11, 2009 Kyoto, Japan

Structure of cross section fragments of OP-21 fuel rods after irradiation:

a) cladding matrix corrosion;b) cladding pitting

Corrosion

a b

International Conference on Fast Reactors and Related Fuel Cycles (FR09), December 7 - 11, 2009 Kyoto, Japan

0 40 80

120 160 200

510 560 610 660 710 Temperature, °С

Corro

sion d

epth,

mkm

Corrosion

Temperature dependence of corrosion depth in EP-450 steel claddings at a burn-up of 10.8 % h.a.

International Conference on Fast Reactors and Related Fuel Cycles (FR09), December 7 - 11, 2009 Kyoto, Japan

Decarburization of EP-450- steel claddings from the coolant side

Decarburization

International Conference on Fast Reactors and Related Fuel Cycles (FR09), December 7 - 11, 2009 Kyoto, Japan

Storage in cooling pool BOR-60

International Conference on Fast Reactors and Related Fuel Cycles (FR09), December 7 - 11, 2009 Kyoto, Japan

Storage in cooling pool BN-350

International Conference on Fast Reactors and Related Fuel Cycles (FR09), December 7 - 11, 2009 Kyoto, Japan

600 - 470352∼16330.0UO2VS-007

650 - 510478∼14227.8(0.8U+0.2Pu)O2ОG-117

650 - 530476∼13224.4(0.8U+0.2Pu)O2ОG-116

690 - 540485∼10821.0(0.8U+0.2Pu)O2ОG-115

Maximum and minimum

temperature of cladding internal

layer, 0С

Maximum linear power, W/cm

Maximum damage dose,

dpa

Burnup%, h.a.

FuelFA index

Irradiation parameters of fuel rods with EP-450 steel claddings and

vibropacked fuel

International Conference on Fast Reactors and Related Fuel Cycles (FR09), December 7 - 11, 2009 Kyoto, Japan

0,0

1,0

2,0

3,0

4,0

100 110 120 130 140 150 160 170Damage dose, dpa

Strain

, %Swelling x1/3Diameter change

Maximum diametral strain of EP-450 steel claddings

International Conference on Fast Reactors and Related Fuel Cycles (FR09), December 7 - 11, 2009 Kyoto, Japan

a b c

Structure of EP-450 steel as cladding material for BS-007 fuel rods irradiated in BOR-60 reactor (a – general view, х20000; b –voids,

dislocation network and χ -phase precipitates in ferrite, х40000; c – voidsand secondary phase precipitates in sorbite, х40000

Structure of EP-450 steel

International Conference on Fast Reactors and Related Fuel Cycles (FR09), December 7 - 11, 2009 Kyoto, Japan

�The EP-450 steel as a cladding material for fast reactor fuel rods retains its high resistance to radiation swelling at damagedoses of up to 160 dpa.

�The main factors hindering reliable performance of the fuel rods with EP-450 claddings are the maximum initial temperature and the level of stresses in the claddings caused by gas and fuel pressure.

�The problems associated with heat strength and corrosion by the iodine transport reaction can be resolved by decreasing the maximum initial temperature down to 650°C. �Use of the EP-450 steel as a cladding material in the BN commercial reactors is impossible with the FA storage technology available now.

Conclusions