Development of Hydride Neutron Absorber″ydrlde neυ fron absο rbers力 ave beer7 ρrο ροsedよ ο beυSed ′/7 Fasr Breeder ReacrOr DemOnsfrallor7 οr ρe〃 errrad′ alloη beわ aソ ′οrrabrlcar′ οηゎa1/e been strccessfυ 〃/dο ηe ノOrゎydrlde marerlals ″ere rested 1/7 1/7e Fasr eχ ρerrmenfa′

Oy0reacrο ち 」

A meta卜 hydnde has very high hydrogen atom density,whichis equivalent to that of‖ quid water Fast neutrons in nuclear
reactors are efficiently rnoderated and are absorbed in the rnetal―

hydride The Hf hydride and Zr―

Hf hydrlde disk

Gd hydrlde are considered as

Fig 2 X― ray CT image ofirradiated capsuleneutron absorberin FBR(Fast Breeder Reactor)

The development program of hydride neutron absorber
was started in」 un 2006 1t vvas accepted as an innovative

nuclear research and development pro9ram of卜Лinistry of

Education,Culture,Sports,Science and Technology of」

1400

apan

characteristics and to evaluate cost reduction effect One of
the malorR&D lems ofthe presentthe program is developmentof hydride pe‖ et,which is used in the reactor corelll Figure lshovvs the Hf hydride pe‖ et and Zr― Gd hydride pe‖ et The
slight barre― shaped transforrnations were observed, since

the pe‖ ets vvere expanded by hydrogen absorption The︑一一＞一のコ﹂﹂一一 一 Ｅ﹂０ ト

1n this study the core design is performed to examine its°

1200

︵ｏｏめヽ﹃Ｅ ∞︲０一× ︶ む

丁he program vvas accomplished in March 2009

1000'800
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600

600

700

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200000
200

300

400

500

800

900

Temperature T(K)lrradiation test of hydride neutron absorber vvas conductedOYO,atJapan Atomic EnergyAssocialon(」 AEA),where Hf hydnde disks and Z「 Gd hyd面 de.

400

transformations can be removed by grinding their sides[2,3]in the fast experimentalreactor,」.

F19 3 comparison of thermal diffusivity data ofirradiated Hfhydride disk with un― irradiated one

disks were lrradiated wth neutЮ n luence of 2 92× 1021(n/Cm2)(E>01MeV)and 3 25× 1021(n/Cm2)(E>01Me∨ )for Hf hydnde

diffusivity of Hf hydride tthis is the first experimental result ofones and Z「 Gd hydride disks respectively lrradiationthermal diffusivity ofirradiated Hf hydride ln the case of oxlde

temperatures are 590° C and 580° C for Hf hydride disks and(eg U02),1lS Well known thatthe thermal diffusivly decreases

Z「 Gd hydride disks,respectively Aler irradiation,the capsulewith the increase of the accumulated neutron irradiation dosecontaining of the hydrde disks vvas tested by X‐ ray C丁inspection method(Fig 2)丁 he result shovv that the capsulebecause of radiation dama9e tthe present results of thermal
diffusivity of irradiated Hf hydride are notevvorthy

was irradiated vvith keeping it's integrity tthe chipping and theReferences

cracking ofthe disks vvere notfound in the hydrides
After the non― destructive examinations,the capsule waslll T IWasak and K Konashi Development of Hydnde
ydr de to

cutfor sampling ofthe irradiated hydride disks for destructive

Absorbe1 lor Fast Reactor^App catlon of haln tlnll￢

examinationsi measurement of weight, meta‖ ographic test,

colntrol rod of largo fast roactor‑ lo be pul)ished in」

X― raySc Technol

diffraction test,measurement ofthermal diffusivity Nosvve‖ ing vvas found ln the disks Fi9ure 3 shows the results of

121 K Konashi et al

therrnaldiffusivitytest Thermaldiffusivitydataofun‐lti z l]9 Hydride Neutron Absorber
しirradiatedNucl

Study on an innovatve Fast Reactor
Proc of lnterlnat onalsample(blue diamond symbols)are alSO plotted in Fig 3 forCongross on Advancesin Nヒ Iclear Power Plants(ICAPP2008)

companson w‖ h irradiated data(red rectangular symbols)」tlne 8 12 2008 Anaheim、 USA

Figure 3 sholA7S that no effect of neutron irradiation on thermal[31YKtalno

etal

Fabttcalon

andmechanicalcharacterzat on of z rconiuinn and gado nium hydrdos
Ntlcl lN/ater 389(2009)170‑172」

Key Words
Hydl de Nuc ear Mater al lrradiat on Test

Contact toHf hydride pe‖ et

Zr― Gdhyd面 de pe‖ etKenil Konashi(internat onal Research Center for Nuclear
Matenals science)e―mal:konashi@imrtohoku ac ipFig 」Hydride neutron absorber pe‖ ets

KI卜 OKE卜O

Reseolch H19bl19hls 2009=錢

3/