invescgacng(uranium,(neptunium(and( … 10aug2019.pdf · takechome(messages!...

Michael(E.(Ke,erer,(Professor(Emeritus,(Chemistry(and(Biochemistry(

Sco,(C.(Szechenyi,(Research(Affiliate,(School(of(Environmental(Sustainability(

InvesCgaCng(uranium,(neptunium(and(plutonium(contaminaCon(in(environmental(samples(from(the(Piketon,(Ohio(vicinity(

August(10,(2019(

What(is(our(work(in(isotope(signatures?!

((((Answer(quesCons(of(origin:((does(“this”(comes(from(“there”?(

(e.g.((Does(uranium(come(from(Nature,(or(from(the(PORTS(facility?(Or(a(mixture(thereof?(

(We(are(also(concerned(with(quesCons(of(“how(much”,(but(that(is(a(separate(quesCon(

(“From(where”(is(the(first(objecCve((

(We(use(atom(counCng(instruments(known(as(mass(spectrometers(to(measure(isotope(raCos(

2!

What(is(an(isotope?(An(isotope(is(a(specific(combinaCon(of(protons(and(

neutrons(in(the(atomic(nucleus.(((

Isotopes(of(the(same(element(have(the(same(number(of(protons(but(different(numbers(of(neutrons.(

Some(isotopes(are(stable(indefinitely,(and(others(spontaneously(change(into(another(

isotope.((This(transformaCon(is(referred(to(as(radioacCve(decay.(

PenetraCng(power(of(radioacCvity(

•  Alpha(parCcles:((heavy,(easily(stopped;(most(damaging(when(taken(internally(

•  Beta(parCcles:((intermediate(penetraCon(

•  Gamma(parCcles:((highly(penetraCng(

Photo credits: http://energy.cr.usgs.gov/radon/georadon/usaeu.gif

1979(Church(Rock(Tailings(Dam(Failure(

On(July(16,(1979,(a(uranium(mill(tailings(dam(failed(at(Church(Rock,(

New(Mexico,(due(to(se,lement(of(the(base(of(the(dam.((370,000(m3(of(contaminated(water(and(106(kg(of(sludge(were(carried(up(to(110(km(downstream(in(the(Puerco(River,(deposiCng(contaminated(sediment(and(infiltraCng(the(alluvial(aquifer.(

h'p://www.city1data.com/city/Church1Rock1New1Mexico.html!

Sample ((( (((((((240Pu/239Pu(

CAc3((( ( (((((((( (0.084(±(0.001(

CAc4 (( ( ( (0.083(±(0.001(

Isotope(fingerprinCng(Isotope( (atom)( raCos( provide( disCnctly(different( informaCon( than( concentraCons:(where%from%vs.%how%much%

Enriched(U,(depleted(U,(recycled(U(?(

Are( Np( and( Pu( from( “fallout”( or( another(source?(

15!

Isotope(fingerprinCng(238U,( 235U,( 234U,( 236U( are( four(isotopes( measurable( by( mass(spectrometry;( 233U( and( 232U( are(syntheCc(

234U/238U,(235U/238U,(236U/238U(16!

18!

Recycled%uranium%introduces%236U,%

Np,%Pu,%Tc%%

InvesCgaCng(mixtures(with(“mixing(plots”(

• Measure(two(different(raCos(with(a(common(denominator((e.g.,(C/A(and(B/A)(• Make(a(plot(of(C/A(vs.(B/A(

•  Look(for(“endcmembers”,(linear(mixing(pa,ern(of(two(sources,(or(mulCccomponent(mixing(

19!

Mixing(line(

0.00000

0.00002

0.00004

0.00006

0.00008

0.00010

0.0020 0.0040 0.0060 0.0080

235U/238U

234U/238U

DU!

Natural U!

Secular equilibrium!

21!

A(mass(spectrum(

Mass(

#(atoms(

239Pu(

240Pu(

23!

InducCvely( coupled( plasma( mass(spectrometry( (ICPMS)( is( the( single( most(important(technique(for(elemental(analysis(at( ultractrace( to( major( levels,( and( for(isotopic(analysis(of(the(“heavier”(elements!

From(A(to(Z:(((6Li(to(244Pu!

Cu2+!(aq)!

xCu+!(g)!

The analyte

The analyte, after preparative separation

and pre-concentration

Former(Apollo(site(vicinity(samples((

Nature!

All#samples#collected#in#the#blue#area#exhibited#detectable#enriched#U#

Naturally!occurring!U!found!

Naturally!occurring!U!found!

Takechome(messages!((((Isotope(raCos(are(a(truth(serum(for(idenCfying(contaminants(–(

that(the(PORTS(Facility(is(a(source(of(U,(Np,(and(Pu(in(the(offsite(environment(–(is(indisputable(

((((We(have(not,(and(do(not,(assess(radiological(hazards.((We(follow(trails(of(breadcrumbs,(and(focus(on(“does(this(come(from(there”((

(((((PORTScrelated(contaminaCon(can(be(expected(to(be(present(in(the(ambient(environment,(offsite,(near(the(facility((

(Perpetual(environmental(monitoring,(of(a(communitycbased(nature,(is(urgently(needed(

82!

invescgacng(uranium,(neptunium(and( … 10aug2019.pdf · takechome(messages!...

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