The role of oxidizing radicals in neptunium speciation in γ-irradiated nitric acid

Bruce J. Mincher; Martin Precek; Stephen P. Mezyk; Leigh R. Martin; Alena Paulenova

doi:10.1007/s10967-012-1937-1

The role of oxidizing radicals in neptunium speciation in γ-irradiated nitric acid

Bruce J. Mincher, Martin Precek, Stephen P. Mezyk, Leigh R. Martin, Alena Paulenova

Research output: Contribution to journal › Article › peer-review

8 Scopus citations

Abstract

The irradiation of aqueous nitric acid solutions generates transient, reactive species that are known to oxidize neptunium. However, nitrous acid is also a long-lived product of nitric acid irradiation, which reduces neptunium. When we irradiated nitric acid solutions of neptunium and measured its speciation by UV/Vis spectroscopy, we found that at short irradiation times, oxidation of Np(V) to Np(VI) occurred due to reactions with radicals such as ^•OH, ^•NO₃ and ^•NO₂. However, at higher absorbed doses and after a sufficient amount of nitrous acid was produced, reduction of Np(VI) to Np(V) began to occur, eventually reaching an equilibrium distribution of these species depending on nitric acid concentration. Neptunium(IV) was not produced.

Original language	English
Pages (from-to)	27-30
Number of pages	4
Journal	Journal of Radioanalytical and Nuclear Chemistry
Volume	296
Issue number	1
DOIs	https://doi.org/10.1007/s10967-012-1937-1
State	Published - Apr 2013
Externally published	Yes

Funding

Acknowledgments Work supported through the INL Laboratory Directed Research and Development (LDRD) program, under DOE Idaho Operations Office Contract DE-AC07-05ID14517.

Funders	Funder number
U.S. Department of Energy	DE-AC07-05ID14517
Laboratory Directed Research and Development

Keywords

Free radicals
Neptunium
Nitrous acid
Radiation chemistry
Redox chemistry

Access to Document

10.1007/s10967-012-1937-1

Cite this

@article{24d2274da142486bb8a367375489bd82,

title = "The role of oxidizing radicals in neptunium speciation in γ-irradiated nitric acid",

abstract = "The irradiation of aqueous nitric acid solutions generates transient, reactive species that are known to oxidize neptunium. However, nitrous acid is also a long-lived product of nitric acid irradiation, which reduces neptunium. When we irradiated nitric acid solutions of neptunium and measured its speciation by UV/Vis spectroscopy, we found that at short irradiation times, oxidation of Np(V) to Np(VI) occurred due to reactions with radicals such as •OH, •NO3 and •NO2. However, at higher absorbed doses and after a sufficient amount of nitrous acid was produced, reduction of Np(VI) to Np(V) began to occur, eventually reaching an equilibrium distribution of these species depending on nitric acid concentration. Neptunium(IV) was not produced.",

keywords = "Free radicals, Neptunium, Nitrous acid, Radiation chemistry, Redox chemistry",

author = "Mincher, {Bruce J.} and Martin Precek and Mezyk, {Stephen P.} and Martin, {Leigh R.} and Alena Paulenova",

year = "2013",

month = apr,

doi = "10.1007/s10967-012-1937-1",

language = "English",

volume = "296",

pages = "27--30",

journal = "Journal of Radioanalytical and Nuclear Chemistry",

issn = "0236-5731",

publisher = "Akad{\'e}miai Kiad{\'o}",

number = "1",

}

TY - JOUR

T1 - The role of oxidizing radicals in neptunium speciation in γ-irradiated nitric acid

AU - Mincher, Bruce J.

AU - Precek, Martin

AU - Mezyk, Stephen P.

AU - Martin, Leigh R.

AU - Paulenova, Alena

PY - 2013/4

Y1 - 2013/4

N2 - The irradiation of aqueous nitric acid solutions generates transient, reactive species that are known to oxidize neptunium. However, nitrous acid is also a long-lived product of nitric acid irradiation, which reduces neptunium. When we irradiated nitric acid solutions of neptunium and measured its speciation by UV/Vis spectroscopy, we found that at short irradiation times, oxidation of Np(V) to Np(VI) occurred due to reactions with radicals such as •OH, •NO3 and •NO2. However, at higher absorbed doses and after a sufficient amount of nitrous acid was produced, reduction of Np(VI) to Np(V) began to occur, eventually reaching an equilibrium distribution of these species depending on nitric acid concentration. Neptunium(IV) was not produced.

AB - The irradiation of aqueous nitric acid solutions generates transient, reactive species that are known to oxidize neptunium. However, nitrous acid is also a long-lived product of nitric acid irradiation, which reduces neptunium. When we irradiated nitric acid solutions of neptunium and measured its speciation by UV/Vis spectroscopy, we found that at short irradiation times, oxidation of Np(V) to Np(VI) occurred due to reactions with radicals such as •OH, •NO3 and •NO2. However, at higher absorbed doses and after a sufficient amount of nitrous acid was produced, reduction of Np(VI) to Np(V) began to occur, eventually reaching an equilibrium distribution of these species depending on nitric acid concentration. Neptunium(IV) was not produced.

KW - Free radicals

KW - Neptunium

KW - Nitrous acid

KW - Radiation chemistry

KW - Redox chemistry

UR - http://www.scopus.com/inward/record.url?scp=84875447774&partnerID=8YFLogxK

U2 - 10.1007/s10967-012-1937-1

DO - 10.1007/s10967-012-1937-1

M3 - Article

AN - SCOPUS:84875447774

SN - 0236-5731

VL - 296

SP - 27

EP - 30

JO - Journal of Radioanalytical and Nuclear Chemistry

JF - Journal of Radioanalytical and Nuclear Chemistry

IS - 1

ER -

The role of oxidizing radicals in neptunium speciation in γ-irradiated nitric acid

Abstract

Funding

Keywords

Access to Document

Other files and links

Fingerprint

Cite this