ISO 7097-2-2022 PDF

Full title and description

ISO 7097-2:2022 — Nuclear fuel technology — Determination of uranium in solutions, uranium hexafluoride and solids — Part 2: Iron(II) reduction/cerium(IV) oxidation titrimetric method. This international standard specifies a titrimetric analytical procedure using Fe(II) reduction and Ce(IV) oxidation for accurately determining uranium in a range of nuclear fuel materials and product solutions.

Abstract

This document describes an analytical titrimetric method suitable for determination of uranium in samples such as uranium metal, UO2, UO3, U3O8, uranyl nitrate hexahydrate and uranium hexafluoride. The procedure is intended to provide sufficient accuracy and precision for nuclear materials accountability; it tolerates fission-product levels equivalent to about 10% burn-up and recommends mass titration and, where appropriate, the use of automatic devices. The method produces no toxic mixed waste as does the potassium dichromate titration described in earlier versions.

General information

• Status: Published.
• Publication date: 25 November 2022 (Second edition, 2022-11).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 27.120.30 (Nuclear fuel technology).
• Edition / version: 2nd edition (2022).
• Number of pages: 17 pages.

Scope

Specifies a titrimetric method based on iron(II) reduction followed by cerium(IV) oxidation for determining uranium in solutions, UF6 and a variety of solid uranium-containing materials from the nuclear fuel cycle. The procedure is applicable to uranium metal, uranium oxides and uranyl nitrate product solutions, and is suitable for routine analyses where accuracy and precision are required for materials accountancy. The method is designed to tolerate typical fission product concentrations (up to about 10% heavy-atom burn-up) and recommends mass titration to improve precision; it also notes that alternative techniques providing equivalent performance may be used.

Key topics and requirements

• Analytical principle: reduction of U(VI) to U(IV) by Fe(II) followed by oxidation with Ce(IV) as titrant; end‑point detection and calculation of uranium content.
• Scope of materials: uranium metal, UO2, UO3, U3O8, uranyl nitrate hexahydrate, uranium hexafluoride and similar nuclear fuel products.
• Reagents and apparatus: specification of required reagents (including preparation and purity), titrants, and volumetric/titration apparatus; provisions for automated devices.
• Sample preparation: procedures for dissolution, conversion (where necessary), and aliquot handling for solids, powders, pellets and gaseous/condensed UF6.
• Interferences and reactions: description of expected side reactions, common interferences (and their limits), and handling of samples with fission-product levels up to ~10% burn-up.
• Accuracy, precision and mass-titration recommendation: use of mass titration to improve measurement precision and suitability for safeguards/accountability.
• Safety and waste considerations: method avoids generating toxic mixed waste associated with potassium dichromate titrations used in earlier methods.

Typical use and users

Used by analytical laboratories in the nuclear fuel cycle: process control and quality laboratories at uranium conversion and fuel fabrication plants, reprocessing facilities, safeguards and regulatory laboratories, and research laboratories requiring reliable quantitative uranium assays for materials accountancy and quality assurance. Analytical chemists, laboratory managers and nuclear safeguards professionals are typical users.

Related standards

This part is one of the ISO 7097 series of methods for uranium determination. It follows and replaces earlier titrimetric approaches (including methods in ISO 7097:1983 and the earlier ISO 7097-2:2004) and is complementary to other analytical standards and national methods used for uranium assay and nuclear materials analysis. Relevant related entries include ISO 7097-1 and previous ISO 7097 editions.

Keywords

uranium determination; titrimetry; iron(II) reduction; cerium(IV) oxidation; nuclear fuel technology; uranium hexafluoride; uranyl nitrate; mass titration; analytical chemistry; safeguards.

FAQ

Q: What is this standard?

A: ISO 7097-2:2022 is the second-edition international standard that specifies an iron(II) reduction / cerium(IV) oxidation titrimetric method for determination of uranium in solutions, UF6 and solid uranium materials used in the nuclear fuel cycle.

Q: What does it cover?

A: It covers the analytical principle, reagents, apparatus, sample-preparation procedures, reactions and interferences, and calculation/reporting conventions for accurate uranium assay. It is intended for use where accuracy and precision are required for materials accountancy and quality control.

Q: Who typically uses it?

A: Analytical laboratories in conversion, fuel fabrication, reprocessing and regulatory/safeguards organizations; analytical chemists and laboratory personnel performing quantitative uranium assays.

Q: Is it current or superseded?

A: Current — published 25 November 2022 as the second edition. It supersedes earlier versions in the ISO 7097 series (previously covered by ISO 7097-2:2004 and the older ISO 7097 family).

Q: Is it part of a series?

A: Yes — it is Part 2 of the ISO 7097 series dealing with uranium determination; other parts and earlier editions address alternative titrimetric procedures and related analytical methods for uranium.

Q: What are the key keywords?

A: Uranium determination; titrimetric method; iron(II); cerium(IV); nuclear fuel; UF6; uranyl nitrate; mass titration; materials accountancy.