ASTM E1035-18(2023)
(Practice)Standard Practice for Determining Neutron Exposures for Nuclear Reactor Vessel Support Structures
Standard Practice for Determining Neutron Exposures for Nuclear Reactor Vessel Support Structures
SIGNIFICANCE AND USE
3.1 Prediction of neutron radiation effects to pressure vessel steels has long been a part of the design and operation of light water reactor power plants. Both the federal regulatory agencies (see 2.3) and national standards groups (see 2.1 and 2.2) have promulgated regulations and standards to ensure safe operation of these vessels. The support structures for pressurized water reactor vessels may also be subject to similar neutron radiation effects (1, 3-6).2 The objective of this practice is to provide guidelines for determining the neutron radiation exposures experienced by individual vessel supports.
3.2 It is known that high-energy photons can also produce displacement damage effects that may be similar to those produced by neutrons. These effects are known to be much less at the belt line of a light water reactor pressure vessel than those induced by neutrons. The same has not been proven for all locations within vessel support structures. Therefore, it may be prudent to apply coupled neutron-photon transport methods and photon-induced displacement cross sections to determine whether gamma-induced dpa exceeds the screening level of 3.0 × 10–4 used in this practice for neutron exposures. (See 1.3.)
SCOPE
1.1 This practice covers procedures for monitoring the neutron radiation exposures experienced by ferritic materials in nuclear reactor vessel support structures located in the vicinity of the active core. This practice includes guidelines for:
1.1.1 Selecting appropriate dosimetric sensor sets and their proper installation in reactor cavities.
1.1.2 Making appropriate neutronics calculations to predict neutron radiation exposures.
1.2 The values stated in SI units are to be regarded as standard; units that are not SI can be found in Terminology E170 and are to be regarded as standard. Any values in parentheses are for information only.
1.3 This practice is applicable to all pressurized water reactors whose vessel supports will experience a lifetime neutron fluence (E > 1 MeV) that exceeds 1 × 1017 neutrons/cm2 or exceeds 3.0 × 10−4 dpa (1).2 (See Terminology E170.)
1.4 Exposure of vessel support structures by gamma radiation is not included in the scope of this practice, but see the brief discussion of this issue in 3.2.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. (For example, (2).)
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
- Status
- Published
- Publication Date
- 31-May-2023
- Technical Committee
- E10 - Nuclear Technology and Applications
- Drafting Committee
- E10.05 - Nuclear Radiation Metrology
Relations
- Effective Date
- 01-Mar-2020
- Effective Date
- 01-Mar-2020
- Effective Date
- 01-Nov-2019
- Effective Date
- 01-Oct-2019
- Effective Date
- 01-Jun-2018
- Effective Date
- 01-Feb-2018
- Effective Date
- 01-Jun-2017
- Effective Date
- 01-Oct-2016
- Effective Date
- 15-Feb-2016
- Effective Date
- 01-Sep-2015
- Effective Date
- 01-Jul-2015
- Effective Date
- 15-Mar-2015
- Effective Date
- 15-Oct-2014
- Effective Date
- 01-Sep-2014
- Effective Date
- 01-Jul-2014
Overview
ASTM E1035-18(2023), Standard Practice for Determining Neutron Exposures for Nuclear Reactor Vessel Support Structures, establishes critical guidelines for monitoring neutron radiation exposure in ferritic materials within reactor vessel support structures. Developed by ASTM International, this standard addresses the need to evaluate and predict the effects of neutron irradiation on support structures, particularly in pressurized water reactors (PWRs), to ensure long-term safety and regulatory compliance. By outlining best practices for selecting dosimetry, performing neutron transport calculations, and evaluating exposures, ASTM E1035-18(2023) supports effective maintenance and mitigation strategies in nuclear facilities.
Key Topics
- Neutron Exposure Monitoring: The standard defines procedures for monitoring neutron radiation experienced by support structures near the reactor core in nuclear power plants.
- Dosimetry Guidelines: Recommendations for selecting and installing appropriate dosimetric sensor sets within reactor cavities are provided, with references to relevant ASTM guides and test methods.
- Neutronics Calculations: Methods for predicting neutron exposure, including consideration for complex geometries and support system placements, are included. The standard references analytic techniques such as discrete ordinates and Monte Carlo calculations.
- Operational Safety and Compliance: Practical advice is given on establishing safety, health, and environmental practices, as well as guidance on meeting regulatory requirements for neutron exposure assessment.
- Thresholds and Criteria: The practice applies when neutron fluence (E > 1 MeV) exceeds 1 × 10¹⁷ neutrons/cm² or 3.0 × 10⁻⁴ dpa during the lifetime operation of vessel supports.
Applications
ASTM E1035-18(2023) is widely applicable in the nuclear energy sector, specifically for:
- Nuclear Power Plant Operators: Enables accurate assessment of neutron-induced damage in vessel support structures, facilitating maintenance planning and ensuring regulatory compliance.
- Reactor Designers and Engineers: Provides a framework for predicting neutron exposure impact during the design phase, improving the robustness and resiliency of reactor support systems.
- Radiation Safety and Compliance Officers: Supports surveillance requirements by establishing a reliable methodology for exposure quantification, aiding compliance with federal and international standards.
- Dosimetry Specialists and Researchers: Serves as a reference for selecting dosimeters, performing irradiation mapping, and conducting advanced neutron transport simulations using established ASTM methodologies.
- Regulatory Authorities: Used to verify that operators are adhering to safety criteria regarding neutron fluence and displacement per atom (dpa) values, contributing to the overall safe operation of nuclear facilities.
Related Standards
ASTM E1035-18(2023) integrates and references several other standards and regulatory documents essential for comprehensive neutron exposure determination:
- ASTM E170: Terminology Relating to Radiation Measurements and Dosimetry
- ASTM E482: Guide for Application of Neutron Transport Methods for Reactor Vessel Surveillance
- ASTM E693: Practice for Characterizing Neutron Exposures in Iron and Low Alloy Steels in Terms of Displacements Per Atom (dpa)
- ASTM E844, E854, E910, E944, E1005, E1018, E2956: Various guides and test methods for sensor design, neutron spectrum adjustment, and application of dosimetry techniques
- ASME Boiler and Pressure Vessel Code, Section III
- 10 CFR Part 50 (Appendices G and H): U.S. regulatory requirements for reactor pressure vessel materials surveillance
- Regulatory Guide 1.99: Guidance on effects of residual elements on predicted radiation damage
By following ASTM E1035-18(2023), nuclear facilities can ensure accurate monitoring, assessment, and management of neutron exposures-and thus maintain the structural integrity and safety of nuclear reactor vessel supports throughout their operational lifespan.
Keywords: neutron exposure, reactor vessel supports, neutron fluence, dpa, dosimetry, nuclear power plant, radiation monitoring, ASTM E1035-18(2023)
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Frequently Asked Questions
ASTM E1035-18(2023) is a standard published by ASTM International. Its full title is "Standard Practice for Determining Neutron Exposures for Nuclear Reactor Vessel Support Structures". This standard covers: SIGNIFICANCE AND USE 3.1 Prediction of neutron radiation effects to pressure vessel steels has long been a part of the design and operation of light water reactor power plants. Both the federal regulatory agencies (see 2.3) and national standards groups (see 2.1 and 2.2) have promulgated regulations and standards to ensure safe operation of these vessels. The support structures for pressurized water reactor vessels may also be subject to similar neutron radiation effects (1, 3-6).2 The objective of this practice is to provide guidelines for determining the neutron radiation exposures experienced by individual vessel supports. 3.2 It is known that high-energy photons can also produce displacement damage effects that may be similar to those produced by neutrons. These effects are known to be much less at the belt line of a light water reactor pressure vessel than those induced by neutrons. The same has not been proven for all locations within vessel support structures. Therefore, it may be prudent to apply coupled neutron-photon transport methods and photon-induced displacement cross sections to determine whether gamma-induced dpa exceeds the screening level of 3.0 × 10–4 used in this practice for neutron exposures. (See 1.3.) SCOPE 1.1 This practice covers procedures for monitoring the neutron radiation exposures experienced by ferritic materials in nuclear reactor vessel support structures located in the vicinity of the active core. This practice includes guidelines for: 1.1.1 Selecting appropriate dosimetric sensor sets and their proper installation in reactor cavities. 1.1.2 Making appropriate neutronics calculations to predict neutron radiation exposures. 1.2 The values stated in SI units are to be regarded as standard; units that are not SI can be found in Terminology E170 and are to be regarded as standard. Any values in parentheses are for information only. 1.3 This practice is applicable to all pressurized water reactors whose vessel supports will experience a lifetime neutron fluence (E > 1 MeV) that exceeds 1 × 1017 neutrons/cm2 or exceeds 3.0 × 10−4 dpa (1).2 (See Terminology E170.) 1.4 Exposure of vessel support structures by gamma radiation is not included in the scope of this practice, but see the brief discussion of this issue in 3.2. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. (For example, (2).) 1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
SIGNIFICANCE AND USE 3.1 Prediction of neutron radiation effects to pressure vessel steels has long been a part of the design and operation of light water reactor power plants. Both the federal regulatory agencies (see 2.3) and national standards groups (see 2.1 and 2.2) have promulgated regulations and standards to ensure safe operation of these vessels. The support structures for pressurized water reactor vessels may also be subject to similar neutron radiation effects (1, 3-6).2 The objective of this practice is to provide guidelines for determining the neutron radiation exposures experienced by individual vessel supports. 3.2 It is known that high-energy photons can also produce displacement damage effects that may be similar to those produced by neutrons. These effects are known to be much less at the belt line of a light water reactor pressure vessel than those induced by neutrons. The same has not been proven for all locations within vessel support structures. Therefore, it may be prudent to apply coupled neutron-photon transport methods and photon-induced displacement cross sections to determine whether gamma-induced dpa exceeds the screening level of 3.0 × 10–4 used in this practice for neutron exposures. (See 1.3.) SCOPE 1.1 This practice covers procedures for monitoring the neutron radiation exposures experienced by ferritic materials in nuclear reactor vessel support structures located in the vicinity of the active core. This practice includes guidelines for: 1.1.1 Selecting appropriate dosimetric sensor sets and their proper installation in reactor cavities. 1.1.2 Making appropriate neutronics calculations to predict neutron radiation exposures. 1.2 The values stated in SI units are to be regarded as standard; units that are not SI can be found in Terminology E170 and are to be regarded as standard. Any values in parentheses are for information only. 1.3 This practice is applicable to all pressurized water reactors whose vessel supports will experience a lifetime neutron fluence (E > 1 MeV) that exceeds 1 × 1017 neutrons/cm2 or exceeds 3.0 × 10−4 dpa (1).2 (See Terminology E170.) 1.4 Exposure of vessel support structures by gamma radiation is not included in the scope of this practice, but see the brief discussion of this issue in 3.2. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. (For example, (2).) 1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
ASTM E1035-18(2023) is classified under the following ICS (International Classification for Standards) categories: 27.120.20 - Nuclear power plants. Safety. The ICS classification helps identify the subject area and facilitates finding related standards.
ASTM E1035-18(2023) has the following relationships with other standards: It is inter standard links to ASTM E1018-20e1, ASTM E1018-20, ASTM E854-19, ASTM E944-19, ASTM E844-18, ASTM E910-18, ASTM E170-17, ASTM E170-16a, ASTM E170-16, ASTM E170-15a, ASTM E1005-15, ASTM E170-15, ASTM E170-14a, ASTM E170-14, ASTM E854-14. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
ASTM E1035-18(2023) is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E1035 − 18 (Reapproved 2023)
Standard Practice for
Determining Neutron Exposures for Nuclear Reactor Vessel
Support Structures
This standard is issued under the fixed designation E1035; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 This practice covers procedures for monitoring the
E170 Terminology Relating to Radiation Measurements and
neutron radiation exposures experienced by ferritic materials in
Dosimetry
nuclear reactor vessel support structures located in the vicinity
E482 Guide for Application of Neutron Transport Methods
of the active core. This practice includes guidelines for:
for Reactor Vessel Surveillance
1.1.1 Selecting appropriate dosimetric sensor sets and their
E693 Practice for Characterizing Neutron Exposures in Iron
proper installation in reactor cavities.
and Low Alloy Steels in Terms of Displacements Per
1.1.2 Making appropriate neutronics calculations to predict
Atom (DPA)
neutron radiation exposures.
E844 Guide for Sensor Set Design and Irradiation for
1.2 The values stated in SI units are to be regarded as
Reactor Surveillance
standard; units that are not SI can be found in Terminology
E854 Test Method for Application and Analysis of Solid
E170 and are to be regarded as standard. Any values in
State Track Recorder (SSTR) Monitors for Reactor Sur-
parentheses are for information only.
veillance
1.3 This practice is applicable to all pressurized water
E910 Test Method for Application and Analysis of Helium
reactors whose vessel supports will experience a lifetime Accumulation Fluence Monitors for Reactor Vessel Sur-
neutron fluence (E > 1 MeV) that exceeds 1 × 10 neutrons/
veillance
2 −4 2
cm or exceeds 3.0 × 10 dpa (1). (See Terminology E170.) E944 Guide for Application of Neutron Spectrum Adjust-
ment Methods in Reactor Surveillance
1.4 Exposure of vessel support structures by gamma radia-
E1005 Test Method for Application and Analysis of Radio-
tion is not included in the scope of this practice, but see the
metric Monitors for Reactor Vessel Surveillance
brief discussion of this issue in 3.2.
E1018 Guide for Application of ASTM Evaluated Cross
1.5 This standard does not purport to address all of the
Section Data File
safety concerns, if any, associated with its use. It is the
E2956 Guide for Monitoring the Neutron Exposure of LWR
responsibility of the user of this standard to establish appro-
Reactor Pressure Vessels
priate safety, health, and environmental practices and deter-
2.2 ASME Standard:
mine the applicability of regulatory limitations prior to use.
Boiler and Pressure Vessel Code, Section III
(For example, (2).)
2.3 Nuclear Regulatory Documents:
1.6 This international standard was developed in accor-
Code of Federal Regulations, Chapter 10, Part 50, Appendix
dance with internationally recognized principles on standard-
G Fracture Toughness Requirements
ization established in the Decision on Principles for the
Code of Federal Regulations, Chapter 10, Part 50, Appendix
Development of International Standards, Guides and Recom-
H Reactor Vessel Materials Surveillance Program Re-
mendations issued by the World Trade Organization Technical
quirements
Barriers to Trade (TBT) Committee.
Regulatory Guide 1.99, Rev. 2 Effects of Residual Elements
1 3
This practice is under the jurisdiction of ASTM Committee E10 on Nuclear For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Technology and Applications and is the direct responsibility of Subcommittee contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
E10.05 on Nuclear Radiation Metrology. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved June 1, 2023. Published June 2023. Originally the ASTM website.
approved in 1985. Last previous edition approved in 2018 as E1035 – 18. DOI: Available from American Society of Mechanical Engineers, 345 E. 47th St.,
10.1520/E1035-18R23. New York, NY 10017.
2 5
The boldface numbers in parentheses refer to a list of references at the end of Available from Superintendent of Documents, U.S. Government Printing
this practice. Office, Washington, DC 20402.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1035 − 18 (2023)
on Predicted Radiation Damage on Reactor Vessel 5. Determination of Neutron Exposure Parameter Values
Materials, U.S. Nuclear Regulatory Commission, May
5.1 Neutronics Calculations—All neutronics calculations
for (a) the analysis of integral dosimetry data, and (b) the
prediction of irradiation damage exposure parameter values
3. Significance and Use
shall follow Guide E482, subject to these additional consider-
3.1 Prediction of neutron radiation effects to pressure vessel
ations that may be encountered in reactor cavities:
steels has long been a part of the design and operation of light
5.1.1 If the vessel supports do not lie within the core’s
water reactor power plants. Both the federal regulatory agen-
active height, then an asymmetric quadrature set must be
cies (see 2.3) and national standards groups (see 2.1 and 2.2)
chosen for discrete ordinates calculations that will accurately
have promulgated regulations and standards to ensure safe
reproduce the neutron transport in the direction of the supports.
operation of these vessels. The support structures for pressur-
Care must be exercised in constructing the quadrature set to
ized water reactor vessels may also be subject to similar
ensure that “ray streaming” effects in the cavity air gap do not
neutron radiation effects (1, 3-6). The objective of this
distort the calculation of the neutron transport.
practice is to provide guidelines for determining the neutron
5.1.2 If the support system is so large or geometrically
radiation exposures experienced by individual vessel supports.
complex that it perturbs the general neutron field in the cavity,
the analysis method of choice may be that of a Monte Carlo
3.2 It is known that high-energy photons can also produce
displacement damage effects that may be similar to those calculation or a combined discrete ordinates/Monte Carlo
calculation. The combined calculation involves a two or
produced by neutrons. These effects are known to be much less
at the belt line of a light water reactor pressure vessel than three-dimensional discrete or
...
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