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LUND UNIVERSITY LIBRARIES

DEVELOPMENT OF RISK INFORMED METHODS FOR ESTIMATING RADIATION RELEASE FROM CABLE FIRES AT HIGH ENERGY PHYSICS FACILITIES

Funk, Daniel LU (2020) In LUTVDG/TVBB VBRM05 20201
Division of Fire Safety Engineering
Abstract
CERN operates the Large Hadron Collider (LHC), the world’s largest and most powerful particle accelerator. The LHC was built to advance the state of knowledge in particle physics by increasing the energy of colliding particles to the TeV range. With this increase in capability comes increased fire safety challenges, including the need for more accurate assessment of fire-induced release of radioactive materials. Through normal operation of particle accelerators, some materials used in the facility structure and equipment are made radioactive through a process called proton activation. Electrical cables are susceptible to proton activation; therefore, a cable fire can potentially result in liberation of radionuclides to the environment.... (More)
CERN operates the Large Hadron Collider (LHC), the world’s largest and most powerful particle accelerator. The LHC was built to advance the state of knowledge in particle physics by increasing the energy of colliding particles to the TeV range. With this increase in capability comes increased fire safety challenges, including the need for more accurate assessment of fire-induced release of radioactive materials. Through normal operation of particle accelerators, some materials used in the facility structure and equipment are made radioactive through a process called proton activation. Electrical cables are susceptible to proton activation; therefore, a cable fire can potentially result in liberation of radionuclides to the environment. This thesis elevates the state of knowledge and refines methods for estimating fire-induced radiation release from burning cables through (1) development of a more accurate framework for modelling cable fire sequences and quantitatively estimating cable fire frequencies and (2) development of quantitative methods for estimating the portion of radioactive isotopes released into the smoke plume of fires involving activated electrical cables.

Improved modelling of cable fire sequences was accomplished by applying electrical engineering principles to categorise and refine cable fire sequences within a fault tree format. Ignition source frequency weighting factors are then applied to associated sequences in the fault tree to produce greater precision in the determination of cable fire risk with respect to configuration, location, operating mode, and prevailing conditions. Proof-of-concept case studies confirm that the methodology is viable for “real-world” applications and can substantially improve cost-benefit analysis for risk mitigation strategies.

Conservation of mass principles were used to quantitatively analyse fractional release of radionuclides from burning cables. Mass balance inventory of pre-fire and post-fire radionuclides allowed assessment of activity levels contained in residual char, soot, and gaseous combustion products. Proof-of-concept case studies demonstrate that fractional release calculations are viable but several key influence parameters require further study to ensure accurate application. (Less)
Popular Abstract
DEVELOPMENT OF RISK INFORMED METHODS FOR ESTIMATING RADIATION RELEASE FROM CABLE FIRES AT HIGH ENERGY PHYSICS FACILITIES

CERN operates the Large Hadron Collider (LHC), the world’s largest and most powerful particle accelerator. The LHC was built to advance the state of knowledge in particle physics by increasing the energy of colliding particles to the TeV range. With this increase in capability comes increased fire safety challenges, including the need for more accurate assessment of fire-induced release of radioactive materials.

Through normal operation of particle accelerators, some materials used in the facility structure and equipment are made radioactive through a process called proton activation. Combustion is strictly a... (More)
DEVELOPMENT OF RISK INFORMED METHODS FOR ESTIMATING RADIATION RELEASE FROM CABLE FIRES AT HIGH ENERGY PHYSICS FACILITIES

CERN operates the Large Hadron Collider (LHC), the world’s largest and most powerful particle accelerator. The LHC was built to advance the state of knowledge in particle physics by increasing the energy of colliding particles to the TeV range. With this increase in capability comes increased fire safety challenges, including the need for more accurate assessment of fire-induced release of radioactive materials.

Through normal operation of particle accelerators, some materials used in the facility structure and equipment are made radioactive through a process called proton activation. Combustion is strictly a chemical process, which is blind to the radioactive process. Therefore, the radioactive materials burn no differently than non-radioactive materials. Electrical cables are susceptible to proton activation; therefore, a cable fire can generate smoke containing radioactive particles, which in turn can be released to the environment. The LHC contains a significant amount of cable to support its high energy demand and extensive control, monitoring, instrumentation, and data capture systems. Consequently, cable fires are of significant interest to CERN.

In 2018, CERN initiated a comprehensive project to develop advanced analytical tools for conducting quantitative fire risk analysis; fire-induced radioactive release is an integral part of the project. The project is called “Fire-Induced Radiological Integrated Assessment (FIRIA). The ultimate goal of the FIRIA Project is to establish reliable, accurate, and maintainable fire risk analyses for the LHC and other important CERN facilities. In support of the FIRIA Project, Lund University sponsored a thesis research effort to investigate fire-induced radiation release from cable fires. This research led to advances in technical capabilities for estimating radiological release from burning cables through (1) development of a more accurate framework for modelling cable fire sequences and quantitatively estimating cable fire frequencies and (2) development of quantitative methods for estimating the portion of radioactive isotopes released into the smoke plume of fires involving activated electrical cables.

Improved modelling of cable fire sequences was accomplished by applying electrical engineering principles to categorise and refine cable fire sequences within a fault tree format. Ignition source frequency weighting factors are then applied to associated sequences in the fault tree to produce greater precision in the determination of cable fire risk with respect to configuration, location, operating mode, and prevailing conditions. Proof-of-concept case studies confirm the methodology is viable for “real-world” applications and can substantially improve cost-benefit analysis for risk mitigation strategies.

Conservation of mass principles were used to quantitatively analyse fractional release of radiation from burning cables. Mass balance inventory of pre-fire and post-fire radionuclides allows assessment of radioactivity levels contained in residual char, soot, and gaseous combustion products. Through rigorous accounting of the radioactivity in each of the combustion products, the fraction of radioactivity that could potentially be release to the environment can be computed. Proof-of-concept case studies demonstrate that fractional release calculations are readily achievable and provide a means to quantify fire-induced radiation release to the environment from postulated cable fire scenarios.

Although the new analytical methods are viable, further research is required to refine and characterise input variables and influence parameters prior to full implementation. (Less)
Please use this url to cite or link to this publication:
author
Funk, Daniel LU
supervisor
organization
course
VBRM05 20201
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Fire Safety Engineering, CERN, Fire-induced Radiological release, particle accelerator, Fire Protection, Fire Risk Analysis
publication/series
LUTVDG/TVBB
report number
5611
other publication id
LUTVDG/TVBB-5611-SE
language
English
id
9015337
date added to LUP
2020-06-10 13:28:11
date last changed
2020-06-10 13:28:11
@misc{9015337,
  abstract     = {{CERN operates the Large Hadron Collider (LHC), the world’s largest and most powerful particle accelerator. The LHC was built to advance the state of knowledge in particle physics by increasing the energy of colliding particles to the TeV range. With this increase in capability comes increased fire safety challenges, including the need for more accurate assessment of fire-induced release of radioactive materials. Through normal operation of particle accelerators, some materials used in the facility structure and equipment are made radioactive through a process called proton activation. Electrical cables are susceptible to proton activation; therefore, a cable fire can potentially result in liberation of radionuclides to the environment. This thesis elevates the state of knowledge and refines methods for estimating fire-induced radiation release from burning cables through (1) development of a more accurate framework for modelling cable fire sequences and quantitatively estimating cable fire frequencies and (2) development of quantitative methods for estimating the portion of radioactive isotopes released into the smoke plume of fires involving activated electrical cables.

Improved modelling of cable fire sequences was accomplished by applying electrical engineering principles to categorise and refine cable fire sequences within a fault tree format. Ignition source frequency weighting factors are then applied to associated sequences in the fault tree to produce greater precision in the determination of cable fire risk with respect to configuration, location, operating mode, and prevailing conditions. Proof-of-concept case studies confirm that the methodology is viable for “real-world” applications and can substantially improve cost-benefit analysis for risk mitigation strategies.

Conservation of mass principles were used to quantitatively analyse fractional release of radionuclides from burning cables. Mass balance inventory of pre-fire and post-fire radionuclides allowed assessment of activity levels contained in residual char, soot, and gaseous combustion products. Proof-of-concept case studies demonstrate that fractional release calculations are viable but several key influence parameters require further study to ensure accurate application.}},
  author       = {{Funk, Daniel}},
  language     = {{eng}},
  note         = {{Student Paper}},
  series       = {{LUTVDG/TVBB}},
  title        = {{DEVELOPMENT OF RISK INFORMED METHODS FOR ESTIMATING RADIATION RELEASE FROM CABLE FIRES AT HIGH ENERGY PHYSICS FACILITIES}},
  year         = {{2020}},
}