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Title: Radiation shielding for TFTR DT diagnostics

Abstract

The authors illustrate the designs of radiation shielding for the TFTR DT diagnostics using the ACX and TVTS systems as specific examples. The main emphasis here is on the radiation transport analyses carried out in support of the designs. Initial results from the DT operation indicate that the diagnostics have been functioning as anticipated and the shielding designs are satisfactory. The experience accumulated in the shielding design for the TFTR DT diagnostics should be useful and applicable to future devices, such as TPX and ITER, where many similar diagnostic systems are expected to be used.

Authors:
; ;
Publication Date:
Research Org.:
Princeton Univ., NJ (United States). Plasma Physics Lab.
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
10164012
Report Number(s):
PPPL-CFP-3083; CONF-940630-20
ON: DE94014859; TRN: 94:013710
DOE Contract Number:
AC02-76CH03073
Resource Type:
Conference
Resource Relation:
Conference: 11. topical meeting on the technology of fusion energy,New Orleans, LA (United States),19-24 Jun 1994; Other Information: PBD: [1994]
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; TFTR TOKAMAK; PLASMA DIAGNOSTICS; MEASURING INSTRUMENTS; SHIELDS; DESIGN; RESPONSE FUNCTIONS; THICKNESS; PHYSICAL RADIATION EFFECTS; NEUTRON FLUX; 700320; PLASMA DIAGNOSTIC TECHNIQUES AND INSTRUMENTATION

Citation Formats

Ku, L.P., Johnson, D.W., and Liew, S.L.. Radiation shielding for TFTR DT diagnostics. United States: N. p., 1994. Web.
Ku, L.P., Johnson, D.W., & Liew, S.L.. Radiation shielding for TFTR DT diagnostics. United States.
Ku, L.P., Johnson, D.W., and Liew, S.L.. 1994. "Radiation shielding for TFTR DT diagnostics". United States. doi:. https://www.osti.gov/servlets/purl/10164012.
@article{osti_10164012,
title = {Radiation shielding for TFTR DT diagnostics},
author = {Ku, L.P. and Johnson, D.W. and Liew, S.L.},
abstractNote = {The authors illustrate the designs of radiation shielding for the TFTR DT diagnostics using the ACX and TVTS systems as specific examples. The main emphasis here is on the radiation transport analyses carried out in support of the designs. Initial results from the DT operation indicate that the diagnostics have been functioning as anticipated and the shielding designs are satisfactory. The experience accumulated in the shielding design for the TFTR DT diagnostics should be useful and applicable to future devices, such as TPX and ITER, where many similar diagnostic systems are expected to be used.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1994,
month = 7
}

Conference:
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  • The authors illustrate the designs of radiation shielding for the TFTR DT diagnostics using the ACX and TVTS systems as specific examples. The main emphasis here is on the radiation transport analyses carried out in support of the designs. Initial results from the DT operation indicate that the diagnostics have been functioning as anticipated and the shielding designs are satisfactory. The experience accumulated in the shielding design for the TFTR DT diagnostics should be useful and applicable to future devices, such as TPX and ITER, where many similar diagnostic systems are expected to be used.
  • High power D-T fusion reactor designs presently exhibit complex geometric and material density configurations. Simulations of the radiation shielding required for safe operation and full compliance with all regulatory requirements must include sufficient margin to accommodate uncertainties in material properties and distributions, uncertainties in the final configurations, and uncertainties in approximations employing the homogenization of complex geometries. Measurements of radiation shielding efficiency performed in a realistic D-T tokamak environment can provide empirical guidance for simulating safe, efficient, and cost effective shielding systems for future high power fusion reactors. In this work, the authors present the results of initial measurements ofmore » the TFTR radiation shielding efficiency during high power D-T operations with record neutron yields. The TFTR design objective is to limit the total dose-equivalent at the nearest PPPL property lines from all radiation pathways to 10 mrem per calendar year. Compliance with this design objective over a calendar year requires measurements in the presence of typical site backgrounds of about 80 mrem per year.« less
  • Confinement of alpha particles is essential for fusion ignition and alpha physics studies are a major goal of the TFTR, JET, and ITER DT experiments, but alpha measurements remain one of the most challenging plasma diagnostic tasks. The Pellet Charge Exchange (PCX) diagnostic has successfully measured the radial density profile and energy distribution of fast (0.5 to 3.5 MeV) confined alpha particles in TFTR. This paper describes the diagnostic capabilities of PCX demonstrated on TFTR and discusses the prospects for applying this technique to ITER. Major issues on ITER include the pellet`s perturbation to the plasma and obtaining satisfactory pelletmore » penetration into the plasma.« less
  • TFTR will be operated initially with ohmic heating only. During the first year, as additional equipment comes into operation, the plasma parameters will improve with a plasma current of about 1 MA anticipated before installation of neutral beam heating. The diagnostics described in this paper provide the information necessary for interpreting plasma properties and for verifying diagnostic interfaces for the full diagnostic system of which these diagnostics are a subset. A further, but less important, objective is that initial diagnostics be installed easily, because of the short time scheduled for this activity between tokamak vacuum tests and first plasma. Themore » diagnostics selected for initial operation of TFTR are listed with a statement of function and status at first plasma. The initial configuration of TFTR is briefly described and the general arrangement of diagnostics for first plasma is illustrated.« less
  • The Multichannel Far Infra Red Interferometer (MIRI) for TFTR employs phase comparison of 119 micrometer radiation in a Michelson (double pass) configuration for measurement of plasma electron density. MIRI accommodates up to ten vertical probing beams approximately evenly spaced across the plasma minor diameter. To reduce relative movement of critical components of these diagnostics, a stiff, damped, isolated structure was designed. Long-term drifts such as thermal effects and creep are compensated just prior to the measuring interval. The structure is designed to provide short term stability with excitation from machine electromagnetic fields and building vibration during the nominal one secondmore » measuring period. The design process allowing for this stability was aided and optimized by using dynamic applications of the finite element method.« less