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Estimate of radiation release for MIT research reactor during design basis accident

IP.com Disclosure Number: IPCOM000128035D
Original Publication Date: 1998-Dec-31
Included in the Prior Art Database: 2005-Sep-14
Document File: 6 page(s) / 21K

Publishing Venue

Software Patent Institute

Related People

Li, Qing: AUTHOR [+3]

Related Documents

http://theses.mit.edu:80/Dienst/UI/2.0/Describe/0018.mit.theses/1998-201: URL

Abstract

During a postulated design basis accident at the MIT Research Reactor (MITR), radioactive fission products may be released from melted fuel plates into the containment. To comply with regulations, the whole-body dose and thyroid dose at the boundary of the exclusion area as a result of this accident are determined. The fractions of the fission products contained in the fuel that are released through the reactor coolant system (RCS) into the containment are determined based on current regulations, experimental tests, and results from TMI-2 accident. After the fission products are released into the containment, a portion may be released to the outside through a containment crack or the stack. Also, the portion retained in the containment would contribute to the external gamma dose. The calculated dose due to atmospheric release depends on the source strength, the meteorological conditions, and the dispersion model. For containment crack release and stack release, different dispersion models are used according to pertinent regulatory guides. The gamma, dose through penetration or scattering depends on the structure of the containment shielding and is determined analytically under appropriate approximations. Because the MITR is considering upgrading its power level, results at power levels from 5 to 10 MW are determined. At 5, 6, 7, 8, 9, 10 MW, the whole body doses at the back fence (8 meters away from the MITR) are 0.644, 0.764, 0.885, rem respectively; the thyroid doses at the back fence are 0.112, 0.135, 0.157, 0.179, 0.202, 0.225 rem respectively; the whole body doses at the front fence (21 meters away from the MITR) are 0.887, 1.06, 1.22, 1.39, 1.56, 1.72 rem respectively; and the thyroid doses at the front fence are 0.112, 0.134, 0.156, 0.179, 0.201, 0.224 rem respectively. The results show that even under conservative assumptions, the released doses for power levels from 5 MW to 10 MW are well below the regulatory limit - 25 rem for whole body and 300 rem for thyroid.

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 This record is the front matter from a document that appears on a server at MIT and is used through permission from MIT. See http://theses.mit.edu:80/Dienst/UI/2.0/Describe/0018.mit.theses/1998-201 for copyright details and for the full document in image form.

Estimate of Radiation Release for MIT Research Reactor During Design Basis Accident

by

Qing Li
Submitted in partial fulfillment of the requirements for the degree of Master of Science in Nuclear Engineering

at the Massachusetts Institute of Technology

May 1998 [June 1998]

SIGNATURE OF author: [[signature omitted]]

Department of Nuclear Engineering

May 8, 1998
CERTIFIED BY: [[SIGNATURE OMITTED]]

John A Bernard Director, MIT Nuclear Reactor Laboratory Thesis supervisor Jacquelyn C. Yanch

Professor, Nuclear Engineering Department Thesis Supervisor ACCEPTED BY: [[SIGNATURE OMITTED]]

Lawrence M. Lidsky Chairman, Department Committee on Graduate Students ARCHIVES MASSACHUSETTS INSTITUTE OF TECHNOLOGY LIBRARIES AUG 18 1998

Massachusetts Institute of Technology Page 1 Dec 31, 1998

Page 2 of 6

Estimate of radiation release for MIT research reactor during design basis accident

Estimate of Radiation Release for MIT Research Reactor During Design Basis Accident

by

Qing Li

Submitted to the Department of Nuclear Engineering on May 8, 1998, in partial fulfillment of the requirements for the degree of Master of Science in Nuclear Engineering

Abstract

During a postulated design basis accident at the MIT Research Reactor (MITR), radioactive fission products may be released from melted fuel plates into the containment. To comply with regulations, the whole-body dose and thyroid dose at the boundary of the exclusion area as a result of this accident are determined.

The fractions of the fission products contained in the fuel that are released through the reactor coolant system (RCS) into the containment are determined based on current regulations, experimental tests, and results from TMI-2 accident.

After the fission products are released into the containment, a portion may be released to the outside through a containment crack or the stack. Also, the portion retained in the containment would contribute to the external gamma dose. The calculated dose due to atmospheric release depends on the source strength, the meteorological conditions, and the dispersion model. For containment crack release and stack release, different dispersion models are used according to pertinent regulatory guides. The gamma, dose through penetration or scattering depends on the structure of the containment shielding and is determined analytically under appropriate approximations.

Because the MITR is considering upgrading its power level, results at power levels from 5 to 10 MW are determined. At 5, 6, 7, 8, 9, 10 MW, the whole body doses at the back fence (8 meters away from the MITR) are 0.644, 0.764, 0.885, rem respectively; the thyroid doses at the back fence are 0.112, 0.135, 0.157, 0.179, 0.202, 0.225 rem respectiv...