The Accelerator Production of Tritium (APT) project will employ a high power proton accelerator to generate neutrons in a spallation target for the production of tritium. This paper will describe major attributes of the safety of this facility. 1 fig

Darby, J.

Edwards, J.

Lowrie, B.

Miller, L-A.

Rose, S.

Schweitzer, E.

UNT Digital Library

. LA-IJR- 96-1980 Title: Author@): Submitted to: N A T I O N A L  L A B O R A T O R Y  SAFETY OF SPALLATION SOURCES I N  THE ACCELEFXI’OR PRODUCTION OF TRITIUM J. Edwards, B. Lowrie, L. Miller, S. Rose, E. Schweitzer, J. Darby American Nuclear Society, Washington, DC, November 1996 Los Alamos National Laboratory. an affirmative action/equal opportunity empldyer, is operated by the University of California for the US. Department of Energy under contract W-7405-ENG-36. By acceptance of this article, the publisher recognizes that the US. Government retains a nonexclusive, royalty-free license to publish or reproduce the published form of this contribution, or to allow others to do so, for US. Government purposes. The Los Alamos National Laboratory requests that the publisher identify this article as work performed under the auspices of the US. Department of Energy. Form No. 836 R5 ST 2629 1 OB1 DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or use- fulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any spe- cific commercial product, process, or service by trade name, trademark, manufac- turer, or otherwise does not necessarily constitute or imply its endorsement, recorn- menhtion, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document. WYL 13A-lW bUbbba423liK Z /  b , 0- 3-30 i 1a;aa i 3 U Y 1  131 * 13H-lU c t  tA-uR- # C w n 9 $  w * .  c Safety of Spallation Sources in the Accelerator Production of Tritium Jack Edwards Los Alarnos National Laboratory MS K55l Los Alamos, New Mexico 87545 jedwardsQlanl.gov Bob L o d e  Westinghouse Savannah River Company Le- Miller Sewell Rose Los Alamos National Laboratory Eric Schweitzer Department of Energy John Darby Los Alamos National Laboratory 505 667-9062 I Sandia National Laboratory The Accelerator Production of Tritium (APT) project will employ a high power proton accelerator to generate neutrons in a spallation target for the production of tritium, This paper wiIl describe major attributes of the safe9 of this faciliv. The spallation target has b&n designed to maximize the production of tritium, which includes minimizing the nonproductive structures and coolant in the path of the proton beam. This results in a system design that has critical performance requirements during normal operation and accident conditions. Whilc a spallation target has - no fissionable material, there is a buildup of radioactive material from neutron activation and spallation products, When the proton beam is shut down, the power falls very quickly to residual heat levels that are el% of the full power value. LANL 'I'SA-1 lJ+ The authorization basis for APT is expected to be approved by United States Department of Energy (DOE) on the basis of thc DOE system of orders and regulations. To follow the DOE requirements for APT, the preparation of a Safety Analysis Report (SAR) will be required. The SAR documentation will be based on evaluating the hazards following the methodology of DOE-STD- 3009-94, "Preparation Guide For US. Department Of Energy Nonreactor Nuclear Facility Safety Analysis Reports." Preiiminary hazards analyses have been performed for the accelerator, the target/blanket (T/B), the tritium extraction facility, and the balance of the plant- From the point OF view of risk to the public, the T/B has the most significant radioactive inventory and potential release mechanisms. Accidents have becn identified along with potential prevention and mitigating systems. In this paper we will describc the major accident- sequences, Emphasis will be placed on examining the systems behavior of the target blanket protection systems. The APT target uses short, small diameter (0.32 an &am. x 20 cm) tungsten rods in: tightly packed bundles. The bundles are placed in a short segment of stainless steel tubing. Ten bundles are arranged horizontally to resemblc a ladder with the vertical legs of the ladder providing supply and return for the coolant. There are 10 ladders in the target (Fig. 1). The hazards for the T/B are dominated by events leading to damage and target cooling system breach. The primary accidents with the potential to cause these consequences are loss-of-coolan t-accidents (LOCAs) and loss-of- flow-accidents (LOFAs). -* There are two classes of LOCAs. The first occurs in the external piping for which case the tungsten neutron source remains flooded and the decay heat is removed by the residual heat removal (RHR) system. For the second class of LOCA, which is inside the cavity with a break low in the ladder, there are several mechanisms that could cause the liquid to be lost in a rung or rungs. During accident conditions, the safety systems design objective will be to keep the tungsten from drying out. The L O U  mitigation under these conditions will depend on a cavity flood system and the RHR system. This case will prove to be the most challenging to analyze, and experimental work may be required. Loss-of-flow-accidents will be in the anticipated events category with a frequency of - W 1 f y r .  The normal protection for these events will be to trip the beam, and then heat will be removed by the RHR system in either forced flow or by natural circulation. A concern is a LDFA with a failure to trip the beam. In a safety-grade, two-out-of-four logic protection system, the J * I u- a-a0 I 13.51 I 3 U 3 0 0 3 ~ L 3 2 1 f f  a/ 0 unreliability would be in the range of lo4 to lo5. The probability of the LOFA without a bcam trip will therefore still be in the range of credible events, It: will be a design requirement that thc beam trip have two separate beam trips that are completely independent, that rely on diverse conditions to detect a beam trip condition, and that affect the trip of the beam in diverse ways. Challenges The design of the APT system is a challenging effort but will not require a departure from standard engineering practice. The design of the safety features is proceeding in concert with the design for normal operation. The principles involved are well understood, but the uniqueness of the design introduces many system interrelationships that require thoughtful analysis and design. WYL I>A-lU+ 2 a 0 H 

Safety of spallation sources in the accelerator production of tritium

https://digital.library.unt.edu/ark:/67531/metadc674385/m2/1/high_res_d/392760.pdf

Safety of spallation sources in the accelerator production of tritium

Abstract

Similar works

Full text

Available Versions

UNT Digital Library