- RAr ¥ OAK RIDGE NATIONAL LABORATORY operated by UNION CARBIDE CORPORATION w for the U.S. ATOMIC ENERGY COMMISSION ORNL- TM- 733 (Revised) COPY NO. - ég DATE - August 3, 1965 MSRE DESIGN AND OPERATIONS REPORT Part VI OPERATING SAFETY LIMITS FOR THE MOLTEN-SALT ' REACTOR EXPERIMENT S. E. Beall R. H. Guymon . " ¥ Co r i e el 0 Ve 0w d . o ! - s e g e ¥ NOTICE This document contains information of a preliminary nature and was prepared primarily for internal use at the Oak Ridge National Laboratory. It is subject to revision or correction and therefore does not represent a final report. The information is not to be abstracted, reprinted or otherwise given public dis- semination without the approval of the ORNL patent branch, Legal and infor- mation Control Department. LEGAL NOTICE This report was prepared as an account of Government sponsored work. Neither the United States, nor the Commission, nor any person acting on behalf of the Commission: A. Mekes any warranty or representation, expressed or implied, with respect to the accurecy, completeness, or usefulness of the information contained in this report, or that the use of any informaotion, apporatus, method, or process disclosed in this report may net infringe privately owned rights; or B. Assumes any ligbilities with respect to the use of, or for damages resulting from the use of any information, apparatus, method, or process disclesed in this report. As used in the above, "person acting on behalf of the Commission’ includes any employee or contractor of the Commission, or employee of such contractor, to the extent that such employee or contractor of the Commission, or employee of such contractor prepares, disseminates, or provides access to, any information pursuant to his smployment or contraet with the Commission, or his employment with such contracter. ~%- MSRE DESIGN AND OPERATIONS REPORT Part VI OPERATING SAFETY LIMITS FOR THE MOLTEN-SALT REACTOR EXPERIMENT S. E. Beall R. H. Guymon This document has been prepared at the request of the U. S. Atomic Energy Commission to set the limits for various parameters related to the Molten-Salt Reactor Experiment. In some cases the limits report the level at which the reactor will be shut down by automatic monitoring devices. In all cases the reactor operators are obligated to take steps intended to correct a parameter which is temporarily outside the specified range indi- cated herein. 1.0 Contaimment 1.1 Leakage from the primary system as indicated by the reactor and drain-tank-cell air activity will not exceed the equivalent of 4 liters of salt after 120 days of operation at full power, as estimated in the case of the Most Probable Accident.l Off-gas activity release will be limited to fission-product concen- trations averaging less than 1.5 x ZLO-LL uC/CC in the stack. Fission product release will be monitored by radiation monitors on the off-gas lines and at the stack. The cover-gas supply pressure will be kept at 30 psig or greater and the leak-detector system pressure above 50 psig to help pre- vent excessive exposure to operating personnel, as specified in Chapter 0524 of the AEC Manual.5 1 S. E. Beall et al., "MSRE Design and Operations Report, Part V, Reactor Safety Analysis Report," USAEC Report ORNL TM-732, Ozk Ridge National Laboratory, August 1964. 2Based on 5 x 10"9 uc/cc as permissible concentration at_ground level downstream of the stack. An atmospheric dilution of 0.5 x 107 is assumed. 5Chapter 052k, "Standards for Radiation Protection.” 1.0 2.0 Containment (continued) 1.3 The radioactivity in the reactor cell service lines will be maintained at a level sufficiently low to prevent excessive exposure to personnel, as specified in Chapter 0524 of the AEC Manual. 1.4 The pressure in the reactor and drain tank cells will be main- tained below atmospheric pressure during reactor operation. 1.5 The maximum reactor and drain-tank-cell leak rate will not be allowed to exceed 1% of the cell volume per day, calculated for the conditions of the Maximum Credible Accident.l The in- leakage rate will be determined at least once per week. 1.6 The maximum vapor-condensing system pressure (under nonaccident conditions) will not exceed 3 psig. 1.7 The building high-bay pressure will be maintained at slightly less than atmospheric pressure (~0.1 in. HBO) during all oper- ations in which the high bay serves as the secondary contain- ment. 1.8 The ventilation system filters will be tested at least annually and after each change of filters. 1.8.1 The measured efficiency of the filters must be greater than 99.9% for 0.5 p and larger particles, as indicated by the standard dioctylphthalate test. Fuel System 2.1 The maximum steady-state power level is 10 Mw (administrative limit). 2.2 The power level for safety-rcd scram trip is 15 Mw or less. 2.3 The temperature level for safety~rod scram trip is less than 14000F. Adjustment of the trip between 1300 and 1400°F will require administrative approval. 2.4 The maximum fuel system cover-gas pressure is 50 psig. 2.0 N O ) 2.6 2.7 no \O Fuel System (continued) The maximum salt fill rate while filling the core 1s 1.0 ft5/min. 235 The maximum amount of U which will be added at one time 1is 120 g. During cperation fuel will only be added through the sampler enricher. The maximum concentration of fissionable material in the fuel salt will not exceed by more than 5% the minimum required Tor full-power operstion at 1200°F with equilibrium xenon and the control rods poisoning 0.6% Sk/k. The fuel salt will be sampled and the concentration measured at least once per week. At no time during critical operation of the reactor will the re- activity anomaly be allowed to exceed 0.5% $k/k. A "reactivity anomaly" is defined as a deviation from the reactivity which is expected on the basis of measured reactor physics constants and calculated effects of burnup and fission product accumulation. A positive period of 1 sec or less will cause a safety-rod scram. Coolant System 3.1 b,1 L, 2 L,z The maximum coolant system cover-gag pressure is 50 psig. Control Rods The normal complement of control rods 1s three, of which two are reguired to scram for safety action. The maximum scram time (time from initiation of signal until a rod is on the seat) is 1.3 sec. The rod speed (motor powered) is 0.5 ! 0.05 in./sec. This speed permits maximum reactivity additions in "start" of 0.1% $k/k per sec and in "run" of 0.05% S$k/k per sec. The scram time of the rods will be checked before each fill with fuel salt. 5.0 7.0 6. Nuclear Control and Safety Instrumentation 5.1 5.2 5.5 5.4 9.5 All nuclear safety instrumentation will be checked for proper operation before each fill. A minimum of two safety-level channels will be in service during reactor operation. A minimum of two reactor fuel outlet temperature signals will be in service during reactor operation. A minimum of one fission chamber with count-rate circuilt must be in operation during startup filling operations. A minimum of two positive period safety channels will be in service during reactor operation. Personnel Radiation Monitoring 6.1 Radiation level monitors A minimum of two perscnnel radiation monitors will be in oper- ation at all times, one in the high-bay area and one in the control-rcom area. Air monitors A minimum of two air activity monitors will be in operation at all times, one in the high-bay area and one in the office— control-room area. Personnel and Procedures T.1 Personnel qualifications The reactor will be operated only by qualified personnel ap- proved by the Chief of Operations. It will be operated in con- formance with documented operating procedures which, in no in- stance, designate authorization to operate the reactor in excess of any operating safety limits listed above. 7.0 8.0 Personnel and Procedires 7.2 The minimum staff requirement for operation during any shift is that at least orie supervisor and two technicians will be on duty during reactor operation. The control room will not be left un- attended while fuel is in the reactor vessel. Experimental Limits Experiments will be conducted within the limits specified in this report. Experimental procedures will be approved in advance by the Head of the Operations Department, Oak Ridge National Laboratory Reactor Division, or his authorized assistant. lO. 2l 28. \O Co—1 Ohvl AW o - Q= = F L. o Jo B. H. B. L. e » L . EEEEREE PSP SO PN NEQROP I IR @OQZH?JITIEUH'_UZEQZE{?UUJ.’I:"U*UEU 65-82. 83-84. 86-89: 90. 9L. Adamson . Affel . Beall Blankenship . Blumberg Boch Borkowski Briggs Burger Cottrell Crowley Culler Engel Epler Fraas Gabbard Gallaher Grimes Guymon Harley Haubenreich Holt Hudson Kasten Krakoviak Lindauer Lundin Lyon MacPherson . McCurdy McDonald ORNL-TM-733% REVISED Internal Distribution 2. H. McDhuffie %3%3. C. K. McGlothlan 3h, A, J. Miller 35. R. L. Moore 36. H. R. Payne 3f. A. M. Perry 38. H. B. Piper 39. J. L. Redford 40. H. C. Roller 41. M. W. Rosenthal 4o, H. Savage 4%3. Ann Savolainen Ly, D. Scott, Jr. 45. M. J. Skinner L6, A. N. Smith 47. I. Spiewak 48. R. C. steffy 49, A. Taboada 50. J. R. Tallackson 51 R. E. Thomas 52. D. B. Trauger 53. W. C. Ulrich 54, B. H. Webster 55. A. M. Weinberg 56. M. E. Whatley 57. G. D. Whitman 58-59., Central Research Library 60-61. Y-12 Document Reference Section 62-64. Laboratory Records Department 65. Laboratory Records, RC 66. C. E. Larson 67. S. J. Ditto External Distribution Division of Technical Information Extension, DTIE D. F. Cope, Reactor Division, AEC, ORO R. W. Garrison, AEC, Washington H. M. Roth, Division of Research and Development, AEC, ORO W. L. Smalley, Reactor Division, AEC, ORO M. J. Whitman, AEC, Washington