b"“-"q. i —— - -a.._,"_uj EJ. OAK RIDGE NATIONAL LABORAT operated by UNION CARBIDE CORPORATION for the - U.S. ATOMIC ENERGY COMMISSION ORNL- TM-733 C L MSRE DESIGN AND OPERATIONS REPORT Part VI OPERATING SAFETY LIMITS FOR THE MOLTEN-SALT EXPERIMENT S.E. Beall R.H. Guymon £ QETAINED. RELEASE TQE OvVED. PROGEDURES THING SECTION. PATENT CLEARANC THE PUBLIC 1S APPR ! ARE ON FILE iN THE RES 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. LEGAL NOTICE This report was prepared as an account of Guvernment sponsored work, Neither the United States, nor the Commission, nor any person acting on behalf of the Commission: A. Makes any warranty or representation, expressed or implied, with respect to the accuracy, completeness, or usefulness of the information contained in this rasport, or thot the use of any information, aepporosus, method, or process disclosed in this report may not infringe privately owned rights; or B. Assumes any liabilities with respect to the use of, or for damages resulting from the use of any information, apparatys, method, or process disclosed in this report. As usad 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 employse of contractor of the Commission, or employee of such contractor prepares, disseminates, or provides access to, any information pursuant to his employment or contract with the Commission, or his employment with such contractor. ORNL-TM-733 Contract Wo. W-T405-eng-26 Reactor Division MSRE DESIGN AND OPERATIONS REPORT Part VI OPERATING SAFETY LIMITS FOR THE MOLTEN-SALT REACTOR EXPERIMENT S. E. Beall R. H. Guymon OAK RIDGE NATIONAL LABORATORY Ozk Ridge, Tennessee operated by UNION CARBIDE CORPORATION for the U. S. ATOMIC ENERGY COMMISSION MSRE DESIGN AND OPERATIONS REPORT Part VI OPERATING SAFETY LIMITS FCOR 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 L 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 lO-u/uc/cc in the stack.2 Fission=-product release will be monitored by radiation monitors on the off-gas lines and at the stack. 1.2 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.” lS. E. Beall et al., "MSRE Design and Operations Report, Part V, Reactor Safety Analysis Report,'" USAEC Report ORNL TM-732, Oak Ridge National Laboratory, August 196k, 2Based on % x lOmg)pc/cc as permicsible concentration at _ground level downstream of the stack. An atmospheric dilution of 0.5 x 10° is assumed. 5Chapter 0524, "Standards for Radiation Protection.” 1.0 A O Containment (continued) 1.5 1.5 1.6 no no no AN The radicactivity in the reactor cell service lines will be maintained at a level sufficiently low to prevent excesslve exposure to personnel, as specified in Chapter 0524 of the AEC Manual. The pressure in the reactor and drain tank cells will be main- tained below atmospheric pressure during reactor operation. 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. The maximum vapor-condensing system pressure (under nonaccident conditions) will not exceed 3 psig. The building high-bay pressure will be maintained at slightly less than atmospheric pressure (&O.l in. HQO) during all oper- atlons in which the high bay serves as the secondary contain- ment. 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. System The meximum steady-state power level is 10 Mw (administrative limit). The power level for safety-rod scram trip is 15 Mw or less. The temperature level for safety-rod scram trip is less than 1400°F. Adjustment cf the trip between 1300 and 1400%F will require administrative approval. The maximun fuel system cover-gas pressure is 50 psig. no O L.0 5.0 Fuel System (continued) 2.5 P 2.0 The maximum salt fill rate while filling the core is 1.0 ftB/min. 55U which will be added gt one time is The maximum amount of 2 120 g. During operation 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 for full-power operation at 1200°F with equilibrium xenon and the control rods poisoning 0.6% {k/k. The fuel salt will be sampled and the concentration measured at least once per week. Coolant System 5.1 The maximum coolant system cover-gas pressure is 50 psig. Control Rods ho1 L.L The normal complement of control rods is three, of which two are required to scram for safety action. The maximum scram time (time from initiation of signal until a rod is on the sest) is 1.3 sec. . + . The rod speed (mctor 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% 4k/k per sec. The scram time of the rods will be checked before each fill. Nuclear Control and Safety Instrumentation 5.1 5.2 A\ N All nuclear safety instrumentation will be checked for proper operation before each fill. A minimum of two safety-level chambers will be in service during reactor operation. A minimum of two reactor fuel outlet temperature signals will be in service during reactor operation. O O 7'0 Nuclear Control and Safety Instrumentation (continued) 5.4 A minimum of one fission chamber with count-rate circuit must be in operation during stertup filling operations. Personnel Radiation Monitoring 5.1 Radiation level monitors A minimum of two personnel radiation monitors will be in oper- ation at all fimes, one in the high-bay area and one in the control-room ares. O .2 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 7«1 Personnel gualifications The reactor will be operated only by qualified perscnnel ap- vroved by