Existing reactor expansion study basis

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REVIEW OF STUDY BASIS 4 STUDY PROBLEM ASSIGNMENTS I0 B. Basic Analytical and Engineering Studies i0 D. Process Water System Studies SCHEDULES AND MANPOWER ESTIMATES 17 Table I - Expansion Study Basic Parameters 8 Table II - Expansion Study Case Tabulation 9 Table III - Study Problem Assignment Summary 16 Figure I - Proposed Study Schedule and Manpower Estimates 18 Table IV - Existing Reactor Expansion Study 20 Estimated Manpower Requirements

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The latest HAPO Five Year Program review, HW-59633. forecasts substantial increases in Pu production from the eight existing Hanford reactors over the next several years. These production increases would be attained by a combination of several methods which include increased reactor power levels resulting from higher process water flow rates and coolant bulk outlet temperatures, improved tlme operated efficiency, higher conversion ratios, and reduced transient reactivity losses. In order to provide a realistic basis for budgeting to meet these or other increased production goals, it is necessary that a study program be undertaken to determine in general terms the plant changes required to support these forecasted levels, to evaluate the economic and technical feasibility of achieving the process conditions, and to present an integrated program for achieving these objectives. This study program will necessarily consider the interrelated effects of a number of various facets of reactor and water plant process conditions, operational requirements, and proposed development programs. The purpose of this document is to present a plan for the execution of the proposed study. Included in this outline are a review of the basic study considerations, problem assignments and schedules, and manpower and cost estimates for the performance of the study. REVIEW OF STUDY BASIS Increase in Pu production from the existing reactors may be achieved by several methods including increased reactor power levels, improved operational and process efficiencies, and higher conversion ratios. The achievement of increased reactor power levels will require consideration of four basic interrelated programs; which I. Increased Process Water Flow Rates 2. Increased Bulk Outlet Water Temperature 3. Improved Fuel Element Performance @. Installation of Zirconium Alloy Process _foes The achievement of increased operational and process efflciencies may be accomplished by a number of methods including zirconium alloy process tube installation, operational charge-discharge, improved reactor instrumentation and control systems, improved fuel element performance, reduced operational error, and improved maintenance techniques and programs. Since a number of these programs will proceed independently of any reactor power level increa_seon their own merits, consideration will be given in this study only to those items which are related to a general power level increase. This does not mean that consideration will be given only to the achievement of process flow and temperature _ncreases, but rathe_ that items of a purely operational or maintenance nature which have independent Justification and are not directly related to increased power levels will net be included in rh. study. Also independent process _mprovement programs such as operational charge-discharge which are Justified on their own merits will be excluded from the scope of thls study.

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Higher Pu conversion ratios may be achieved by several methods having a direct effect on reactor operating conditions, such as the use of zirconium alloy process tubes, fuel element design, and front to rear flattening. These factors will necessarily be considered in any study or evaluation of increased reactor process conditions. The items discussed in this section of the report are taken as the fundamental process variables which will be considered in the study program. There are a number of other process conditions which must be considered in a specific study case but are dependent variables of the basic variables. A number of the dependent items will be discussed in the following sections of this report. lt is recognized that it may be necessary to revise some of the specific study conditions as the study progresses and gre=ter insight into various process limits is achieved. By the prosecution of a number of parallel study programs and the Judicious selection of process conditions for final correlation, a reasonable evaluation of the short term potential of the existing reactors can be obtained within available time and manpower limitations. There are a number of other modifications of existing process conditions which potentially could be included within the scope of any long term reactor modification program such as overboring of the reactor graphite process channels! however, due to the limited technology which is available to support items of this nature they have been excluded from consideration in this study program. Several of the basic variables selected for use differ from those normally used in a reactor optimization study; however, since the fullest use will be made of existing process facilities, the capability of these facilities will have considerably more influence on the study results than more basic reactor process considerations. The basic variables selected for study are as follows: I. Process Water Flows At the present time, the reactor process water flow rates are approximately Recent prelimi_ary studies of the existing reactor process water system capabilities(1)(2) have indicated that a substantial increase in flow rates may be achieved for relatively modest expenditure of funds. However, little information is available regarding the feasibility of achieving additional flow increases beyond those previously studied. In order to more fully provide information regarding additional flow increases,proce,s flow rates of up to approximately 120 percent of existing flow rates will be studied. The K reactors will not be includnd in this study program since sub

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Some minor adjustment of the specific flow rates selected may be.required during the progress of the study to make the fullest utilization of At the present time, the bulk outlet water temperature of the various reactors is approaching 93oC, with plans established to increase this limit to 95oC in the near future. Significant further bulk temperature increases will probably requir_ extensive alteration of the existing r,:_face piping and effluent system to provide some degree of pressurization_J. There appears to be little long term incentive for the achievement of bulk outlet temperatures above the llO.120oC range due to fuel element corrosion rates and available technology Will limit this temperature to a lesser value for the immediate future. The bulk temperature condition selected for study will provide for a review of the modification required to the reactor piping and effluent systems to support a further increase in bulk outlet temperatures and still be.within reasonable extrapolations of current technology. The study of this condition will also provide an engineering evaluation of the physical changes required to support a further temperature increase at a later date. The increased effluent temperature conditions selected forstudy are as follows: Plans are currently under way for the trial replacement of a number of the presently installed aluminum process tubes with zirconium alloy tubes of the same outside diameter in several of the reactors. The installation of zirconium process tubes will provide several _)nefkts, such as: reduction of process tube r_placement outage requirements, the possibility of obtaining increased process water flow rates with _resent ty_es of fuel elements due to the larger flow area available, an increase in the conversion ratio and a reduction in enrichment requirements with she utilization of larger fuel elements. These potential benefits may be further increased by using the reactor process channels to accommodat, ip_ger diameter process tubes of either aluminum or zirconium. A modest _ncrease in process tube outside diameter may b_ achieved by replacement of th. existing _unbarrels with gap between the process tube and the graphite for a tube of larger o,.tsld_ diameter. Any program,for _nlargeme:,tof the present process channels to permit tl_ use of substantially larj{erprocess tubes is considered to bn beyond the scope of this study. Th_ study conditions may be summarlz,,das follows:

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Base Case Study Case Arej Aiuminum Aiumlnum Zirconium present channels Maximum OD in The successful attainment of any increase in reactor power level is highly dependent upon fuel element performance. Modest increases in reactor power levels will probably be achieved with only minor modifications to the present I&E types of fuel elements. It appears to be reasonable to base this study upon the use of self supported I&E types of fuel elements as reasonable extrapolations of current technology. Since overall reactor system economics are very dependent upon fuel performance, several levels of fuel performance will be evaluated. Base Case Study Condition_ Present Quality Fuel performance evaluated at pessimistic and optimistic The above conditions describe the basic process conditions which will be considered in this stuc_v. A summary of these conditions is contained in Table I and a tabulation of specific,study cases is presented in Table II. The K areas have been included in this listing so as to provide for the evaluation of zirconium process tubes, bulk temperature increases, and fuel element performance although further expansion of the process water systems is not contemplatedat this time. There are a number of technical bases, process requirements, operational problems and plant modifications which must be reviewed and evaluated in any study regarding the achievement of increased reactor power levels. The following section of this report, the purpose of which is to provide a basis for the evaluation of manpOwer and time requirements for the performance of this study and the preparation of specific study assignments,is a summary and brief discussion of a number of these considerations. Any program recommendations resulting from this study will be an integrated program which considers all facets of operating requirements and The proposals presented at the end of this study program will necessarily be rather general in nature, with more detailed consXd,ration given to the various items before any final project action is initiated.

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1. Process Water Flow 3. Process Tubes Aluminum Aluminum Zirconium present channels maximum diameter 4. Fuel Element Supported I&E Self supported I&E - 2 levels Uniform Cor- of performance

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STUDY PROBLEM ASSIGNMENTS To evaloate the feasibility of attaining increased reactor power levels and to provide a basis for the performance of the design and economic studies the Joint efforts of Facilities Engineering and Research and Englneerlng personnel will be required° The contributions of these groups will be in their particular fields of responsibility, and the ser_rlcesand facilities available in other HAPO components will also be utilized to som_ extent. The following items as listed are not proposed to be sr,all inclusive listing, but rather as a tabulation .ofproblem asslgnmen_s whlzh will be included in the study program and which will be subject to some revision as t_ study progresses. The problem assignments have been grouped in general fields of .*interestrather than by a functional activity type of listing° It is expected that topical reports will be prepared upon each of the various study assignments as the work progresses. However, the rather extensive task of editing and compiling the information generated in this study into a final summary tcp.rr will necessarily be performed after completion of the various individual assignments. Considerable Judgment will h_e to be excercised in correlating the recommendations ar,_ conclusions presented in the individual reports for management consideration° Evaluation of the technical feasibility of achieving the proposed increased reactor power levels in view of current reactor technology and planned development programs will be performed to provide a basis for management decision regarding any proposed project recommendations. Items which would be considered in these evaluations would include fuel element productlonand performance, graphite shifting and contraction, reactor llfe, reactor safety, ultimate specific tube powers, process tube integrity, nuclear stability, and basic operational philosophy. lt will be necessary to perform a number of economic analyses which will correlate the results of the process condition optimization, the proposed plant modification capital costs for the various study cases and the resulting operating cost char_es in order %o determine the more promising plant modifications from an economic standpoint and to develop justification for the proposed capital funds expendlture. This activity will necessarily be one of the later phases of the study program, but considerable early effort will be requlred in developing ba_i : data

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To provide a basis for the economic analysis, cost estimates of the various plant modifications which are proposed will be prepared, based upon the results of the various engineering studies. As part of the economic analysis consideration will be given to the reactor outage time required for the performance of the proposed plant modifications and the scheduling of the same. Since the estimates of outage time will have considerable effect on over-all program economics they must be given sufficient attention to ensure that the estimates prepared are realistic. 5. Basic Analytical Studies A number of analytical studies of the proposed process conditions listed previously will be required to determine specific reactor performance criteria as a basis for the various engineering and economic studies which will be performed. Included in these studies will be basic physics evaluations, fuel element design and performance evaluation, variations in fuel exposure, enrichment, specific tube powers, flux density, moderator temperatures, fuel costs and product values, conversion ratio, and other items of a slmilar nature. Suitable computer programs are generally available for the performance of these studies or programs are available which can be adapted to the study requirements. Included in these studies as a specific item will be the evaluation of alternative enrichment patterns, such as spike vs. uniform enrichment, axial flattening as well as side-to-side flattening, and fringe blanket poisoning. 6. Reactor Transient Cooling Requirements Reactor transient and shutdown cooling requirements will be establisheo so as to provide a basis for the design of the process water system modifications and the evaluations of the various process water back-up C. Reactor Process Unit Studies I. Nuclear Process Unit Studies A problem becoming relatively more serious with increasing reactor power levels is that of reactor control. Evaluations of both operat_onal and shutdown control system requirements will be made to det_rmlne the system modlflca%ions if any which will be requlred at th_ problem o£ total reactor control upon loss of water when zirconium,process tubes are installed in the reactor. In establishing the necessary control system changes, consideration will be given to the

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use of auxiliary control systems such as poison columns, poison splines, and axial displacement columns for achieving adequate operational control and reducing transient reactivity losses. The development of speed of control requirements for reactor shutdown will be included in this problem assignment. 2. Water Quality Requirements Reactor process water quality requirements at the proposed operating conditions will be established so as to provide a basis for the design of the water treatment system modifications. The water quality requirements will reflect fuel element performance and process tube and effluent system piping corrosion problems. An evaluation of reactor graphite distortion, contraction, venting requirements, and problems of a similar nature under the proposed operating conditions will be required. This study will also by its nature consider the basic problem of ultimate reactor life. The establishment of gas system requirements will also be a responsibility of this assignment. 4. Thermal and Biological Shields A study of the current biological shield deterioration and deflection problems under the proposed operating conditions will be made to …