Regulatory Guide 3.6
| ML003740163 | |
| Person / Time | |
|---|---|
| Issue date: | 04/09/1973 |
| From: | Office of Nuclear Regulatory Research |
| To: | |
| References | |
| RG-3.6 | |
| Download: ML003740163 (8) | |
4/9174 U.S. ATOMIC ENERGY COMMISSION
REGULATORY GUIDE
DIRECTORATE OF REGULATORY STANDARDS
"ViSr Olt REGULATORY GUIDE 3.6 CONTENT OF TECHNICAL SPECIFICATIONS
FOR FUEL REPROCESSING PLANTS
I. INTRODUCTION
those dealing with administrative controls, must be included in the application but does not become part of In accordance with § 50.34 of 10 CFR Part 50. an the technical specifications. Technical specifications application for a construction permit for a production or cannot be changed without prior Commission approval.
utilization facility is required to include an identification and justilication for the selection of those variables, Section 50.36 of 10 CFR Part 50 sets forth conditions, or other items which are determined as a definitions and requirements relating to five categories result of preliminary safety analysis and evaluation to be for which technical specifications for fuel reprocessing probable subjects of technical specifications for the plants may be appropriate: (1) safety limits and limiting plant. Special attention should be given to those items control settings, (2) limiting conditions for operation.
which may significantly influence the final design. The (3) surveillance requirements. (4) design features, and objective in selecting probable technical specification (5) administrative controls. This document provides subjects is to identify those items that would require general guidelines for the development of technical special attention at the construction permit stage to specifications under each category. Exhibit I of this avoid the necessity for any significant change in design guide presents a suggested format for technical to support final technical specifications, e.g., particularly specifications for Categories 1, 2. 3, and 4, as listed those specifications that include technical operating above.
limits, conditions, and requirements imposed upon plant operation in the interest of the health and safety of the II. CONTENT OF TECHNICAL SPECIFICATIONS
public.
Technical specifications should include both The probable subjects for technical specifications technical and administrative matters. Technical and the corresponding justification proposed by an specifications related to technical matters should consist applicant for its plant are included in the Preliminary of those features (process variables, systems, or Safety Analysis Report (PSAR) and should be as components) of the facility that are of controlling complete as the status of the design permils, i.e.. to the importance to safety. In addition, technical fullest cxteiit possible, numerical values and other specifications related to technical matters should include pertinent data should be provided. effluent and environmental monitoring and specifications addressed to the attainment of "as low as In accordance with § 50.36 of 10 CFR Part 50. practicable" levels of releases and exposures. Technical each operating license for a production or utilization specifications related to administrative matters should be facility issued by the Atomic Energy Commission must addressed to those organizational and functional contain technical operating limits, conditions, and requirements that are important to the achievement and requirements imposed upon plant operation in the maintenance of safe operation of the facility.
interest of the health and safety of the public. The technical specifications are proposed by the applicant
1. Technical Matters
!*,r an operating license. After review by the AEC
'ýegulatory staff, they are modified as necessary before becoming part of the operating license. A statement of The identification of controlling features can be the bases or reasons for all specifications, other than accomplished by a thorough safety analysis of the Copies of published guides may be obtained by request indiclting the divisic-s USAEC REGULATORY GUIDES desired to the US. Atomic Energy Commiusson. Washington. D.C. 20646.
to describe and make available to the public Attention: Director of Regulatory Standards. Commints and suggestions 10f re issued Regulatory Guides improvemints*i$ these gudes are encOuraged and should be sent to the Secretary Regulatory staff of iplermensting specific parts of methods acceptable to the AEC of the Commission. U.S. Atomic Energy Commission, Washington. D.C. 20645.
the Cornsnission's regulations, to delineate techniques used by the staff in Attention: Chief. Public Proceedings, Staff.
euialuating specific problems or postulated accidents, or to tWovide guidance to applimants. Regulatory Guides are not substitutes for regulations and compliance The guides wre issued in the following ten broad divisions:
out in with them Is not required. Methods and solutions different from than set to the guides will be acmeptable if they provide a tbats for the findings requisite 1. Power Reactors 6. Products Ith, isuanci or continuance of a permit or license by the Commission. 7- Transportationi
2. Research and Test Reactors
3. Fuels and Mateirials Facilities
8. OcupEationm Health
4. Environmentat and Siting 9. Antitrust Pulshaid guides will be revised pcriodically, as appropriate, to accommodate 1
0. General
5. Materials and Plant Protection comments and to rellci new infoir*ation or e*oerience
facility based on current knowleuxe and understanding In the event of errors in operation or relatively
,of safety needs and techniques. The safety analysis minor malfunctions of equwpment, a condition of should determine: abnormal operation, as illustrated by the second block in a. The margins of safety dluring normal operations Figure 1, will exist. To prevent further progression of and transient conditions anticipated during the life of these circumstances, special operating proedures, the facility; and alarms, or automatic controls are usually provided. Even b The adequacy of structures, systems, and though these procedures and controls return the components provided for the prevention of accidents operating situation to normal, any radioactivity :hat was and the mitigation of the consequences of accidents. released to the cells must not reach the environment.
Hence, the further barriers must be functioning The performance of such an analysis should entail: adequately.
a. Detailed examination of structures, systems, and components with respect to their ability to meet The progression in Figure I illustrates the need to assigned objectives; develop specifications which will ensure that successive b. Evaluation of their ability to resist malfunction; barriers exist: that process controls, procedures, and c. Estimation of their ability to function reliably equipment are functioning as necessary to prevent despite malfunction of related structures, systems, or accidents and dispersal of radioactivity; and that systems components; and controlling the liquid and gaseous effluents, possess d. Determination and understanding of the sufficient reserve capacity not needed for routine conditions or circumstances relating to equipment or operation to control the results of any accidents. For process variables, under which each can no longer example, in a fuel reprocessing plant, the scrubbers, function properly. filters, and absorbers used to treat the offgas constitute a barrier to release of radioactive contamination to the The focal points for the analysis should be (1) the environment. As a prerequisite for facility operation, it design features that assure that radioactive materials will is necessary to specify the condition of operability of not be dispersed from the process equipment these systems. It is also necessary to specify survefllance (accidentally. or otherwise) and (2) the filters and and testing programs for these items to assure their barriers that prevent radioactive materials from reaching proper functioning.
the environment. These various successive barriers to the release of radioactivity form a defense in depth on which overall safety depends. "Defense in depth" carries a No barrier is perfect, and therefore sole reliance broader connotation than just that related to successive should not be placed on any single barrier to protect protective features to prevent release of radioactivity. public health and safety. However, careful attention to For example, the principle applies to control and alarm the maintenance of integrity and performance of each of instrumentation (i.e., redundancy and backup); to the barriers can substantially reduce the consequences of people, equipment, and procedural interactions; and to a serious accident. Therefore, technical and engineering review and audit by various groups at several levels of matters forming the subjects for technical specifications management. This is further illustrated in section IV of should be addressed to reasonable maintenance of each this guide in which the five categones of technical of the barriers.
specifications are discussed.
Surveillance of the site, by monitoring of the The relationships of the barriers to the operation of potential pathways of radionuclides through the a facility and to the conditions and characteristics that environment to man, provides added assurance that the lead to protection of the barriers are shown in Figure 1 integrity and performance of the barriers has been of this guide, which is a simplified diagram showing the adequate to protect public health and safety.
course of events which could lead to violation of one or more of the barriers. Conditions of normal operation are 2. Administrative Matters represented by the first block in Figure 1. To maintain these conditions, two important sets of circumstances With respect to administrative controls, the must exist (1) important process variables must be framework for technical specifications is based on four maintained in their normal ranges and (2) components principal functions that should be performed:
and systems of equipment must be operating properly. a. Operatior of the plant equipment;
b. Maintenance of equipment;
Process variables are maintained in their normal c. Record keeping; and ranges by use of standard operating procedures, and in d. Audits, reviews, and evaluation of operations
,;ome instances, by automatic control systems. (i.e., performance of both equipment and people).
Equipment which is necessary to operate or control the process is monitored throughout the operation, and While reprocessing plants may vary in size, character, and complexity, the safe operation of a s"meI c mpolnenis and systems are tested and checked during operation to assure that they are operating facility depends on an organization that includes people of various talents. For the organization to operate ct.riectly. successfully, there must be delegation of responsibility
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and authority. To ensure a safety consciousness 1. Safety Limits and Limiting Control Settings throughout the organization, management must provide safety standards and objectives as well as a procedural Specifications of this category apply to system that implements these. safety-related process variables which are observable and measurable (e.g., pressures, temperatures, flow rates, Important factors in such a system include the concentrations, volumes, and quantiti-1. Control of fol!owing: such variables is directly related to the performance and a. An organizational structure that provides a integrity of equipment and confinement oarriers.
clear definition of responsibility, authority, and accountability; Figure 2 of thib guide illustrates in a general way the b. Personnel with adequate technical ability, concepts of limits and their relation to normal experience, and training; conditions of plant operation.
c. Standards and limits within which the fuel reprocessing plant and auxiliaries must be operated; The safety limit for a given variable is a value of that d. Approved written procedures for all operations, variable at which one can say with confidence that no including procedures for abnormal and emergency serious consequences will occur. If the value of the conditions and procedures for review, approval, and variable were to reach this limit, no hazard to the public execution of changes to the process, equipment, or health and safety would exist even if all other variables procedure; were at the upper bounds of their operating ranges.
e. Thorough analysis of all unusual incidents;
f. Scheduled periodic review of the operation by Beyond the safety limit, and separated from it by a competent independent staff with a high level of finite margin, is a danger zone in which unacceptable authority; and consequences may occur or for which a safety analysis g. Prompt corrective action on deficiencies found has not been performed. Somewhere in this zone is a real during audits. limit which divides values that are certain to result in unacceptable consequences from those that will not.
III. BASES FOR TECHNICAL SPECIFICATIONS Usually, this limit cannot be precisely located because of uncertainties both in the acceptability criteria and in When a technical specification has been selected, the technical knowledge of the process, and because this bases for its selection and its significance to safety of limit is interdependent with the values of other variables.
"operation should be defined. This can be done by the Therefore, the safety limit for a given variable is chosen provision of a summary statement, in writing, of the after consideration of experience, experimental results, technical and operational considerations which justify interaction between variables, and all other pertinent the selection. The Safety Analysis Report (SAR) should plant characteristics, and is located conservatively within fully develop, through analysis and evaluation, the the bounds of knowledge. The margin noted as details of these bases. The physical format for technical "Allowance for Uncertainty..." in Figure 2 is intended specifications therefore assumes importance, since the to take into account the factors mentioned above. For collection of specifications and their written bases form example, consider the variables pressure, temperature, a document which delineates facility features that are and acid concentration in a dissolver. Pressure may be important to safety of operation, the reasons for their limited so that the dissolver offgas system does not importance, and their relations one to the other. become overloaded. Temperature and acid concentration may be limited at a certain stage of the process to Furthermore. as experience in operation and control reaction rate.
technical knowledge accrue, changes in technical specifications become desirable from time to time, and The practical result of this approach is that the the written basis for a specification provides for orderly transgression of a safety limit by a small amount would analysis and evaluation of such changes. Only the not produce unacceptable consequences. However, this specifications are binding upon the licensee. Bases are action would represent a significant and undesirable supporting information. departure from proper operation. To transgress a safety limit, significant equipment malfunction or failure or one or more significant deviations from operating IV. DEVELOPMENT OF TECHNICAL procedures, or both, would have to occur.
SPECIFICATIONS
At a level on the safe side of the safety limit, a The five categories for which technical specifica limiting control setting is selected. The region between tions are defined in § 50.36 of 10 CFR Part 50 have this setting and the safety limit should be sufficient to been derived from a consideration of factors that bear allow for alarms and for subsequent corrective action by on the use and maintenance of physical barriers in the automatic protective action controls or procedure operation of a facility. Additional categories may be systems to return the situation to normal or to shut the designated by the applicant. The following discussion process down before the safety limit is reached.
will examine and outline the development of technical Selection of the limiting control settings must take into specifications that must be covered. account response times, transient characteristics,
3.6-3
calibration uncertainties, and instrument reliabilities and readiness to assure continaied "afe operaticn and to inaccuracies. prevent a malfunction from developing into a severe accident situation. Examples of this type are emergenc.
Some examples of situations that should be power, emergency air, emergency steam, spare on-line considered are excess pressure or vacuum in a cell or ventilation fans, backup cooling water supplies, and fire glove box, high concentration of fissile material in an prevention systems.
extraction unit, high temperature of solvent systems, loss of coolant in a high-heat-generating system, and abnormal hydrogen concentration in an offgas system. A third type of equipment that requires performance and integrity specifications are the filters and barriers that must perform well routinely but must On the safe side of the limiting control setting lies the zone of normal operations. Allowance must be made also have some minimum reserve capacity to contain for the possibility that the value of the variable may large accidents. Examples of this equipment type. with transgress the normal zone occasionally due to the typical appropriate specifications, are iodine absorbers instrument drift, minor operatimnal errors, and normal and their minimum efficiency, main ventilation filters fluctuations in process or control characteristics. and their minimum efficiency, segregated or closed loop Therefore, a margin should be left between the normal cooling systems and their maximum leakage rate.
operating zone and the limiting control setting because ventilation system structures and their maximum of these factors. This is the "Operating Margin" shown backflow or leakage rates at some accident-generated in Figure 2. Usually, alarms or annunciators are provided pressure wave, and the building or process cell structures between the operating zone and the limiting control and their leakage rate at some pressure differential.
setting or the safety system action point to promote corrective action and to help prevent any significant b. Technical Conditions and Characteristics invasion of the safety margin.
Technical conditions and characteristics should be stated in terms of allowable quantities, e.g..
A result of proper relation between the safety limit or the limiting control setting and the normal operating temperature, pressure, mass of fissionable material in zone is that the limiting control setting should seldom be certain systems, concentration of radioactive material in exceeded and any safety system should seldom be certain systems, volume of fluid required in a system, chemical constitution of certain fluids, or allowable activated.
configurations of equipment.
2. Limiting Conditions for Operation As an example of an allowable quantity, the This category of technical specification covers two temperature of a cell containing solvent extraction general classes, (a) equipment and (b) technical equipment might qualify as a technical specification.
conditions and characteristics of the plant necessary for Such a cell could be assumed to contain spilled or continued operation, as discussed below: uncontained solvent. If the temperature of the cell were allowed to rise to the flash point of the solvent, a fire a. Equipment and explosion might result which could adversely affect the confinement systems.
Several types of equipment are important to the safety of the operation and to the maintenance of a To derive a limiting condition for operation, barrier between the radioactivity inside the plant and the one must consider both the minimum complement of external environment. For these types, technical equipment necessary to maintain operation in the
"normal" range and the equipment neccessary specifications must establish the lowest acceptable level to of performance for a system or component and the accommodate abnormal situations. For example, minimum number of components or the minimum sufficient equipment in all systems should be operable so portion of the system that must be operable or available. that in the event of further, but limited and defined, failure of equipment. a power outage or other transient situation, or an error in operation, the plant could be One such type of equipment, with its associated safely shut down and the design basis accident could be specifications, consists of those systems and accommodated with the equipment remaining availabie.
components directly related to the control of operating conditions essential to safety and to the prevention of 3. Surveillance Requirements accidents. Many items in this type also will have safety limits. As examples, this type would include Major emphasis in surveillance specifications should concentration monitors, temperature monitors, be placed on those systems and components which are interlocks to control maximum evaporator temperatures, essential to safety during all modes of operation or are and radioactivity monitors on effluetts. necessary to prevent or mitigate the consequences of accidents. Tests, calibrations, or inspections are A second type is the vital equipment and necessary to verify performance and availability of services which must always be available or in a state of important equipment and detect incipient deficiencies.
3.6-4
and' technical posit,ons, for members of saiecy This is particularly true of those systems that are not committees when such exist. and for positions on the used for normal operation but are necessary to cope operating staff. For this purpose, a chart may be used, if with abnormal situations.
preferred, with footnotes as required.
Surveillance requirements and limiting conditions b. Administrative action to be taken by the licensee in the event any requirement imposed by for operation are frequently complementary. For a technical specifications is violated.
specific system, a limiting condition specification will c. Detailed written procedures governing normal typicaliy establish the minimum performance level, and the surveillance requirement will prescribe the frequency operation, abnormal situations, emergencies, and and scope of tests to demonstrate such performance. maintenance operations that may affect plant safety.
d. Logs and records of operation, maintenance.
changes to procedures and equipment, tests. inspections.
Surveillance requirements also include effluent calibrations, incidents, investigations, and reviews.
monitoring and site environmental monitoring. The e. Review and approval mechanisms for object of effluent and environmental monitoring is to authorization of new procedures as well as changes in verify and demonstrate that the integrity and procedures, equipment, and process, and for determining performance of the barners designed to contain whether such changes can be made within the existing radioactivity have been adequate to protect public technical specifications.
health and safety.
f. Training programs for plant personnel.
g. Periodic review and audit of operations, Whenever possible, the frequency and type of including performance of both equipment and operating surveillance should be based on quantitative data derived personnel.
through experience or experiment on the possible rate at h. Reports to the AEC.
which defects might occur or at which limits might be exceeded. Surveillance programs should be periodically V. CHANGES IN TECHNICAL SPECIFICATIONS
examined and modified as necessary to reflect new data AND IN PLANT EQUIPMENT
or conditions.
4. Design Features The technical specifications discussed in this guide are incorporated into the license issued for the operation.
These technical specifications cover design of a facility. This means that the limits and conditions characteristics of special importance to each of the set forth in the specifications become legal bounds physical barriers and to the maintenance of safety within which the licensee is required to operate the margins in the design. The principal objective of this facility.
category is to control changes in design of vital equipment. The system of specifications described above is intended to provide a reasonable degree of flexibility to Selection of specifications in this category should be licensee management for its control of operations in the predicated upon an examination of all, equipment and interest of safety. Furthermore, in recognition of the materials associated with (and including) each barrier fact that. as knowledge and experience accrue, changes with respect to: in specifications or in equipment may become desirable a. Whether a change in design would affect any or even necessary, the rules of the Commission provide technical specification; for two categories of changes:
b. Whether any margin of safety associated with I. Changes in technical specifications or changes any technical specifications wouid be affected; and that involve an "unreviewed safety question" (see c. Whether the equipment or its performance is § 50.59 of 10 CFR Part 50) require prior review and covered in any other technical specification. authorization by the Commission.
2. Certain changes in plant equipment and procedures may be made by the licensee without prior
5. Administrative Controls Commission authorization provided he is able to make a suitable finding to the effect that the change does not Tne Safety Analysis Report should contain a fuli involve an unreviewed safety question.
description and discussion of organization and
&dministrative systems and procedures for operation of As equipment and personnel performance data the facility. become available throughout the operating life of a facility, earlier studies and data should be regularly Technical specifications of tnis category should reconsidered and updated to reflect actual experience.
consist of summary statements and descriptions of ad mi*istrative arrangements for the Collowing subjects: When a change in a technical specification appears a. Organization ..ýhowing lines of authority from in order, its effect on related equipment and procedures top kilcensee) management on througli all activities, both should be analyzec and evaluate
d. The basis for the
"old" specification provides a starting point for technical and operationai, with a description of the minimnrum qualifications established for key management evaluation of the cnange.
3.6-5
When a chanie or a., s.t ts jodz1'...or. is. necessaay to justify the chanp, a revised basis should be contemplated, It ihiuld bo ititdffact on rxar.-tcf related equipment &no Iwocodurw, ,,. £'oy a4 tfkc: on provided, In addition, a revised bads should'be sub.
the validity of the balss for t14iot wr& 1wiual mitted whenever a determination is made that an exist.
specifcatiaons. In tids way, it C4,1 he deoer*nild whether lng one is not valid, regardlesa of whether a splclcaUtion the mapn of safety would be adversely sff'ecwd. Where chane isproposed.
CELL
BARRIER VESSEL GLOVE BOX BUILDING DISTANC
I I
I I
RELEASE RELEASE
FACILITY NORMAL AINORMA L ] TOCELL OR '
RELEASE
T
iOFF-MT
CONDITION OPERATION OPERATICd GLOVED TCONEOUENCES
-ENCLOSURE BUILDING IATMOSIOEREI
Il - -I ý I I
Figure 1. RELATIONS AMONG PHYSICAL BARRIERS AND FACILITY CONDITIONS
3.6-6
I Danger Zone Unacceptable consequences may occur.
SAFETY LIMIT
I Allowance for Uncertainty Damage or Consequences in Omet of LIMITING CONTROL SETTING
I Safety Margin Allowance for control or safety system action plus calibration uncertainties and instrument inaccuracies.
NORMAL OPERATING LIMIT
I Operating Margin Necessary to allow for instrument drift, minor operational errors, and fluctuations in process or control characteristics.
I Zone of Normal Operation Figure 2. LIMITS ON SAFETY PARAMETERS
3.6-7
EXHIBIT I
SUGGESTED FORMAT FOR TECHNICAL SPECIFICATIONS
Title (e.g., Temperature Control of Waste Evaporators)
Applicability. System(s) or portion(s) of the facility to which the specification applies should he clearly defined.
Objective. The reason(s) for the specification and the specific unsafe condition(s) it is intended to prevent.
Specification. Safetly limits and limiting control setting(s) for the important variable(s), or the condition or surveillance requirement imposed.
Bases. The Safety Analysis Report should contain all pertinent information and an explict, detailed analysis and assessment supporting the choice of the item and its specific value or characteristics. The basis for each specification should contain a summary of the information in the Safety Analysis Report in enough depth to indicate the completeness and validity of the source material and to provide justification for the specification. Subjects which may be appropriate for discussion in the bases are:
i. Technical Basis The technical basis is derived from technical knowledge of the process and its characteristics and should support the choice of the particular variable as well as the value of the variable. The results of computations, experiments, or judgments should be stated, and analysis and evaluation should be summarized.
2. Equipment A safety limit often is protected by or closely related to certain equipment. Such relation should be noted, and the means by which the variable is monitored and controlled should be briefly mentioned.
For specifications in categories 2, 3, and 4 of the text of this guide, this section of the bases is particularly important. The function of the equipment and how and why the requirement is selected should be noted here. In addition, the means by which surveillance is accomplished should be noted. If surveillance is required periodically, the basis for frequency of required action should be given.
3. Operation The margins, and the bases therefore, that relate to the safety limit(s), the operating limit(s),
and the normal operating zone(s) should be mentioned. The roles of operating procedures and of protective systems in guarding against exceeding a limit or condition should be stated. Brief discussion should be included of such factors as system response(s), process or operational transients, malfunctions, and procedural errors. Reference to related specifications should be made.
4. Assessment of Risk The degree of confidence in the value of the variable or the condition specified or the uncertainties associated therewith should be stated as precisely as is possible. The potential results and effects of exceeding the limit should be mentioned, and the risk resulting therefrom should be evaluated.
3.6-8