RS-16-196, Clinton - Updated Safety Analysis Report (Usar), Revision 18, Appendix a - Glossary
Text
CPS/USAR APPENDIX A A-i REV. 11, JANUARY 2005 APPENDIX A - GLOSSARY TABLE OF CONTENTS PAGE A.1 DEFINITIONS A-1 CPS/USAR APPENDIX A A-1 REV. 11, JANUARY 2005 APPENDIX A - GLOSSARY A.1 DEFINITIONS The following definitions apply to the terms used in the Clinton Power Station Updated Safety Analysis Report:
Abnormal Occurrence -- The occurrence of any station condition that: a. exceeds a limiting safety system setting as established in the technical specifications, or b. violates a limiting condition for operation as established in the technical specifications, or c. causes any abnormal operational transient, or
- d. causes any uncontrolled or unplanned release of radioactive material from the site. Abnormal Operational Transient -- Includes the events following a single equipment malfunction or a single operator error that is reasonably expected during the course of station operation. Power failures, pump trips, and rod withdrawal errors are typical of the single malfunctions or errors initiating the events in this category.
Accident -- A single event, not reasonably expected during the course of station operation, that has been hypothesized for analysis purposes or postulated from unlikely but possible situations, and that causes or threatens a rupture of a radioactive material barrier. A major pipe rupture qualifies as an accident; a fuel cladding defect does not.
Achieve Hot Shutdown -- The reactor is brought to hot shutdown through automatic action or manual control. Achieving Criticality -- (See also "Planned Operation") Includes all actions that are normally accomplished in bringing the reactor from a condition in which all control rods are fully inserted to a condition in which nuclear criticality is achieved and maintained.
Achieving Shutdown -- (See also "Planned Operation") Begins where "power operation" ends and includes all actions normally accomplished in achieving nuclear shutdown (i.e., reactor subcritical) following power operation. Activated Device - A mechanical module in a system used to accomplish an action; an activated device is controlled by an actuation device.
Active Component - A device characterized by an expected significant change of state or discernible mechanical motion in response to an imposed design-basis load demand upon the system; e.g., switch, relay, valve, pressure switch, turbine, transistor, motor, damper, pump, analog meter, etc. Active Failure - The failure of an active component to perform its function when called upon to do so by an initiating signal.
CPS/USAR APPENDIX A A-2 REV. 11, JANUARY 2005 Actuation Device - An electrical or electromechanical module controlled by an electrical decision output used to produce mechanical operation of one or more activated devices, thus achieving necessary action. Administrative Controls - (See also "Technical Specifications and Operational Requirements Manual (ORM)") The provisions relating to organization and management, procedures, record keeping, orders, instructions, policies, practices, designation of authority and responsibilities, review and audit, and reporting necessary to ensure operation of the facility in a safe manner. Anticipated Operational Occurrences - Those conditions of normal operation that are expected to occur one or more times during the life of the nuclear power unit and that include, but are not limited to, loss of power to a11 recirculation pumps, tripping of the turbine-generator set, isolation of the main condenser, and loss of all offsite power.
Auxiliary Building - A building adjacent to the containment building housing components of the emergency core cooling systems and other nuclear system-related equipment.
Availability - The probability that a device will be operable when called upon to perform its specified function.
Available Reactor Power - The rated power available for the turbine, 2897.5 MWt. Refers to rated reactor power adjusted for pump heating power pickup, cleanup demineralizer system power loss, and other system power losses.
Biological Shield - The reactor shield wall.
CFM - Cubic Feet of air per Minute. This is standard air unless otherwise stated. Standard air is air with a density of 0.075 lbs/cu.ft. This is substantially dry air at 70°F and a barometric pressure of 29.92" mercury. CFM for all HVAC systems is generally measured and converted to SCFM (Standard Cubic Feet Per Minute) with the exception of the VG (SGTS) which is measured in ACFM (Actual Cubic Feet Per Minute). Based on Industrial Ventilation, a manual of recommended practices, Section 9 (written by ACGIH (American Council of Governmental Hygienist), if the temperature of the air stream varies more than 30°F from the standard temperature, if the altitude is greater than 1,000 feet and/or the moisture content of the air is 0.02 lb/lb of dry air or greater, it is advisable to make a correction for density change.
Channel - An arrangement of one or more sensors and associated components used to evaluate station variables and produce discrete outputs used in logic. A channel terminates and loses its identity where individual channel outputs are combined in logic. Circulating-Water Screen House - A structure housing the traveling screens, circulating water pumps, plant service water pumps, shutdown service water pumps, fire water pumps, and necessary strainers.
Cold Shutdown Mode - The reactor is in the cold shutdown mode when the mode switch is in the shutdown position and the coolant is maintained at less than or equal to 200ºF. Common Station HVAC Vent - The release point (approximately 200 feet) for all potentially contaminated station ventilation exhaust air, excluding that air released via the Standby Gas Treatment System (SGTS) vents.
CPS/USAR APPENDIX A A-3 REV. 11, JANUARY 2005 Components - Items from which a system is assembled (such as resistors, capacitors, wires, connectors, transistors, switches, springs, pumps, valves, piping, heat exchangers, and vessels).
Containment Integrity - Refer to Technical Specification Bases B3.6 Containment Pool - (also called the "containment upper pool or upper containment pool) The pool of water, located directly above the reactor, providing radiation shielding during power operation and refueling. It consists of three distinct areas: (1) the reactor well, located directly above the reactor; (2) the containment fuel transfer, fuel, and dryer storage area; and (3) the steam separator storage area. The containment pool also provides makeup to the suppression
pool. Cooldown - (See also "Planned Operation") Begins where "achieving shutdown" ends and includes all actions normally accomplished in the continued removal of decay heat and the reduction of nuclear system temperature and pressure.
Core Alteration - Refer to Technical Specifications 1.1, Definitions.
Design Bases - That information which identifies the specific functions to be performed by a structure, system, or component of the facility, and the specific values or ranges of values chosen for controlling parameters as reference bounds for design. These values may be (1) restraints derived from generally accepted "state-of-the-art" practices for achieving functional goals, or (2) requirements derived from analysis (based on calculation and/or experiments) of the effects of a postulated accident for which a structure, system, or component must meet its functional goals. Design-Basis Accident - A hypothesized accident, the characteristics and consequences of which are utilized in the design of those systems and components pertinent to the preservation of radioactive material barriers and the restriction of radioactive material release from the barriers. The potential radiation exposures resulting from a design-basis accident are greater than those resulting from any similar accident postulated from the same general accident assumptions. For example, the consequences of a complete severance of recirculation loop line may be more severe than those resulting from any other pipeline failure inside the primary containment.
Design Documents - Documents such as drawings, standards, calculations, analysis, procedures, and specifications generated during or resulting from the design process that provide requirements for fabrication, construction, installation, or modification. Design Features - Portion of the plant Technical Specifications that discusses those features of the facility such as materials of construction and geometric arrangements, which, if altered or modified, would have a significant effect on safety and are not covered by a safety limit, limiting control, for operation, or by a surveillance requirement.
Design Power - This is the highest power level that would be permitted by plant design. Several design power levels were assumed in the analyses of CPS. The LOCA analysis and most of the initial cycle transient analyses were performed based on a power level of 3015 MWt which represents 104.2% of rated thermal power. The LOCA radiological consequences analysis was performed based on an initial power level of 3039 MWt representing 105% rated thermal power.
CPS/USAR APPENDIX A A-4 REV. 11, JANUARY 2005 The containment response analysis was performed at 2952 MWt which corresponds to 102%
rated thermal power. Diesel Generator Building - A building housing the diesel generators, the diesel fuel oil tanks, and the diesel generator HVAC equipment.
Drywell - (See also "Radioactive Material Barrier") A pressure containing envelope, surrounding the reactor and its recirculation loops, that channels steam resulting from a LOCA through the suppression pool for condensation. Engineered Safeguard/Engineered Safety Feature An engineered safety feature is a safety system, the actions of which are essential to a safety action required in response to accidents, that is provided to mitigate the consequences of postulated accidents.
Excursion - A sudden, very rapid rise in the reac tor power level above its safety limit. Fuel Building - A building adjacent to the containment housing new fuel, fuel handling equipment, and spent fuel storage. Functional Test - The manual operation or initiation of a system, subsystem, or component to verify that it functions as required by design.
Heatup - (See also "Planned Operation") Begins where "achieving criticality" ends and includes all actions that are normally accomplished in approaching nuclear system rated temperature and pressure by using nuclear power (reactor critical). Heatup extends through warmup and synchronization of the turbine-generator.
Hot Shutdown Mode - (See also "Planned Operation") The reactor is in the hot shutdown mode when the mode switch is in the shutdown position and the reactor coolant temperature is greater than 200° F.
Hot Standby Mode - The condition of the reactor when it is operating with coolant temperature greater than 212° F, system pressure less than 600 psig, and the mode switch in the startup position.
Incident - Any anticipated operational transient, accident, or special event not considered as part of planned operation.
Incident Detection Circuitry - Includes those trip systems which are used to sense the occurrence of an incident.
Leakage - The low rate of airflow into or out of the containment building; maximum leakage rates are specified.
Limiting Conditions for Operation - (See also "Technical Specifications") Limiting conditions for operation are the lowest functional capability or performance levels of equipment required for safe operation of the facility. When a limiting condition for operation is not met, the licensee shall shut down the reactor or follow any remedial action permitted by the technical specifications until the condition can be met. The licensee shall notify the Commission, review the matter, and record the results of the review, including the basis for corrective measures
taken.
CPS/USAR APPENDIX A A-5 REV. 11, JANUARY 2005 Limiting Safety System Settings - Limiting safety system settings for automatic protective devices related to those variables having significant safety functions. Where a limiting safety system setting is specified for a variable on which a safety limit has been placed, the setting shall be chosen so that automatic protective action will correct the most severe anticipated abnormal situation before a safety limit is exceeded. If, during operation, the automatic safety system does not function as required, the licensee shall take appropriate action, which may include shutting down the reactor. He shall notify the Commission, review the matter, and record the results of the review, including the basis for corrective measures taken.
Logic - That array of components which combines individual bistable output signals to produce decision outputs. Loss-of-Coolant Accidents - Those postulated accidents that result from the loss of reactor coolant at a rate in excess of the capability of the reactor coolant makeup system, from breaks in the reactor coolant pressure boundary, up to and including a break equivalent in size to the double-ended rupture of the largest pipe of the reactor coolant system.
Machine Shop - An area on the ground floor of the radwaste building for the general machine shop and maintenance facilities. Minimum Critical Power Ratio - Refer to Technical Specifications 1.1, Definitions.
Minor Load Changes - Load changes within the specified system response capability for step and ramp changes.
Module - Any assembly of interconnected components that constitutes an identifiable device, instrument, or piece of equipment.
Nonconformance - A deficiency in characteristic, documentation, or procedure which renders the quality of an item unacceptable or indeterminate. Examples of nonconformances include: physical defects, test failures, incorrect or inadequate documentation, or unauthorized deviations from prescribed processing, inspection, or test procedures. Normal Operation - Synonymous with "planned operation." Nuclear Power Unit - A nuclear power reactor and associated equipment necessary for electric power generation, including those structures, systems, and components required to provide reasonable assurance that the facility can be operated without undue risk to the health and safety of the public. Nuclear Safety Operational Analysis - A systematic identification of the requirements for and the limitations on station operation necessary to satisfy nuclear safety operational criteria.
Nuclear Safety Operational Criteria - A set of standards used to select nuclear safety operational requirements. Nuclear Safety System - A safety system, the actions of which are essential to a safety action required in response to an abnormal operational transient.
CPS/USAR APPENDIX A A-6 REV. 11, JANUARY 2005 Nuclear Steam Supply System (NSSS) - A contractual term which designates those components of the nuclear system and its related safeguards and instrumentation furnished by the nuclear steam supply system supplier (GE).
Nuclear System - Generally includes those systems most closely associated with the reactor vessel which are designed to contain or be in communication with the water and steam coming from or going to the reactor core. The nuclear system includes the following: a. reactor vessel, b. reactor assembly and internals,
- c. reactor core,
- d. main steamlines from the reactor vessel out to and including the outermost isolation valves outside the containment, e. neutron monitoring system,
- f. reactor recirculation system,
- g. control rod drive system,
- h. residual heat removal system,
- i. reactor core isolation cooling system, j. emergency core cooling systems, k. reactor water cleanup system,
- 1. feedwater system piping between the reactor vessel and the first valve outside the containment, and m. pressure relief system.
Nuclear System Process Barrier - (See "Reactor Coolant Pressure - Boundary") Occupational Dose - The dose received by an individual in the course of employment in which the individual's assigned duties involve exposure to radiation and/or radioactive material from licensed and unlicensed sources of radiation, whether in the possession of the licensee or other person. Occupational dose does not include doses received from background radiation, from any medical administration the individual has received, from voluntary participation in medical research programs, or as a member of the public.
Operable - A system or component is considered operable when it is capable of performing its required function in the required manner. This may be demonstrated by periodic testing.
Operating - A system or component is operating when it is performing its required action in the required manner.
CPS/USAR APPENDIX A A-7 REV. 11, JANUARY 2005 Operational - The adjective "operational," along with its noun and verb forms, is used to reference the working or functioning of the station, in contrast to the design of the station.
Operator Error - An active deviation from written operating procedures or nuclear station standard operating practices. A single operator error is the set of actions that is a direct consequence of a single erroneous decision. The set of actions is limited as follows: a. those actions that could be performed by only one person; b. those actions that would have constituted a correct procedure had the initial decision been correct; and c. those actions that are subsequent to the initial operator error and that affect the designed operation of the station, but are not necessarily directly related to operator error.
Passive Component -- A device characterized by an expected negligible change of state or negligible mechanical motion in response to an imposed design-basis load demand upon the system; e.g., cable, piping, valve in stationary position, resistor, capacitor, fluid filter, indicator lamp, cabinet, case, etc. Passive Failure -- Loss of function of a passive component. Place in Shutdown Condition -- Conduct an uninterrupted normal station shutdown operation until shutdown is attained and the mode switch is placed in the shutdown position.
Planned Operation -- Normal operations which are under planned conditions in the absence of significant abnormalities. Operations subsequent to an incident (transient, accident, or special event) are not considered planned operations until the procedures being followed or equipment being used are identical to those used during any one of the defined planned operations. The following planned operations are identified: a. refueling outage, b. achieving criticality,
- c. heatup,
- d. power operation,
- e. achieving shutdown, and
- f. cooldown. The planned operations can be considered as a chronological sequence: refueling outage -- achieving criticality -- heatup -- power operation -- achieving shutdown -- cooldown -- refueling
outage. Power Generation -- When used to modify such words as "objective," "design basis," "action," and "system," this term indicates that the objective, design basis, action, or system is related to the mission of the station, to generate electrical power, as opposed to concerns considered to CPS/USAR APPENDIX A A-8 REV. 11, JANUARY 2005 be of primary safety importance. Thus, the words "power generation" identify aspects of the station which are not considered to be of primary importance with respect to safety. Power Generation Action -- An action in the station which is essential to the avoidance of unacceptable results for power generation. There are power generation actions associated with planned operation, abnormal operational transients, accidents, and special events. Power Generation Design Basis -- States in functional terms, for a safety or power generation system, the unique design requirements which establish the limits within which the power generation objective shall be met.
Power Generation Evaluation -- Shows how the system satisfies some or all of the power generation design bases. Because power generation evaluations are not directly pertinent to public safety, they are generally not included. However, where a system or component has both safety and power generation objectives, a power generation evaluation can be used to clarify the safety versus power generation capabilities. Power Generation Objective -- A power generation objective describes in functional terms the purpose of a system or component as it relates to the mission of the station. This includes objectives which are specifically established so the station can fulfill the following purposes: a. the generation of electrical power through planned operation;
- b. the avoidance of conditions which would limit the ability of the station to generate electrical power; and c. the avoidance of conditions which would prevent or hinder the return to conditions permitting the use of the station to generate electrical power following an abnormal operational transient, accident, or special event. A system or piece of equipment has a power generation objective if it is a power generation system. A safety system can have a power generation objective, in addition to a safety objective, if parts of the system are intended to function for power generation purposes. Power Generation System -- Any system, the actions of which are not essential to a safety action, but are essential to a power generation action. Power generation systems are provided for any of the following purposes: a. to carry out the mission of the station--to generate electrical power--through planned operation; b. to avoid conditions which would limit the ability of the station to generate electrical power; and c. to facilitate and expedite the return to conditions permitting the use of the station to generate electrical power following an abnormal operational transient, accident, or special event.
Power Operation -- (See also "Planned Operation") Begins where "heatup" ends and includes continued operation of the station at power levels in excess of heatup power.
CPS/USAR APPENDIX A A-9 REV. 11, JANUARY 2005 Preoperational Test Program -- The preoperational test program applicable to the nuclear steam supply system (NSSS) is the test program conducted prior to fuel loading. The preoperational test program applicable to other station systems is the test program conducted prior to that system's required operation. Primary System Pressure Boundary -- (See "Reactor Coolant Pressure Boundary")
Procurement Documents -- Purchase requisitions, purchase orders, drawings, contracts, specifications, or instructions used to define requirements for purchase. This excludes documents of a purely commercial aspect; i.e., invoices, etc.
Protection System -- The electric and mechanical devices and circuitry (from sensors to actuation device input terminals) involved in generating those signals associated with the protective function. These signals include those that actuate reactor trip and that, in the event of a serious reactor accident, actuate engineered safety features.
Protective Action -- A protective action can be at the channel level or at the system level: a. A protective action at the channel level is the initiation of a signal by a single channel when the variable sensed exceeds a limit. b. A protective action at the system level is the initiation of the operation of a sufficient number of actuators, to effect a protective function.
Protective Function -- A protective function is the sensing of one or more variables associated with a particular generating station condition, signal processing, and the initiation and completion of the protective action at values of the variables established in the design bases.
Quality Assurance Manual (QAM) - Equivalent to the Quality Assurance Topical Report (QATR). Radiation - Any or all of the following: alpha particles, beta particles, gamma rays, X-rays, neutrons, high-speed protons, and other atomic particles; but not sound or radio waves or visible, infrared, or ultraviolet light.
Radioactive Material Barrier - Includes the systems, structures, or equipment that together physically prevent the uncontrolled release of radioactive materials. The barriers are the fuel cladding, the reactor coolant pressure boundary, and the containment.
Radioactive Material Barrier Damage - An unplanned, undesirable breach in a barrier. The operation of a relief or safety valve does not constitute barrier damage. Radiological Controlled Area - An area, access to which is limited to satisfy the requirements for personnel monitoring and/or need for contamination control.
Radwaste Building - A building housing all major components of the liquid, gaseous, and solid radwaste facilities; and shipping facilities, machine shop, and storerooms. Reactor Building - (See "Containment Building")
CPS/USAR APPENDIX A A-10 REV. 11, JANUARY 2005 Reactor Coolant Pressure Boundary (RCPB) - All those pressure containing components of boiling water-cooled nuclear power reactors, such as pressure vessels, piping, pumps, and valves, which are: a. part of the reactor coolant system; or b. connected to the reactor coolant system, up to and including any and all of the following: 1. the outermost containment isolation valve in system piping which penetrates containment, 2. the second of the two valves normally closed during normal reactor operation in system piping which does not penetrate containment, and 3. the reactor coolant system safety/relief valves. For nuclear power reactors of the direct-cycle boiling water type, the reactor coolant system extends to and includes the outermost containment isolation valve in the main steam and feedwater piping.
Reactor Coolant System - The vessels, pipes, pumps, tubes, valves, and similar process equipment that contain the steam, water, gases, and radioactive materials coming from, going to, or in communication with the reactor vessel.
Reactor Fuel Barrier - Uranium dioxide sealed in Zircaloy cladding. Reactor Isolated Condition - (i.e., all MSIVs closed) A condition wherein the reactor is isolated from the condenser.
Reactor Mode Switch - A multi-position switch that selects the appropriate sensors for scram functions and provides appropriate trip bypasses.
- a. Shutdown
- b. Startup
- c. Run d. Refuel Refueling Outage - (See also "Planned Operation") Includes all the planned operations associated with a normal refueling outage: a. planned, physical movement of core components (fuel, control rods, etc.);
- b. refueling test operations; and
- c. planned maintenance. For the purpose of designating frequency of testing and surveillance, a refueling outage shall mean a regularly scheduled refueling outage.
CPS/USAR APPENDIX A A-11 REV. 11, JANUARY 2005 Refuel Mode - Refer to Technical Specifications Table 1.1-1.
Reliability - The probability that an item will perform its specified function without failure for a specified time in a specified environment.
Repair - The process of restoring a nonconforming characteristic to a condition such that the capability of the item to function reliably and safely is unimpaired.
Restricted Area - An area, access to which is limited by the licensee for purpose of protecting individuals against undue risks from exposure to radiation and radioactive materials. There are no residential quarters in the restricted area.
Rework - The process by which a nonconforming item is made to conform to prior specified requirements by completion, remachining, reassembly, or other corrective means.
Run Mode - Refer to Technical Specifications Table 1.1-1. Sacrificial Shield - The reactor shield wall.
Safety - When used to modify such words as "objective," "design basis," "action," and "system," the word indicates that the objective, design basis, action, or system is related to concerns considered to be of nuclear safety significance, as opposed to the station mission-to generate electrical power. Thus, the word "safety" is used to identify aspects of the station which are considered to be of primary importance with respect to safety. A safety objective or safety design basis does not necessarily indicate that the system is an engineered safety feature.
Safety Action - An ultimate action in the station which is essential to avoiding specified conditions considered to be of primary safety significance. The specified conditions are those that are most directly related to the ultimate limits on the integrity of the radioactive material barriers or the release of radioactive material. These are safety actions associated with planned operation, abnormal operational transients, accidents, and special events. Safety actions include such actions as the indication to the operator of the values of certain process variables, reactor scram, emergency core cooling, and reactor shutdown from outside the control room.
Safety Design Basis - States in functional terms the unique design requirements that establish the limits within which the safety objective shall be met. A power generation system may have a safety design basis which states in functional terms the unique design requirements that ensure that neither planned operation nor operational failure by the system results in conditions for which station safety actions would be inadequate.
Safety Evaluation - Shows how the system satisfies the safety design basis. A safety evaluation is performed only for those systems having a safety design basis. Safety evaluations form the basis for the technical specifications and establish why specific safety limitations are imposed. Safety Limits - Safety limits are limits upon important process variables which are found to be necessary to reasonably protect the integrity of certain of the physical barriers which guard against the uncontrolled release of radioactivity. If any safety limit is exceeded, the reactor shall be shut down until the Commission authorizes resumption of operation.
Safety Related -- The term is defined to mean those structures, systems, and components necessary to meet any or all of the following:
CPS/USAR APPENDIX A A-12 REV. 11, JANUARY 2005 a. maintain the integrity of the reactor coolant pressure boundary, b. provide the capability to shut down the reactor and maintain it in a safe shutdown condition, or c. provide the capability to prevent or mitigate the consequences of accidents which could result in potential offsite exposures comparable to the guideline exposures of 10 CFR 100.
Safety System -- Any system, group of systems, component, or group of components, the actions of which are essential to accomplishing a safety action, such that unacceptable safety results are avoided.
Scram -- The automatic rapid insertion of control rods in response to the detection of undesirable conditions.
Sensor -- That part of a channel used to detect variations in a measured variable.
Setpoint -- That value of a monitored plant variable that results in a channel trip when the monitored variable reaches or exceeds this value.
Shutdown -- (also called "Subcritical") The reactor is shutdown when the effective multiplication factor (keff) is sufficiently less than 1.0 that the withdrawal of any one control rod cannot produce criticality under the most restrictive potential conditions of temperature, pressure, burnup, and fission product concentration.
Shutdown Mode - Refer to Technical Specifications Table 1.1-1. Single Failure - An occurrence which results in the loss of capability of a component to perform its intended safety functions. Multiple failures resulting from a single occurrence are considered to be a single failure. Fluid and electric systems are considered to be designed against an assumed single failure if neither (1) a single failure of any active component (assuming passive components function properly), nor (2) a single failure of any passive component (assuming active components function properly), results in a loss of the capability of the system to perform its safety functions. (Single failures of passive components in electrical systems should be assumed in designing against a single failure. The conditions under which a single failure of a passive component in a fluid system should be considered in designing the system against a single failure are under development by the NRC.)
Special Event - An event which qualifies neither as an abnormal operational transient nor as an accident, but which is postulated to demonstrate some special capability of the station or its systems. Startup Mode - Refer to Technical Specifications Table 1.1-1.
Startup Test Program - The startup test program applicable to the nuclear steam supply system (NSSS) includes those tests performed following initiation of fuel loading. The startup test program applicable to other station systems is the test program performed before that system's required operation.
CPS/USAR APPENDIX A A-13 REV. 11, JANUARY 2005 Station -The Clinton Power Station, which consists of one unit and all station facilities and property. Suppression Pool -- A pool of water, located inside the base of the containment building, which normally provides the water seal between the drywell and containment building. During safety relief valve discharge and postulated LOCA's, it serves as a heat sink to absorb decay heat and sensible heat from the reactor. The suppression pool also condenses steam from the reactor core isolation cooling system turbine exhaust. Surveillance Requirements -- Requirements relating to test, calibration, or inspection to ensure that the necessary quality of systems and components is maintained, that facility operation is within the safety limits, and that the limiting conditions of operation are met.
Test Duration -- The elapsed time between test initiation and test termination.
Test Interval -- The elapsed time between the initiation of identical tests.
Trip -- The change of state of a bistable device that represents the change from a normal condition. A trip signal, which results from a trip, is generated in the channels of a trip system and produces subsequent trips and trip signals throughout the system as directed by the logic. Trip Setpoint -- That value of a monitored plant variable that results in a channel trip when the monitored variable reaches this value.
Trip System - That portion of a system encompassing one or more channels, logic, and bistable devices used to produce signals to the actuation logic. A trip system terminates and loses its identity where outputs are combined in logic. Turbine Building - A building housing the main turbine, condenser, and generator and also including the feedwater heater bay, condensate demineralizers, and other related equipment.
Turbine Cycle Rated Power - Rated power available (2897.5 MWt) for the turbine. Unacceptable Results for Power Generation - Specified unacceptable conditions considered to be of primary significance and most directly related to the station objective.
Unacceptable Safety Results - The specified unacceptable conditions that are most directly related to the ultimate limits on the integrity of the radioactive material barriers or the release of radioactive material.
Unit - The unit consists of the nuclear steam supply system, turbine-generator, and supporting facilities.
Unrestricted Area - An area, access to which is neither limited nor controlled.