For the terms related to cement and concrete not de- fined herein, refer to ACI 116R. Terms listed in this Article have a specific meaning applicable to the Code.
anchor, concrete: a member, usually a steel rod with a
bend at one end or a headed bolt embedded in the con- crete, to which a liner, embedment, or surface‐mounted item is attached to prevent that item from pulling away from the hardened concrete.
auxiliary systems: features exclusively intended to control
or monitor conditions affecting structural integrity that augment the concrete containment (e.g., vessel cooling and insulation, corrosion protection systems, and stress– strain instrumentation).
bending stress: bending stress is the variable component
of normal stress; the variation may or may not be linear across the thickness.
bulk concrete temperature: the temperature of concrete
sufficiently remote from thermal or geometric discontinu- ities as to be representative of the generalized tempera- ture profile controlling overall structural response. Maximum values are established on the basis of accept- able material behavior for the load category under consideration.
channel: a circumferential recess or groove formed in the
external surface of a containment for the purpose of re- taining a circumferential prestressing system.
coating‐tendon: material used to protect against corrosion
or to lubricate the prestressing system.
component: a concrete containment that is governed by
the rules of this Division (NCA‐1210).
concrete placement: the deposition of concrete or the in-
gredients for concrete into forms or into members of a structure that serve as forms.
coupling: the means by which the prestressing force is
permanently transmitted from one portion of the pre- stressing steel to another to form a complete tendon.
ductility: the ratio of the maximum deformation or deflec-
tion of the member at the point of collapse to the maxi- mum elastic deformation or deflection at specified minimum yield in the member.
effective temperature at liner–concrete interface: the tem-
perature obtained by geometrically projecting the tem- perature gradient in the bulk of the concrete to the liner–concrete interface.
embedment: an item such as an anchor bolt, screed, or
conduit encased or partially encased in concrete. Reinfor- cing systems, liners, and structural members are not con- sidered embedments.
guaranteed ultimate tendon strength (GUTS): GUTS is the
lower of:
(a) the maximum tensioning force that can be applied
without breaking more than 2% of the tendon tension members and that can be guaranteed for all tendons
(b) the minimum guaranteed wire, strand, or bar
strength times the number of tendon wires, strands, or bars based on test conditions of 70°F (21°C), static loads, and unirradiated samples
leak‐chase channel: a channel section permanently in-
stalled over a liner weld to permit leak testing of the weld.
leak‐tight integrity: the ability of a component to maintain
a prescribed maximum leakage rate under all service conditions.
liner: a permanent metal membrane attached to the sur-
face of a concrete containment or penetration in order to form a leak‐tight enclosure.
liner attachment: member or component welded to either
the front or back surface of the liner plate, but not pene- trating the liner, such as lugs, brackets, anchors, and leak chase channels.
local hot spots: the maximum local temperature at the
liner in any part of the primary coolant due to either dis- continuity in the thermal barrier and liner cooling system, or to attachments on the coolant side of the liner which
penetrate the thermal barrier or at other locations within the bulk concrete due to radiation heating or other causes. It also includes liner areas subjected to high tem- perature jet impingement.
membrane stress20: the component of normal stress, hoop or meridional, that is uniformly distributed and equal to the average of stress across the thickness of the section under consideration.
mineral admixture (fly ash and pozzolans): a siliceous or
siliceous and aluminous material, which in itself pos- sesses little or no cementitious value but will, in finely di- vided form and in the presence of moisture, chemically react with calcium hydroxide at ordinary temperatures to form compounds possessing cementitious properties.
operating basis earthquake: for a site, that which produces
the vibratory ground motion for which those features of the power plant necessary for continued operation with- out undue risk to the health and safety of the public are designed to remain functional. The maximum vibratory ground acceleration of the operating basis earthquake is equal to at least one‐half that of the safe shutdown earthquake.
operating basis wind: wind velocities and forces required
for the design of a structure in accordance with the uni- form building code.
peak stress: total stress due to local discontinuities or lo-
cal thermal stress including the effects of stress concen- trations. Its basic characteristic is that it does not cause any noticeable distortion and is objectionable only as a possible source of a fatigue crack or brittle fracture or a localized concrete crack. A stress that is not highly loca- lized falls into this category if it is of a type that cannot cause noticeable distortion. Examples are stresses at a lo- cal discontinuity and thermal stresses produced by a local hot spot.
point stress: the maximum apparent stress calculated by
adding the membrane stress and the maximum bending stress calculated by elemental beam equations. When
advanced analytical methods (e.g., finite element analy- sis) are used for design, the point stress is defined as t h e m a x i m u m s t r e s s a c r o s s t h e s e c t i o n u n d e r consideration.
primary stress: any normal stress or a shear stress devel-
oped by an imposed loading that is necessary to satisfy the laws of equilibrium of external and internal forces and moments. The basic characteristic of a primary stress is that it is not self‐limiting. Primary stresses that consid- erably exceed the yield strength in a steel member or gross cracking in concrete will result in failure or in gross distortion. A thermal stress is not classified as a primary stress. Examples are stresses due to internal pressure or to distributed live loads and bending stress in the central portion of a flat slab due to pressure.
safe shutdown earthquake: for a site, that which produces
the vibratory ground motion for which those features of the power plant necessary to shut down the reactor and maintain the plant in a safe condition without undue risk to the health and safety of the public are designed to re- main functional.
secondary stress: a normal stress or shear stress devel-
oped by the constraint of adjacent material or by self‐ constraint of the structure. Its basic characteristic is that it is self‐limiting. Local yielding, minor distortions, and concrete cracking can satisfy the conditions that cause the stress to occur, and failure is not to be expected. Ex- amples are general thermal stresses, bending stress at a gross structural discontinuity, and stresses induced by concrete shrinkage and creep.
shear connectors: general term for steel members at-
tached to the liner and embedded in the concrete to pro- vide general compatibility of strains between liner and concrete.
structural integrity: the ability of a structure or compo-
nent to withstand prescribed loads.
tendon: the complete assembly consisting of pre‐stressing
steel and anchorages, and couplings. The tendons impart prestressing forces to the concrete.