ML19309C561

App 5A to TMI-1 PSAR, Structural Design Bases. Includes Revisions 1-11

ML19309C561
Person / Time
Site:	Three Mile Island
Issue date:	05/01/1967
From:	JERSEY CENTRAL POWER & LIGHT CO., METROPOLITAN EDISON CO.
To:
References
NUDOCS 8004080787
Download: ML19309C561 (5)

Text

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APPEICIX 5A STRUCTURAL DESIGH 3ASES O

v AEC Publication TD-7024, " Nuclear Reactors and Earthquake," as a=plified herein vill be used as the basic design for seismic analysis.

Structural design for nor=al operating conditions vill be governed by the applic".ble design codes. The design for the loss-of-coolant accident and

=axist f.s=ic condition vill ensure no loss of functions when related to public safety.

1 CLASSES OF STRUCTURES AND SYSTIM The plant structures, cc=ponents, and syste=s will be classified according to their function and the degree of integrity required to protect the public.

The classes are:

1.1 CLASS I These structures, cc=ponents, and systems, including instruments and centrols, whose failure =ight cause or increase the severity of a loss-of-coolant acci-dent or result in an uncontrolled release of excessive escunts of radicactivit-and those structures and ec=penents which are vital to safe shutdown and isolation of the reactor are classified Class I. W en a syste= as a whole is referred to as Class I, certain less essential portions not associated with less of function of the syste= =ay later be designated under Class II or III as appropriate. Examples of Class I structures, cc=ponents, and systems are:

O- a. Reactor Building and its penetrations including plant. vent.

b. Reactor Building crane.

c. Reactor vessel and its internals including control rod drive assemblies.

d. Vital ecoling water systems.

e. Pri=ary system including vents and drains within Reactor Building.

f. Spent fuel ecoliag syste= and shutdevn cooling system.

g. Makeup and purification system.

h. En61neered safeguards systems including their electrical power scurces and distribution systems.

i. Fuel stcrage pool.

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J. Reactor control rocs and equipment.

k. Waste disposal syste=.

1. Post-incident filtration syste=.

1.2 C1 ASS I!

Those structures, cc=ponents, and systems which are i=portant to reactor operation but not essential to safe shutdown and isolation of the reactor and whose failure could not result in the release of substantial a=ounts of radioactivity are classified Class II. Examples of Class II structures, components, and systems are:

a. Secondary coolant system.

b. Electric power system, except emergency syste=s.

c. Auxiliary building, and waste disposal building, except as included in Class I above.

1.3 CLASS III Those structures, co=ponents, and systems which are not related to reactor operation or containment are classified Class III.

2 CLASS I DESIGN 3ASES All structures, components, and systems classified as Class I vill be desi6ned in accordance with the following criteria:

a. Primary steady state stresses, when ecmbined with the seismic stress resulting from the response to a ground acceleration of 0.C6 6 acting horizontally and 0.0h g acting vertically and occurring simultaneously shall be maintained within the allowable working stress limits accepted as good practice and, where applicable, set forth in the appropriate design standards, e.g., ASME Boiler and Pressure Vessel Code, ASA 331.1 Code for Pressure Piping, Building Code Requirements for Reinforced Concrete, ACI 318 and AISC Specifications for the Design and Erection of Structural Steel for Buildings.

b. Pri=ary steady state stress when ecmbined with the seismic stress resulting from the response to a ground acceleration of 0.12 g acting horizontally and 0.08 g acting vertically and occurring 2 simultaneously, shall be li=1ted so that the function of the co=-

ponent, system, or structure shall not be impaired as to prevent a safe and orderly shutdown of the plant.

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. i 5A-2 (Revised 10-2-67)

3 CLASS II DESIGN BASES O All structures, components , and systems classified as Class II vill be designet for a ground acceleration of 0.06 g in accordance with procedures of the Unife Building Code.

k CLASS III DESIGH BASES All structures , ccuponents , and systems classified as Class III vill be designe in accordance with applicable building code requirements.

5 DAMPING FACTORS The folleving gives the damping factors used in the seismic design of component and structures.

Per Cent of Ccnconent 02 Structure Critical Damuing

1. Reactor Building 2.0

2. Concrete Support structures inside the Reactor Building 2.0

3. Assemblies and Structures a) Bolted or Riveted 2.5 b) Welded 1.0

h. Vital Piping Systens 0.5 5 Other Concrete Structures above ground 5.0 6 METHOD OF ANALYSIS The acceleration response spectra included in Appendix 23 vill be used for the design of Class I and II structures , ccuponents , and systems. The vertica' cc=ponent of ground motion is assumed to be 2/3 of the horizontal ccuponent.

The vertical and horizontal components are assumed to occur simultaneously anc their effects added algebraically.

For Class I structures, ecmponents , and systems the method of enalysis will either be a =odal analysis wherein modal shapes , frequencies , stresses , and proportionality factors are detemined or vill be perfomed as follows:

a. The natural period of vibration of the structure, ccaponent, or syste vill be detemined.

b. The response acceleration of the ecmponent to the seismic motion vil:

be taken frcm the response spectrum curve at the appropriate natural period, h4 ,

0002 357 5A-3

c. Stresses and deflections resulting from the ecmbined influence of normal loads and the additional load frcm the 0.06 g earthquake vill te calculeted and checked aEainst the limits i= posed by the design standard or code.

d. Stresses and deflections resulting frem the ccebined influence of the normal loads and the additional loads frem the 0.12 6 earthquake vill be calculated and checked to verify that deflections do not preveni.

functioning and that stresses do not produce rupture or excessive distortion.

e. The dynamic analysis of critical piping systems (i.e. . Class I systems )

vill'be a modal analysis based upon either a distributed or lumted-mass solution depending upon the complexity of the system. The two arproacnes are performed as follows :

1. Distributed-Mass Analysis

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L The system is renresented by a number of straight uniform beams with a distributed mass and stiffness. First, the transfer matrix for each of the straight beams is deter =ined and the rotation trans-fer matrix for each . joint calculated. Next the enuation of motion

{ is written in matrix form. Previously determined transfer matrices l are used. Considering the acpropriate boundary conditions. the characteristic determinant is generated. When the natural frequen-cies are known. the corresponding mode shapes are determined. Then.

l by using the response spectrum for a single-degree-of-freedom system, the maximum displacements are obtained as the root-mean-square sum of the modal maxim a. Finally, after the maximum displac ments are kncvn, forces and moments are calculated at the structural

.ioints.

2. Lumped-Mass Analysis The system is represented by a series of cencentrated masses. First the scace coordinates are established for the system and enordinates are established for the system and coordinates of = ass coints are determined. Using a static analysis, flexibility matrices corres-ponding to these mass points are commuted. Next, the ecuations of i

motion isare method written in matrix form. Force influence coefficients used.

assuming harmonic Natural motionfrecuencies and mode shaces are obtained of the system.

i Finally, using -he same tee

! nique as for the distributed-mass analysis, maximum internal forces and moments are calculated at the structural joints.

In additien to the earthquake response for the pipe system, the moda described above vill be used to determine forces and moments with resulting stresses for any transient or termanent displacements whic vill be induced at the suprort peints.

T RIFERESCES a., Nuclear Feactors and Earthauakes. AEC Publication TID ~iO24 0002 358 9 b.

Wind No. 3269.Forces on Structures. Task Cocm:ittee on vind fems. ASCE Pacer ~

..- 5A k (Bevised 1-8-68)