ML19321A539

Earthquake Intensity for Piping Analysis & Pipe Support Design. FSAR Excerpt Encl

ML19321A539
Person / Time
Site:	Crystal River
Issue date:	10/11/1979
From:	Ferrarello S FLORIDA POWER CORP.
To:
Shared Package
ML19321A532	List: ML19321A531 ML19321A539
References
NUDOCS 8007230573
Download: ML19321A539 (9)

Text

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ATTACHMENT A FIDRIDA PCKER CDITOPATICN CESTAL RIVER UNIT 3 l

N DIITNSI'IY FOR PIPD1G ANALYSIS AND PIPE SUPPORT DESICJ 4

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10-11-79 e

413 9007230

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v BACMGRCIED

Sc ' earthquake intensities are normally associated with the design of Nuclear Power Plants. These are the Operating Basis Earthquake (OBE) and the Safe Shutdown Earthquake -(SSE). A nuclear power plant is

-expected to be designed so that a plant can continue to operate during an OE~ and to.be safely shutdown in the event of a SSE. 'Ihe ASME Boiler and Pressure Vessel (Section III, Subsections NA,ts,tC,ND,tE and NF)

Code lists specific' stress limits for pipe and supports for earthquake

and other loadings.

It is noted that the OBE stresses are restricted to lower allowabics than the SSE stresses.

. Many of the Crystal River Unit' 3 Design and Analysis activities were conducted during 1970.to 1974. At that time the method of dealing with the'tm' earthquake intensities was not as clear as it is today. The Crystal River Unit.3 FSAR attenpted to Provide guidance. For example, Section 5.2.1.2.9 " Earthquake Ioad" (A.tachnent 1) states the position as concerns the Structural Design of the Beactor Building. This descrip-tion is also applicable to the ccmnitment for pipe support design and analysis. Basically this conmitment is that the pipe and support stres-ses would be kept to within Code (USAS (AMSI) B31.1) Allowable Stresses.

The factors of-safety in the code allovables (Factor of Safety of 4) would then ensure that the pipe and pipe supports muld not be inpaired l

so as to present a safe and orderly shutdown of the plant in the event that the higher earthquake intensity muld occur (SSE).

-PIPE STRESSES Section 5.4.4 of the FSAR (Attachment. 2), " Piping Design Criteria" provides specific ccamit:nents in the area of piping design. Pages 5-64a and 5-64b state that the higher earthquake intensity (SSE or Maximum Hypothetical Earthquake (12IE) as known for Crystal River) is required to reet the USAS B31.1 Code. This is a nore stringent conmit:nent than that inplied earlier in the FSAR (Attachment.1). This more stringent e mmit=ent on pipe stress was a soluntary step, taken to add nore conservatisn to the-design.

!IJ3 ADS ON PIPE SUPPORTS Section 5.'4.4 ~(Attachment 2) of the FSAR did not-address the design loads on pipe suprorts. to alternatives existed here. These were:

i

1).Use OBE loads to ctrnpare against USAS B31.1 or AISC allowables

-(consistent with philosophy expressed in Attachnent 1).

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'2) Use MHE (or SSE) loads to' conpare against USAS =B31.1 or AISC i

. allowables1(consistent with voluntary cannitnent on pipe stress).

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s Since to FSAR comnit2nent on loads had been made, the firs't alterna-tive was selected as a reasonable design basis. Ibwever, all pipe supports were checked against criteria "2" for record purposes.

. Approx.imately 95% of all seismic category I supports neet USAS B31.1

' limits for the worst earthquake intensity (SSE or ME) while 5% meet USAS B31.1 limits only for the lo'Ar earthquake (CBE).

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It is predicted tisat maximum penetration depth for the vorst probable missile

-is 6.2 inches against the exterior concrete vall thickness of safety related structures which is 24 in. minimum. As such, it it concluded that secondary missiles vill not be generated within the structure which could damage the G

safety related equipment and systems.

In the Reactor Building, the personnel access, equipment access doors, and all penetrations are located inside Class I structures, which are ' designed for tornado generated missiles.

All access ' openlags in Auxiliary, Intermediate, Diesel Generator, and Control 13ullding are so located or protected by a missile shield so that no damage vill be done to cafety related equipment from tornado generated missiles.

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5.2.1.2 7 External Pressure The Reactor Building has been designed for an external atmospheric pressure of 2.5 pai Creater than that of the internal pressure that could be caused by an accidental diccharde from the spray system.

5.2.1.2.6 Operating Temperature The normal operating temperature profile is shown in Figure 5-11.

This profile obtained from Reference 28, for a nuclear generating station located. in va

!!arthern U.:1. A., which ha.: a raore severe vinter climate than Crystal River Unit 3.

Thu.; the uce of these proriles for Crystal River is considered to be conservative.

5.2.1.2 9 Earthquake Load The site seismoloc.' and response spectra are described in Section 2.

The seismic, design. of the Reactor. Building is based on the response to a ground c.cceleration as described beicv.

a.

Primary steady state stresses, when combined with the seismic stress rea.ultind frcm the response to a ground acceleration of 0.05c actind horinuntally and 0.033e acting vertically and occurrinc cimultanvuualy have been s.aintained witnin the allowable workinc.:trecc 11mitu uccepted as good practice and, where applicable, Oct forth in the appropriate desica standards, e.c: ASIS Boiler '

j nr.d Preccure Vecsel Code,(3) ACI 318-c3(b ), AISC Specification for the

]

Eucien and Erection or Structural Steel. for Buildings,l5) and USAS

(&::) 6 31.1(0) -

l b.

Primary steady state stress when combined with the seismic stress resulting frem the recpcnse to a ground acceleration of 0.10g acting l

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horiscntally. and 0.0GTc acting vertically and occurring simultaneously, has been limited so inat the functicn of the structure is not impaired su as to prevent, a safe and orderly shutdoun of the plant.

The respective vertical and horizontal seismic components,- at any point

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on the sl.cil, have been added by su: ming the absolute values of the response (i.e., stieca,. shear, ::ccent, or deflection) of each centributing frequency due t to vertict.1 rgtivn to the corresponding absolute valucu of the respense

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'of each cuatributind -frequency due to horizontal mation..

pg, 4-l -

5-12:

Am. 29 (8-15-73)

ATTACHMENT 2 SAC c.

Diesel Generator Building I'

d.

USSU Intake Pump Structure e.

Intermediate Building The tornado design requirements are as described in Section 5.2.1.2.6.

The structural design is in accordance with ACI 318-63, " Ultimate Strength Lesign."

5.4.3.2.3 Turbine Repcrt A vulnerability analysis of the plant design was made to determine what chhnges would have to be made in the event a turbine-n.issile could be produ:ed. The basic criteria for this analysis was that plant shutdown and securement could not be jeopardiced by a turbine-missile strike; merecver, the consequences cf a strike could not cause or result in an uncentrciled release cr excessive amcunts of radicactivity. Cn this basis, these systens, structures, and ccmponents required to perform this function ere reviewed, analyce ; for vulnerability, and where necessary changes were made.

5.h.L

_ FIPIDG DESIO" CRITERIA.

The piping design criteria for the primary locp is discusced in Section b.

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The follcuing design eriteria ecvers the pipe lines not described in Section L.

Duclear class piping systems have been fabricated, erected, and inspected with the i

intent of sc:isfying the hpplicable secticns Of the COLE FOR "UCLEAR PO',iER PIPING USAS (AUS) h31.7.

The basic guideline fer the design of piping has been the CODE FOR PRESSURE PIPING USAS ( A"S) LJ1.1.0-19c7 and thcse pcrtiens of COLE Case U7 Pertinent sections frcm this COLE apply to Class I piping described hereafter:

COLE Paru. 101.5.3 Earthquake "The effect of earthquakes, where applicable, shall be considered in the Jesign of piping, pipir.g supports, and restraints, using cata Ivr ti.e site as a guice in a::essing the forces involved.

!!cuever, earu. quakes need not te cen:idered as acting concurrently

vith vind."

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CODE Pira.101.5.k Vibration

" Piping shall be arranged and supported with consideration of vibration."

CODE ' Para.121.2.5 Svay Braces "Svay braces or vibration dampeners shall be used to control the

=ovement of piping due te vibration."

CODE Para.102.3.2 (d) Additive Stresses "The sus of the icngitudinal stresses due to pressure, veight, and other sustained loads shall not exceed the allevable stress in the het conditien S. Where the sus of these stresses is less than Sh, h

the difference between Sh and this sus may be added to the ter=

0.25 S3 in For=ula (1) for deter =ining the allevable stress range S."

A SA = f (1.25 S + 0.25 S )

(For=ula 1) e h

wh'ere Se = Basic material allevable stress at =inimu= (cold) te=perature frc= the Allevable Stress Table.

Sh = Easic material allevable stress at =sxi=us (hot) te=perature frc= the Allevable Stress Tables.

f = Stress range reduction facter for cyclic conditions for total nu=ber !! cf full temperature cycles over total nu=ber of years during which system is expected to be in operation.

The longitudinal pressure stress S13 was deter =ined by dividing the end force due to internal pressure by the cross-sectional area of the pipe vall:

2 F

Pd S

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1p.

A (L; _ d )

2 where S

=

longitudinal precsure stress, psi y

P

=

internal design pressure, psi d

=

nc=inal inside dia of the pipe, in.

D

= nc=inal cutside dia of the pipe, in.

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CODE Para.102.3.3 ramits of Calculated Stresses Due to occasional Loads j

"Tne sum of the icngitudinal stresses produced by internal pressure, liv,e'and dead loads and.those produced by occasional loads such as the temporary supporting'of extra vei6ht may exceed the allevable stress. values'given in the A11cuable Stress Tables by the amounts and duraticus of time given in Para.102.2.h."

CODE Para. 102.2.4 Allowance for Variations from Normal Operaticn

'"It is recognized that variations in pressure and temperature inevitably c: cur, und therefore the piping system shall be considered safe for cceacional operatica fo~ short periods at hi her than the design pressure E

or temperature.

Eithdr pressure or temperature, or' both, may exceed the design values' if the stress in the pipe vall calculated by 'the formulas using the nsxinu: extected prescure during the variation does not exceed the C-value allovable for the maximum expe 'ed temperature during the variation-by more than the folleving al.cvances for the periods of durati:n indi:ated:

(1) b'; to it percent increase abcee the S-value during 10 percent cf the operatind pericd.

(2) Up t-33 percent increase abcvc the S-value during i p d :n cf tl.c :.perat ing period "

f Major portienc...'las:

3 ping systems as herela described have been checked by the rmal, dynini r - ( r.

1:::c ), deadicad, and pressure strecc analysic.

For those pipe line: de:1gned in cc:ctdcm:e with the setemic design :riteria, dynamic analyses have been perfcr e1 as' herein described' giving due at tcut i:n to designed supports and rettraint:. Pipe line; cpernt:ng at elevated t emporutures nave been analyzed for

.ther:21 expans.cn :tre::es In adliticn, recog:.itica has been given to stresses produced by ir.ternal prcssure and the dead weight load of piping.

Class I pipin6 2-1/E" and larger (norns11y snop fabricated) along with piping system cem;,cnents in:luding cr.ubcers and d mpers are analy ed by the Engineer snd all support:,. res trair.t and piping system ec=penents are shown and located on the drawings. Any : hangec in Lt.e: field c.the locottens 23 shown en the drawings are to be cade cul: 2fter analycle and appr: val of the End neer. Class I piping i

le;; thin 2-1/e" (n:rr.aaiy field runi to installed in the fieltl in accordance

' tc the maxir.un cupp::,r*. u. i an: hor. :iteria ect ablishc3 by the Engineer. Tne crximum. sp2:inc : rivs with the ' 11n.: s ce and is der.ern.tned for the most severe scistic icading for the plant iccat:en.

All; pipir.;'two in, n r.inal pipe ti:e sad smai.er is e:nsidered to be " field run,"

i.e.,

it is fie'.1 fabricated fr : anditer.atened tsemetric drawings prepared by the Engineer.

.~he-iccee rt: drwuing slice; the apprcx mste r:uting cf the pipe.

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9 Typical pipe hanger sketches for these piping acccmblies vill be revi'eved and l

approved by.the I:ngineer for application and loading requirements prior to the

. sketches'being issued for fabrication. Significant variation in routing is not usually possible, as the piping must pass through wall and partition sleeves which are located and uniquely designated by the Engineer.

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Our_ mechanical contractor vill make " Field Fabrication Sheets" for these pipe ass mblies, which vill specify the following:

a.

A lict of required materials, together with heat numbers

,b.

The detail sketch of how to fabricate the assembly c.

The velding instructions d.

The velding record e.

The llCT and visual inspection records f.

The quality control inspections and sign-offs This will.all be in strict accordance with approved Field Work and Quality Control Procedures. This field fabrication cheet will then be issued to the field fabrication shop for fabt ication of the assembly.

All field required quality qcntrol measurec will be rigidly adhered to during this entire process. After.

installation.ur ti.e.ae acccmblies, an incpector vill "valk out" the particular accenbly and then cirn the associated field fabrication sheet as being "as-built",

or make ar.y nec :ccary revisionc to match the "as-built" c:ndition. Thus, the ori'ninal field rabrication chect will become the "a::-built" drawing of the assembly

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cheving th0 fic1d.run piping locations and constructicn details.

The perfornance tectc to be conducted on systems, cec.ponents, etc. after the if installation la ecnplete Will include hydrostatic / leak, electrical and instrumen-tation pre-operational in accordance with written and approved procedures.

In ad lition, cyutem and components vill be flunhed and cleaned to satisfy the level of cleanliness outlined in the Cleaning Requirement Document.

The combined primary ctressec ' produced by the mqimum.))ypothetical earthquake are a tintained at le::s than cr equal to '120 percent of the ecdc allovable stresses from AM01 B31.1-0-1967, plus code case N-7 for durations up to cne percent of the operating period.

As requir al by A:13I B31.7, Paragraph 1-701.5.h, piping systems vill be observed during startup and initial operation by qualified personnel to ascertain that these cystems are properly sup;)orted an.1/or rectrained to ensure that piping vibration is not excescive. kTnere, in the opinien of the qualified individual,. conditions exist detrimental to reliable operation corrective action vill be taken, e.g,

' additions' or-modifientions of cupport or restraints.

In the event that the vibration is. unacceptable and where an additional support does not correct an,

undesirabls condition

.'r cannot bc. provided, data vi31 be recorded at points of r.aximui.ibratien. Thic data' vill then-be used as input for analytical evaluation to correct the condition.

Also, durine ryst.em heatup in the hot func$.onal tests the piping vill be observed' for the.following:

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1.

Assure that hangers, supports and seismic restraints do not interfere with piping expansion.

2.

Assure that piping expansion does not interfere with equipment or other structures.

In addition, at pre-detennined points, markers shall be attached to the pipe and referenced to fixed points on the building structure or fixed extensions of the building structure. Such selected points sha21 be observed and the thermal movements recorded and compared with those predicted.

Operational tests performed to verify piping designs will consist of starting and stopping makeup and purification pumps, reactor coolant pumps. Decay heat pu=ps exercise of high pressure injection valves, and operation of the pressurizer relief valves.

The results of these various analyses have been compared with allowable stress values for the various conditions and are as follows:

(1) i Primary stresses for operation during the maximum hypothetical j

! earthquake (0.10g horizontal ground acceleration) did not exceed l 1.2 x Sh (CODE Tables A-1 & A-2 plus Code Case N-7).

(2) Thermal stresses did not exceed S as defined by CODE paragraph 102.3.2.

3 (3) Pressure stresses vere calculated in accordance with CODE paragraph 102.3.2.

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