ML20010E527

to Design Criteria for Pipe Stress.

ML20010E527
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	07/14/1981
From:	Crain M, Hoffman J, Valler L EARTHQUAKE ENGINEERING SYSTEMS, INC., YANKEE ATOMIC ELECTRIC CO.
To:
Shared Package
ML20010E526	List: ML20010E525 ML20010E527 ML20010E528
References
DC-1, IEB-79-02, IEB-79-14, IEB-79-2, NUDOCS 8109040222
Download: ML20010E527 (7)

Text

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. .. Job No. 80005

. DC-1, Rev. 1

, July 14, 1981 3

} VERMONT YANKEE NUCLEAR POWER STATION i

l DESIGN CRITERIA l FOR PIPE STRESS i

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YANKEE ATOMIC EL11CTRIC COMPANY FRAMINGilAM, MASSACliUSETTS

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Prepared by: ( 7!/y,!j_

B Grouppleader Date Reviewed by: 3 f f/4/#/

pdepende viewer (YAEC) Date I

Approved by: &e Phb Project Engineer 7- N-F/

Date I

l Earthquake Engineering Systems,-Inc...

600 Atlantic Avenue .

8109040222 810926 Boston, Massachusetts 02210 PDR ADOCK 05000271 O PDR

. 1.0 SCOPE The purpose of this document is to provide 'echnical guide-lines to perform pipe stress re-analysis the Vermont Yankee Nuclear Power Station by Earthquake Engineering Systems, Inc., (EES) for Yankee Atomic Electric Company (YAEC). The systems that N111 require re-analysis shall be defined by the Project Engineer. Computerized piping stress analysis shall be done by nationally recognized, indepen-dently verified programs such as ADLPIPE (A.D. Little Co.),

PIPESD (J.A. Blume G Associates) or NUPIPE (Nuclear (Services).

2.0 CODES The following codes and standards shall be used in pipe stress analysis activities:

a) American Nationni Standard Institute Code for Power Piping - ANSI B31.1 1977 Edition, hereafter referred to as ANSI B31.1 b) American Society of Mechanical Engineers ASME Boiler and Pressure Vessel Code - Section III (1977 Winter Edition) c) Nuclear Regulatory Guideline 1.92 " Combining Modal Responses and Spatial Components in Seismic Response Analysis" d) American Society of Mechanical Engineers "ASME Boiler and Pressure Vessel Code,Section I G VIII, Division I; 1977 Winter Edition 3.0 REFERENCE DOCUMENTS The following reference documents shall be used in carrying out the pipe stress analysis activities:

a) Yankee Atomic Electric Company, " Final Safety Analysis Report, Vermont Yankee Nuclear Power Station" b) Vermont Yankee Insulation Specification VYNP-III-I-1 c) Vermont Yankee Piping Specification "BWR-QC10" d) Grinnel Pipe Hanger Catalog, PH-76 e) Vermont Yankee Nuclear Power Plant Flow Diagrams and Piping Drawings f) YAEC Stiffness Coupling Criteria (letter MEG 58/81, dated 2/11/81)

DESIGN CRITERIA 80005 DC- 1 VERMONT YANKEE NUCLEAR POWER STATION C== C==S YANKEE ATOMIC ELECTRIC COMPANY Rev. 1 Page 1 of 7

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4.0 DESIGN AND ENGINEERING /

4.1 Geometry Modeling:

The following considerations shall be made for geometry modeling.

Each problem shall be considered from anchor to anchor. 12 anchor to anchor exceeds program limitations, the following approach shall be considered in modeling:

Overlapping in such a way that there is negligible migration of loads from one problem to another.

Bracketing results of multiple computer runs to assess boundary conditions or loading conditions.

The geometry and restraint conditions shall be modeled in accordance with EES "As-Built" Isometrics.

The pipe material properties and analysis condition shall be considered as per YAEC's approved documentation such as the Vermont Yankee Piping Specification (BWR QC-10), YAEC flow diagrams, the Vermont Ytnkee Insulation Specification (VYNP-III-I-1) and Grinnel catalog data.

Branch lines will be considered coupled statically and dynamically to the main run pipe if the following require-ment is met:

a) Branch lines with a nominal diameter greater than 2 inches: Couple the systems if the ratio of moments of inertia (pipe / branch) is 25:1 or less b) Branch lines with a nominal diameter 2 inches and less:

Couple the systems if the ratio of moments of inertia (pipe / branch) is 10:1 or less ,

Equipment nozzles and penetrations shall be considered anchor points in the analysis. Loadings shall be summarized on EES Anchor Load Summary and Nozzle Load Summary forms and included in the Piping Analysis Summary calculction.

Valves shall be modeled as follows:

Thickness of the valve body shall be assumed as twice the connecting pipe wall thickness Diameter of the valve body shall be modeled as I times the matching pipe diameter DESIGN CRITERIA 80005 DC - 1 VERMONT YANKEE NUCLEAR POWER STATION Rev. 1 C==ES YANKEE ATOMIC ELECTRIC COMPANY Page 2 of 7

Manually operated valves and check valves shall be modeled with the mass of the valve concentrated at the centerline of the pipe midway between the valve inlet and outlet.

Motor and air operated valves shall be modeled as eccentric mass points. The total weight of the valve shall be concentrated at a point one-third (1/3) the distance between the cer erline of the pipe and cen-terline of the operator assembly (one-third of th " stem length" measurement as noted on the valve data form)

Body length of the valve shall be assumed as two (2) pipe diameters if not divisioned on the isometric drawing.

Seismic accelerations on the valves shall not be summarized.

As per ANSI B31.1 code requirements, bypass lines shall be assumed to be Schedule 80, and of a material of the same nominal chemical composition and physical properties as that used for the mainline, unless otherwise specified on YAEC flow dia; rams or the VYNP piping specification.

Fianges shall be considered as additional weights. Flange thickness shall be assumed to be the same thickness as the connected pipe for purposes of modeling stiffness.

Stress intensification factors for tees, reducers, flanges, elbows and conplings (half and full) shall be considered as per code requirements (ANSI B31.1) and all applicable ASME and manufacturer's published test data.

For the purpose of analysis, penetration snall be treated as follows:

Grouted pctetrations: A two-way restraint condition shall be assumed to exist on either side of.the penetra-tion for all load cases. Axial restraint of the pipe shall not be considered unless a welded collar is indi-cated on the pipe and embedded in tne penetration.

Ungrouted penetrations: At ungrouted penetrations, deflection of the pipe < h" shall be considered accep-table. Where deflections exceed " further review of ,

actual penetration clearances shall be initiated:

Deflections shall be based on the combined thermal and seismic conditions.

COPY DESIGN CRITERIA 80005 DC - 1 C""ES VERMONT YANKEE NUCLEAR POWER STATION YANKEE ATOMIC ELECTRIC COMPANY Rev. 1 Page 3 of 7

4.2 Dead Weight _ Analysis Dead weight analysis shall be perfarmed considering weight of the pipe, contcuts, insulation, concentrated nasses (other pipes supported off pipe, flange etc.).

Dead weight analysis stress results exceeding 1500 psi shall be brought to the attention of the P.E.

4.3 Thermal Analysis:

Thermal analysis of the piping system shall be performed based on maximum design temperatures as designated on YAEC flow diagrams. Overstresses due to thermal con-siderations shall be brought to the attention of the P.E. Subsequent therma) analysis may be initiated on a reduced temperature as directed / approved by YAEC.

Thermal anchor movements at nozzles and penetrations shall be indicated on the as-built isometrics and shall be based upon original Ebasco Design Isometrics as defined in Work Instruction 1.

4.4 Application of Spectra:

For each earthquake condition, three directions of carth-quake will be considered. (Two horizontal components and one vertical component). The total response due to each of

, the three (3) componci.ts of earthquake shall be calculated

first. These responses shall then be combined by the SRSS method (Square Root of the Sum of Squares). The procedures to be used in combining the modal responses and responses due to spatial components of earthquake shall be as fo11r.4s:

1. The modal responses for each component of earthquake shall be combined by taking into consideration the modes with closely spaced frequencies in accordance with NRC Regulatory Guide 1.92 Rev. 1, February 1976.

Subsections 1.2.1, 1.2.2, or 1.2.3.

2. The total systems responses due to the three (3) spatial components of earthquake are then combined by the SRSS method.

The responses of the Yankee site specific load case shall be used to evaluate the piping system and its support. For piping systems spanning several floors or with pipe supports connected to support structures attached to different floors, the response spectra for the analysis of the piping l system shall be the cnvelope of the floor response spectra

( of all the floors involved.

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DESIGN CRITERIA 80005 DC - 1 E[p==

]" VERMONT YANKEE NUCLEAR POWER STATION Rev. 1 YANKEE- ATOMIC-ELECTRIC COMPANY Page 4 of 7

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, Sustained Lcading Stress Evaluation The effects of pressure, deadload and other sustained mechan-inal loads shall satisfy:

fEo + .75i Ma < 1.0 Sh (Eq. 5.2) 4tn 1

Where:

P = internal design pressure, psig Do = outside diameter of pipe, inches tn = nominal wall thickness of component, inches Ma = resultant moment loading on cross section due to weight and other sustained loads, inch - Ibs Z = section modulus, inches 3 i = stress intensification factor. The product of .75i shall not be taken as less than 1.0.

Sh = basic material allowabic stress at maximum (hot) temperature; from ANSI B31.1 allowabic stress tabics 5.2 Occasional Loading Stress Evaluation The effects of pressure, weight, other sustained loads, and occasional loads including earthquake shall satisfy:

22o + .75i Ma + .75i Mb < kSh (Eq. 5.3) 4tn 1 1 Terms are the same as previously described, except:

k = 1.2 for evaluation of loading considering the OBE k = 1.8 for evaluation of loading considering the SSE Mb = resultant moment loading on the cross section due to carthquake inertia or.ly 5.3 Additive Stress (thermal) Evaluation The requirements of either equation 5.3(a) or 5.3(b) shall be satisfied:

i l COPY i

i DESIGN CRITERIA l

80005 DC - 1 VERMONT YANKEE NUCLEAR POWER STATION Rev. 1 YANKEE ATOMIC ELECTRIC COMPANY Page 6 of 7

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Thermal expansion alone -

Se = iM e 3 Sa Eq. 5.3(a)

Terms are as previously described, except:

Mc = range of resultant moments on the pipe cross section due to thermal expansion of the system and thermal anchor movements. Consider moment effects of earth-quake anchor displacements (SSE only) as full range and combine with thermal moments Sa = The allowable stress range for thermal expansion stresses, where:

Sa = f (1.25 Sc 4 0.25 Sh )

Sc = basic material allowable stress at system minimum (cold) temperature from the ANSI B31.1 Allowable Stress Tables Sh = as previously described f = stress range reduction factor for cyclic conditions.

(This will always be assumed as 1.0 for Vermont Yankee analysis)

Sustained Plus Thermal Expansion Stress -

P o + 0.75i Ma + i Mc I (Sh + Sa) (Eq. 5.3(b))

lDtn E E Terms are as previously described. Use only if Eq. 5.3(a) fails.

COPY I

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DESIGN CRITERIA l

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80005 DC - 1 VERMONT YANKEE NUCLEAR POWER STATION Rev. 1 YANKEE ATOMIC ELECTRIC. COMPANY-. -- -- ,

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