ML19257C054
| ML19257C054 | |
| Person / Time | |
|---|---|
| Site: | Perkins, Cherokee  |
| Issue date: | 12/31/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Dail L DUKE POWER CO. |
| References | |
| NUDOCS 8001240042 | |
| Download: ML19257C054 (2) | |
Text
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UNITED STATES
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8 NUCLEAR REGULATORY COMMISSION A
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101 MARIETTA ST., N.W., SUITE 3100
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ATLANTA, GEORGIA 30303 In Reply Refer To:
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50-488, 50-489 Duke Power Company Attn:
L. C. Dail, Vice President Design Engineering Post Office Box 33189 Charlotte, North Carolina 28242 Gentlemen:
The enclosed IE Information Notice No. 79-36 provides information on a computer code defect which can result in incorrect stress values for piping elbows.
Sincerely,
~ Y.~(
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JamesP.O'ReilIf_
Director
Enclosures:
I.
IE Information Notice No. 79-36 2.
List of Recently Issued Information Notices 1797 076 8061240 hn&
DEC 3 i IN Duke Power Company cc w/ encl:
J. T. Moore, Project Manager Post Office Box 422 Gaffney, South Carolina 29340 1797 077
UNITED STATES SSINS No.:
6870 NUCLEAR REGULATORY COMMISSION Accession No:
OFFICE OF INSPECTION AND ENFORCEMENT 7910250519 WASHINGTON, D.C.
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l M,O TP December 31, 1979
&g d1 IE Information Notice No. 79-36 COMPUTER CODE DEFECT IN STRESS ANALYSIS OF PIPING ELBOW Description of Circumstances:
The NRC was informed on December 17, 1979 that a computer code, NUPIPE, used in the stress analysis of piping systems contained a defect which could result in incorrect stress values at one end of piping elbows. This defect was iden-tified from discussions with a user of NUPIPE and the NUPIPE code developers.
The stress calculation error can occur when a flexible joint is modeled at the end of an elbow (ELB0W-ELAST0JT connection in NUPIPE terminology). This defect in tie NUPIPE code is in the transformation of the loads in the ELAST0JT coordi-nate axis to the piping ELBOW coordinate axis. The incorrect coordinate axis transformation may incorrectly interchange the torsion and bending moment loads on the piping elbow. This can result in the incorrect assignment of the stress intensification factor for the individual moments.
The correct stress may be higher or lower than calculated by NUPIPE, depending on the loading condition.
Four conditions must exist for the possibility of the calculation of an incorrect stress in the NUPIPE code:
1.
an USAS B31.1.0 - 1967 Code analysis is being done, and 2.
an ELBOW-ELAST0JT connection exists, and 3.
an absolute sum of two load cases is being calculated, and 4.
the ELB0W torsional moment axis does not align with the ELAST0JT local x-axis.
Possible users of the NUPIPE code include the code developer, Stone and Webster, EG&G (Idaho Falls), and those using the Cybernet system.
The NRC is currently reviewing the extent of usage of the NUPIPE code and the generic implications for other facilities. There is a potential for a similar defect to occur in other piping analysis computer codes.
This Information Notice is provided as early notification of a possible signif-icant matter.
It is expected that recipients will review the information for possible applicability to their facilities. No specific action is requested in response to this Information Notice.
If NRC evaluations so indicate, further licensee actions may be requested or required.
If you have any questions regarding this matter, please contact the Director of the appropriate NRC Regional Office.
No written response to this IE Information Notice is required.
1797 078
IE Information Notice No. 79-36 Enclosure December 31, 1979 RECENTLY ISSUED IE INFORMATION NOTICES Information Date Notice No.
Subject Issued Issued To 79-36 Computer Code Defect In 12/31/79 All holders of power reactor Stress Analysis of Piping OLs and cps Elbow 79-35 Control of Maintenance and 12/31/79 All holders of power reactor Essential Equipment OLs and cps.
79-34 Inadequate Design of Safety-12/27/79 All holders of power reactor Related Heat Exchangers OLs and cps 79-33 Improper Closure of Primary 12/21/79 All holders of power reactor Containment Equipment Access OLs and cps Hatches 79-32 Separation of Electrical 12/21/79 All power reactor facilities Cables for HPCI and ADS holding OLs and cps 79-31 Use of Incorrect Amplified 12/13/79 All power reactor facilities Response Spectra (ARS) holding OLs and cps 79-30 Reporting of Defects and 12/6/79 All power reactor facilities Noncompliances, 10 CFR holding OLs and cps and Part 21 vendors inspected by LCVIP 79-29 Loss of NonSafety-Related 11/16/79 All power reactor facilities Reactor Coolant System holding OLs or cps Instrumentation During Operation 79-28 Overloading of Structural 11/16/79 All power reactor facilities Elements Due to Pipe Support with an OL or CP Loads 79-27 Steam Generator Tube 11/16/79 All power reactor facilities Ruptures At Two PWR holding OLs and cps Facilities79-12A Attempted Damage To New 11/9/79 All Fuel Facilities, Fuel Assemblies research reactors, and power reactors with an OL or CP 79-26 Breach of Containment 11/5/79 All power reactor facilities Integrity holding OLs and cps 79-25 Reactor Trips At Turkey 10/1/79 All power facilities with Point Units 3 And 4 an OL or a CP 1797 079