ML19262B893
| ML19262B893 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 12/28/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Hines E DETROIT EDISON CO. |
| References | |
| NUDOCS 8001160302 | |
| Download: ML19262B893 (1) | |
Text
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UNITED STATES g
8 NUCLEAR REGULATORY COMMISSION o
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a a REGION ill 799 ROOSEVELT ROAD GLEN ELLYN, ILLINOIS 60137 Docket No. 50-341 The Detroit Edison Company ATTN: Mr. Edward Hines, Assistant Vice President and Manager Quality Assurance 2000 Second Avenue Detroit, MI 48226 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,
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(/ James G.
ler Director
Enclosure:
IE Information Notice No. 79-36 cc w/ enc 1:
Central Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC Ronald Callen, Michigan Public Service Commission Eugene B. Thomas, Jr.,
Attorney
'1754 339 O
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UNITED STATES SSINS No.:
6870 NUCLEAR REGULATORY COMMISSION Accession No:
OFFICE OF INSPECTION AND ENFORCEMENT 7910250519 WASHINGTON, D.C.
20555
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" VS December 31, 1979 d
u6 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 (ELBOW-ELAST0JT connection in NUPIPE terminology).
This defect in the NUPIPE code is in the transformation of the loads in the ELAST0JT coordin-ate axis to the piping ELB0W coordinate axis. The incorrect coordinate axis transformation may incorrectly interchange the torsion and bending moment loads en the piping elbow.
This can result in the incorrect assignment of the stress intensif':ation 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 ELBOW 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 info-mation for possible applicability to their facilities.
No specific action is requested in response to this Information Notice.
If HRC evaluations so indicate, further licensee actions may be requested or required.
If you have any questions regarding this matter, please contact the Directo of the appropriate NRC Regional Office.
No written response to this IE Information Notice is required.
Enclosure:
List of Recent1" Issued Information Noticos 754 340
i IE Information Notice No. 79-36 Enclosure December 31, 1979 RECENTLY ISSUED IE INFORMATION NOTICES Information Subject Date Issued To Notice No.
Issued 79-35 Control of Maintenance 12/31/79 All power reactor facilities and Essential Equipment with an OL or CP 79-34 Inadequate Design of 12/27/79 All holders of power reactor Safety-Related Heat OLs and cps Exchangers 79-33 Improper Closure of 12/21/79 All power reactor facilities Primary Containment holding OLs and cps Access 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 holders of power reactor Response Spectra (ARS)
OLs and cps 79-30 Reporting of Defects and 12/6/79 All power reactor facilities Noncompliance, 10 CFR Part 21.
holding OLs and cps and 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 reactqr facilities Ruptures At Two PWR holding OLs and cps Facilities79-32A i,ttempted Damage To New 11/9/79 All Fuel Facilities, Fuel Assemblies research reactors, and power reactors with an OL or CP 79-26 Breach or Containment 11/5/79 All power reactor facilities Integrity holding OLs and~ cps 1754 34f