Fatigue usage factor evaluation for integrally reinforced branch connection using NB-3600 and NB-3200 analysis methods

Book · Fri Dec 01 04:00:00 EST 1995

OSTI ID:136824

Hwang, H L ^[1]; Cole, J R; Bosi, D M ^[2]

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1. General Electric Nuclear Energy, San Jose, CA (United States)
2. Washington Public Power Supply System, Richland, WA (United States)

This paper presents the results of an ASME Section 3, Class 1, analysis of a 12 inch diameter integrally reinforced branch connection in a 24 inch diameter recirculation pipe. The branch connection was analyzed for internal pressure, external bending moments and thermal transient loading as required for Level B service conditions. The analysis was required since the nuclear plant operating conditions were revised to facilitate the plant preferred shutdown method. The NB-3200 analysis was completed after it was found that the branch connection fatigue usage exceeded the Code allowable limits when the simplified analysis method of NB-3600 was applied. The simplified analysis assumed that the maximum stress in the branch connection, due to the various moments and thermal transient loads, occurred at the same location. Furthermore, the simplified analysis uses an absolute sum method to combine the maximum stresses from each load condition. Whereas the detailed finite element analysis shows that the maximum stress location is different for each load condition. Therefore, when the individual element stresses are combined per NB-3200 methods the resulting usage factor was reduced to less than 0.1.

• OSTI ID: 136824
• Report Number(s): CONF-950740--; ISBN 0-7918-1344-4
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
CALCULATION METHODS
FATIGUE
FINITE ELEMENT METHOD
NUCLEAR POWER PLANTS
PIPES
PRESSURE DEPENDENCE
REACTOR COOLING SYSTEMS
REACTOR SHUTDOWN
STANDARDS
STRESS ANALYSIS
STRESS INTENSITY FACTORS
THEORETICAL DATA