PSI - Issue 17

Juan Cruz Castro et al. / Procedia Structural Integrity 17 (2019) 115–122 Juan Cruz Castro et al./ Structural Integrity Procedia 00 (2019) 000 – 000

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BWR CFR CUF IAEA CMAA NUREG USNRC TLAA

Boiling Water Reactor Code of Federal Regulations

Crane Manufacturer Association of America

Cumulative Usage Factor

International Atomic Energy Agency

NRC technical report

United States Nuclear Regulatory Commission

Time-Limited Aging Analysis Number of applied cycles Number of cycles to failure

n

σ ƒ σ ƒ” σ  σ ̵ ˆ σ —

N f

Stress ratio

γ

Fitting constant for the Walker method

Alternating stress

Equivalent completely reversed stress amplitude

Mean stress

True fracture strength Ultimate tensile strength

2. BWR reactor building crane

Table 1 shows that the structural girders of the BWR reactor building crane are part of the components that have an Aging Management Program as marked by NUREG 1801 R2 (USNRC, 2010). It requires a TLAA of fatigue according to NUREG 1800 R2 (USNRC, 2010). Therefore, this work seeks to evaluate if the structural girders can fulfil their functions during the extension period of the operating license. In case of any failure, it could cause the fall of heavy loads such as spent fuel, core fuel or equipment that may be necessary to achieve a safe shutdown of the reactor or allow the removal of residual heat, thus compromising the security and integrity of the plant.

Table 1. Aging Management Program for cranes according to NUREG 1800 (USNRC, 2010).

Component

Aging Effect/Mechanism Loss of material due to general corrosion

Aging Management Programs

Further Evaluation

Chapter XI.M23, “Inspection of overhead heavy load and light load handling systems”

Steel cranes: Rails and structural girders

No

Chapter XI.M23, “Inspection of overhead heavy load and light load handling systems Fatigue is a Time-Limited Aging Analysis (TLAA) to be evaluated for the period of extended operation for structural girders of cranes that fall within the scope of 10 CFR 54 (Standard Review Plan, Section 4.7, “Other Plant -Specific Time- Limited Aging Analyses,” for generic guidance for meeting the requirements of 10 CFR 54.21(c)(1))

Steel cranes: Rails Loss of material due to wear

No

Steel cranes: Structural girders

Cumulative fatigue damage due to fatigue

Yes, TLAA

A BWR reactor building crane in the United States of American USA must be designed to meet the fatigue requirements of the ASME NOG-1-2004 (ASME, 2004) and the Crane Manufacturer Association of America (CMAA) Specification 70 (CMAA, 2000) for a Class A, standby or Infrequent Service Crane. The evaluation of load cycles over the 40-year plant life is the basis of a safety determination and has been identified as a TLAA that requires evaluation for the period of extended operation. The general dimensions and operation velocities the BWR reactor building crane are postulated based on generic measurements (Greiner, 1967) and they are shown in Table 2. The proposed study is supported with a Finite Element Method analysis. The ANSYS code was used. A three dimensional model of the crane has been developed. The bridge girders and the runway beams were considered.