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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3. Analysis by the Finite Element Method The discretization of the structural model of the BWR reactor building crane is shown in Fig. 1a. The model has 62069 hexahedral elements (SOLID 186) with 405807 nodes. The Minimum Element Quality is 0.21861 and this value is adequate as recommended by ANSYS (ANSYS, 2016). The boundary conditions of the structure of the BWR reactor building crane are shown in Fig. 1b. Fixed supports were considering in the runway beams (Item A and B showed in Fig. 1b).

Table 2. General specifications of the BWR reactor building crane (Greiner, 1967). General Measure Operation velocities

Measure 0.254 m/s 0.2032 m/s 0.01524 m/s

Crane span

40 m

Crane

Distance between wheels of trolley Distance between bridge girders

4 m

Trolley Hoisting

7.5 m

a

b

Fig. 1. Model of the BWR reactor building crane (a) Mesh and (b) Boundary conditions of the reactor building crane.

The dead loads considered were of the weight of the bridge, the trolley and the runway beams. Besides, the live loads (USNRC, 1980) such as the horizontal load due to the acceleration or deceleration of the live load and the impact loads were taken into account also. These loads are F y =trolley dead load+live load+vertical impact load and F x = (trolley dead load+live load)x0.5 (ASME-NOG-1-2004, 2004; CMAA, 2000; Greiner, 1967). They are function of the operation performed by the crane (cyclic loads). The data reported in the applications for license renewal of the nuclear plants of Limerick (USNRC, 2014) and LaSalle (USNRC, 2016) were considered, as shown in Table 3.

Table 3. BWR Reactor Building Crane Load Cycles (Greiner, 1967; USNRC, 1980). Heavy Load Description Fy [N] Fx [N]

Total cycles n

Plant Construction Cycles Refueling Outage Cycles Load Test Reactor Vessel Head

1 799 521

83 357

10000

2 363 403 1 754 410 1 190 528 1 551 412 1 348 415 1 551 412 835 282 897 309 2 047 629

107 873 81 395 56 879 72 569 63 743 72 569 41 433 44 130 94 144

60

120 120 120

Drywell Head

Reactor Vessel Steam Separator

Shield Plug

1200 360 120 240 1968

Dryer/Separator Canal Plugs

Work Platform Miscellaneous

Waste Cask Load Cycles

4. Cumulative Usage Factor (CUF)

The determination of the CUF requires the number of applied cycles n (Table 3) and the number of cycles to failure N f for each cyclic load.