Calculation of the valve with the bellows

Description of the valve

Stop valve with the bellows, DN10, Pp20, Tp300, material 08Ch18N10T, operation by the manual wheel.

Task of the calculation

Calculation of the strength and lifetime of the valve body according to the requirements
in the document OTT-87 (VTP 87/91).

Description of the calculation

Calculation loadcases for the static strength control were chosen in accordance with the requirements of the document OTT-87 as well as in accordance with the assumable operating condition of the valve in the location of its installation.

Lifetime of the valve body and nozzles was determined for all loadcases (also number of their repetitions) defined
in OTT-87. Loadcases for the primary circuit were chosen acc. Annex 2 (WWER 1000), loadcases for the secondary circuit were chosen acc No. 3.24 in addition of the loadcase with the fast heating of the body by the medium
of the temperature 150°C.

Resistance of the valve body and nozzles during the seismic event was checked by the piping loads at MDE level
(Annex 4) and by the accelerations according to the requirements of the chapter 7.6 in OTT-87.

Assessment of the results

The respective stress categories (σ1, σ2, σRV, σs1, σs2) were calculated during all loadcases. These stresses were compared with their limit ones determined according to the document PNAE G-7-002-86.

Maximum alternating fictitious stress intensities (σaF) were determined from the stresses gained by the analysis of the respective loadcases. Alternating stress intensities and defined number of cycles were subsequently used for the calculation of the damage accumulation in STATES software in accordance with the methodology in the document
PNAE G-7-002-86.

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