1. TACIS Project: R8.01/98 – TRANSLATION, EDITING AND DIFFUSION OF DOCUMENTS (Result Dissemination) TACIS R2.08/92 Stress Analysis in VVER-1000-Containment Slide 1 Rev.: 21.8.2005  Beneficiary:Rosenergoatom  Contractors:Coyne et Bellier  Local Subcontractor: DIAPROM; AEP-Moscow  Sector of activities: Design Safety  Sites: All VVER 1000 NPPs  Installations: VVER 1000  Status: Completed  Budget: 890 000 €  Duration: 30 months Project General Data

2. TACIS Project: R8.01/98 – TRANSLATION, EDITING AND DIFFUSION OF DOCUMENTS (Result Dissemination) TACIS R2.08/92 Stress Analysis in VVER-1000-Containment Slide 2 Rev.: 21.8.2005 Objectives of the Project  A stress analysis was to be performed on VVER-1000 (small & large series)  To estimate the minimum pre-stressing level of WER-1000 NPP containments, wherein the containments are able to perform their functions in any operating condition stipulated in the design.  The required pre-stressing level was defined on the basis of the stress- strain analysis computed with COYNE ET BELLIER computers programs.

3. TACIS Project: R8.01/98 – TRANSLATION, EDITING AND DIFFUSION OF DOCUMENTS (Result Dissemination) TACIS R2.08/92 Stress Analysis in VVER-1000-Containment Slide 3 Rev.: 21.8.2005 The Containments of the VVER 1000 are characterized by:  Geometry (small and large series similar)  Inner Cylinder Diameter:45 m  Cylinder wall 1 200 mm  Dome wall1 100 mm  Links of internal and external structure: none  Pre-stress (different between small and large series)  Tendons of the dome pre-stressing system are arranged in an orthogonal pattern of two mutually perpendicular layers. In the containment of Unified series each tendon has 2 active (tension) anchors on one side of dome ring girder and a kink on the opposite side. Each tendon of the Small series containment is tensioned on one side of the dome ring girder and has its passive (dead) anchor on the other side. Containment features (1)

4. TACIS Project: R8.01/98 – TRANSLATION, EDITING AND DIFFUSION OF DOCUMENTS (Result Dissemination) TACIS R2.08/92 Stress Analysis in VVER-1000-Containment Slide 4 Rev.: 21.8.2005 Containment features (2)  Pre-stress (Continuation)  The global friction coefficient of tendons on wall ducts is assumed to be equal to б = 0,085; this value has been obtained from experimental data on Unified and Small series containments. Stress variation along the length of pre-stressing tendons is computed according to Eiler’s law.  Material  Both containment types are made of Concrete B 30 class  To provide leak-tightness on the internal surface of containments a 8 mm thick metallic gas-tight liner made of class 3 steel is anchored into concrete.

5. TACIS Project: R8.01/98 – TRANSLATION, EDITING AND DIFFUSION OF DOCUMENTS (Result Dissemination) TACIS R2.08/92 Stress Analysis in VVER-1000-Containment Slide 5 Rev.: 21.8.2005 Adopted Pre-stress Criteria Criterion 1: In any containment section, except for zones of local discontinuities as well as for zones of containment supported by the foundation (in the region of containment bottom plate, ring girder), the longitudinal force from containment pre-stressing is not less than the force which arises from an applied internal pressure equal to ΔP = 1,15 MPa Criterion 2: Strength requirements shall be met in any operating mode stipulated in the design including design basis accident and simultaneous design basis earthquake, any containment section,

6. TACIS Project: R8.01/98 – TRANSLATION, EDITING AND DIFFUSION OF DOCUMENTS (Result Dissemination) TACIS R2.08/92 Stress Analysis in VVER-1000-Containment Slide 6 Rev.: 21.8.2005 Tools and methods used for Analysis Computer Hard- and Software: The analysis of containment stress-strain state was performed on a HP - Workstation and on PCs using codes transferred by COYNE ET BELLIER (see list of codes in the Executive Summary) Training: AEP specialists were trained at COYNE ET BELLIER in order to work with the above mentioned computer codes,

7. TACIS Project: R8.01/98 – TRANSLATION, EDITING AND DIFFUSION OF DOCUMENTS (Result Dissemination) TACIS R2.08/92 Stress Analysis in VVER-1000-Containment Slide 7 Rev.: 21.8.2005 Results of the Analysis (1) The analysis showed, that the least safety factors were calculated in the lower region of membrane zones of cylindrical containment part (meridian direction) and for horizontal sections adjacent to a large hole on the elevation of its axis. Tensile forces recorded separate (e.g. in dome zenith) are determined by the effect of temperature thrust of the leak-tight steel liner. The highest stresses (strains) in elements of reinforced concrete containment sections were observed 1 hour after start of an accident which can be explained by the heating effect with relatively slow drop of positive pressure (as compared with maximum in the first seconds of an accident). Analyses showed that under the preset pre-stressing level (based on criterion 1) in anyone of the operating regimes stipulated in the design, including design basis accident conditions, in combination with the design basis earthquake, strength requirements are met in compliance with criterion 2.

8. TACIS Project: R8.01/98 – TRANSLATION, EDITING AND DIFFUSION OF DOCUMENTS (Result Dissemination) TACIS R2.08/92 Stress Analysis in VVER-1000-Containment Slide 8 Rev.: 21.8.2005 Results of the Analysis (2) Based on the analysis carried out, the following forces at the anchor heads can be considered as necessary and sufficient: 1) For containments of unified series: in cylinder7,7 MN; in dome7,6 MN. 2) For containment of small series: in cylinder7,2MN; in dome6,9 MN.