WWER-1000 pressure vessel

The beltUne regions of the WWER-440A -213 (i.e. second generation) pressure vessels were also manufactured from 15Kh2MFAA steel, but most of the V-213 pressure vessels have low phosphorus and copper contents and are similar in impurity content to the WWER-1000 pressure vessels with strict requirements on the residual element (copper, phosphorus, arsenic, tin and antimony) content, i.e. their steel and welds are of 15Kh2NMFAA quality. Thus, radiation embrittlement does not seem to be a limiting factor... 

Abstract This chapter describes requirements for speciality WWER reactor pressure vessel materials in terms of their chemical composition and mechanical properties. The main principles of manufacturing technology for WWER pressure vessel fabrication are also discussed, including welding and cladding. 

OSMERA, B., Experimental and theoretical investigations for WWER pressure vessel neutron exposure evaluation in Czechoslovakia. Nuclear Data for Radiation Damage Assessment and Related Safety Aspects. IAEA-TECDOC-572 (1989). 

Key words WWER reactor pressure vessel, chemical composition, mechanical properties, welding, cladding. 

The WWER RPVs (as well as all other components) must be transportable by land, i.e. by train and/or by road. This requirement has some very important consequences on vessel design, such as a smaller pressure vessel diameter, which results in a smaller water gap thickness and thus a higher neutron flux on the reactor vessel wall surrounding the core and, therefore, requirements for materials with high resistance... 

Irradiation Embrittlement of Reactor Pressure Vessels (RPVs) Table 3.4 Requirements for chemical composition of WWER RPV materials... 

B.Timofeev, M. Brumovsky, and U. von Estorff, Certification Report oflSKhlMFA/ 15Cr2MoVA Steel and its Welds for WWER Reactor Pressure Vessels, IRC 57754, Petten, Netherlands EUR 24581 EN, Luxemburg, 2010. 

Embrittlement of reactor pressure vessels (RPVs) in WWER-type reactors... 

Abstract This chapter describes the embrittlement processes in WWER reactor pressure vessel (RPV) materials during operation - radiation embrittlement and thermal ageing. Current trend curves for both types of WWER RPV materials are given and explained. Surveillance specimen programmes are shown, as their results are used for RPV integrity and lifetime evaluation. Finally, anneahng of the RPV is proposed as the most efficient mitigation measure. 

Characteristics of embrittlement of WWER reactor pressure vessel (RPV) materials... 

IAEA, Guidelines for Prediction of Irradiation Embrittlement of Operating WWER-440 Reactor Pressure Vessels, IAEA TECDOC 1442, International Atomic Energy Agency, Vienna, 2005. 

The reference temperature NDT, RTf, is also an index temperature used as a normalization tool to compare the behaviour of different materials and different heats of materials. The RTndt is determined according to procedures outUned in the ASME Boiler and Pressure Vessel Code (ASME, 2013 a) and is a combination of the NDT temperature and Charpy impact test results. Briefly, the RTndt is the higher of either the NDT temperature or Tso - 60°F (33 C), where T q is the temperature at which three Charpy impact specimens achieve energy and lateral expansion values of at least 50 ft-lb (68 J) and 0.035 in. (0.89 mm), respectively. A more detailed discussion of this reference temperature can be found in Chapter 1. Similarly, for WWER RPVs, the CVN-based temperature called the critical temperature of brittleness, 21, is used as a reference temperature. These references are discussed in subsequent sections as used for various test methods. 

Amayev A D, Kryukov A M and Sokolov M A (1993), Recovery of the transition temperature of irradiated WWER 440 vessel metal by annealing, pp. 369-379 in Radiation Embrittlement of Nuclear Reactor Pressure Vessel Steels An International Review (Fourth Volume), ASTM STP1170, L E Steele, ed., American Society for Testing and Materials, Philadelphia, PA. 

B. Z. Margolin, V.A. Nikolaev, E.V. Ynrchenko, Y.A. Nikolaev, D.Y. Erak and A.V. Nikolaeva, Analysis of embrittlement of WWER-1000 RPV materials. International Journal of Pressure Vessels and Piping, 89,2012,178-186. 

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