Journals →  Chernye Metally →  2018 →  #12 →  Back

Metal Science and Metallography
ArticleName Actual conservative estimations of brittle fracture resistance of reactor pressure vessel steels for vver radiation lifetime prediction
ArticleAuthor N. P. Anosov, V. N. Skorobogatykh, L. Yu. Gordyuk, Zh. V. Yurgina
ArticleAuthorData

RF State Research Centre JSC SPA “CNIITMASH” (Moscow, Russia):

N. P. Anosov, Cand. Eng., Senior Researcher, e-mail: NPAnosov@cniitmash.com
V. N. Skorobogatykh, Cand. Eng., Director of Material Science Institute, e-mail: VNSkorobogatykh@cniitmash.com
L. Yu. Gordyuk, Senior Researcher, e-mail: LUGorduk@cniitmash.com
Zh. V. Yurgina, Engineer, e-mail: ZVUrgina@cniitmash.com

Abstract

The study considered the possibility of refusing to use the shift of the critical temperature of brittleness (ΔTC) in the assessment of irradiation embrittlement of VVER RPV (Reactor Pressure Vessel) materials. The methods of calculation brittle strength using critical brittle temperature or brittle-ductile temperature were examined as the alternative. The brittle-to-ductile transition temperature TP is determined immediately at the inflection point of the normal standard probability distribution, whereas the level of impact energy KCV corresponding to a given σ0.2 value intersects line of the normal standard probability distribution at the point TC that is located much lower and to the left from TP on the temperature diagram of impact toughness. When avoiding usage of ΔTC, the nonadditive summing ΔTC and TC0 is eliminated. Instead, actual radiation embrittlement coefficients TC0 = –60 °C, AF = 23, n = 1/3 are taken for calculation from the most conservative melt in terms of ΔTc among certification specimens lots of the base material, steel 15H2NMFAA. as the in for the base metal. In this case, the lifetime equal to 54 years is guaranteed. It was obtained that the refusal to use ΔTC in the assessment of irradiation embrittlement of VVER RPV steels allows us to statistically substantiate the actual resources:
– 210 years for 15H2NMFAA steel and 307 years for 15H2NMFA grade 1 steel based on ТC (avoiding using ΔTC) with TC0 = minus 77 °C;
– 117 years for 15H2NMFAA steel and 127 years for 15H2NMFA grade 1 steel based on ТP (statistically substantiated) with TC0 = minus 57 °C.
The work was financially supported by the Ministry of education and Science of Russian Federation in the framework of Agreement about granting of subsidy №14.579.21.0116 (unique agreement identificator RFMEFI 57915X0116).

keywords Brittle fracture resistance, lifetime prediction, reactor pressure vessel steels, critical brittleness temperature, ductile-to-brittle transition
References

1. Liu Y. J., Guo J., Gu K. K. Aging and Life Management System of Reactor Pressure Vessel. World Journal of Nuclear Science and Technology. 2011. Vol. 1. Iss. 02. p. 21.
2. Odette G. R., Nanstad R. K. Predictive reactor pressure vessel steel irradiation embrittlement models: issues and opportunities. JOM. 2009. Vol. 61, Iss. 7. pp. 17–23.
3. Anosov N. P., Skorobogatykh V. N., Gordyuk L. Yu., Mikheev V. А., Pogorelov Е. V., Shamardin V. К. Brittle fracture resistance of VVER shell steel in the initial state. Izvestiya vuzov. Yadernaya energetika. 2018. No. 1. pp. 134–145.
4. Hashmi M. F., Wu S. J., Li H. X. Neutron irradiation embrittlement modeling in RPV steels an overview. Proceedings of 18th international conference on structural mechanics in reactor technology (SMiRT) Beijing, China. August 7–12, 2005. pp. 35–42.
5. Dub V. A., Novikov S. V., Shchepkin I. A., Kornienko O. Yu. Improvement of the melting technology and ladle treatment of steels 15Х2НМФА (15Kh2NMFA) (A-A, class 1) for special critical duty components in nuclear power stations. CIS Iron and Steel Review. 2017. Vol. 14. pp. 8–13.
6. Goli-Oglu Е. А., Greisen G., Bokachev Yu. A. Research of metallurgical quality of heat-resistant low-alloyed molybdenum steel 16Mo3 in sheet with thickness up to 150 mm for shells of steam turbines. Chernye Metally. 2018. No. 6. pp. 53–57.
7. Specifi cation 0893-013-00212179-2003 Workpieces from the steel of grades 15Kh2NМFА, 15Kh2NМFА-А, 15Kh2NМFА class 1 for shells, covers and other units of NPP. Technical specifi cation. Introduced: 01.07.2003.
8. Kazantsev А. G., Markochev V. М., Sugirbekov B. А. Evaluation of accuracy to determine the critical temperature of VVER-1000 reactor shell metal brittleness using the Monte-Carlo method. Tyazheloe mashinostroenie. 2015. No. 9-10. pp. 19–27.
9. Lundgren M. Analysis of predictive models for correlation of irradiation effects on pressure vessel steels. Gothenburg: Chalmers University of Technology. 2010. 59 p.
10. Wallin K. Use of the Master Curve methodology for real three dimensional cracks. Nuclear engineering and design. 2007. Vol. 237. Iss. 12-13. pp. 1388–1394.
11. Odette G. R., Lucas G. E. Recent progress in understanding reactor pressure vessel steel embrittlement. Radiation effects and defects in solids. 1998. Vol. 144. Iss. 1-4. pp. 189–231.
12. PNAE G-7-002-86 Norms of calculations strength of NPP equipment and pipelines. Gosatomenergonadzor SSSR. Moscow: Energoatomizdat. 1987. 525 p.
13. Markov S. I., Durynin V. А., Mokhov V. А. Steel of grades 15Kh2NМFА, 15Kh2NМFА-А and 15Kh2NМFА class 1 for VVER-TOI reactor shell. Tyazheloe mashinostroenie. 2013. No. 3. pp. 2–5.
14. GOST R ISO 148-1-2013 Metallic materials. Charpy pendulum impact test.. Part 1. Test method. Moscow: Standartinform. 2014. 27 p. Introduced: 01.01.2014.
15. Vishkarev О. М., Dub V. S., Loboda А. S., Kashirsky Yu. V., Shamardin V. К., Zubova Т. N., Kalugina I. I., Kobelev N. N. Effect of impurities on radiation resistance of the shell pearlite steel 15Kh2NМFА. Proceedings of TsNIITMASh. 1980. No. 157. pp. 19–24.
16. Vishkarev О. М., Dub V. S., Loboda А. S., Shamardin V. К., Kobelev N. N., Kalugina I. I., Zubova Т. N. Radiation resistance of the steel 15Kh2NМFА. Proceedings of TsNIITMASh. 1980. No. 157. pp. 4–6.

Language of full-text russian
Full content Buy
Back