atw Vol. 63 (2018) | Issue 3 ı March
ENVIRONMENT AND SAFETY 158
32. A. Carnino, M. Gaparini, Defense in
depth and development of safety
requirements for advanced reactors.
Workshop on Advanced Nuclear
Reactor Safety Issues and Research
Needs, Paris; February 18–20, 2002.
33. IAEA, Defence in Depth in Nuclear
Safety, IAEA; INSAG-10, IAEA, Vienna,
1996.
34. J.N. Sorensen, G.E. Apostolakis, T.S.
Kress, D.A. Powers, on the role of
defense-in-depth in risk informed
regulation. Presented at PSA’99,
Washington DC, USA, August 22–25,
La Grange Park, IL, USA: American
Nuclear Society; 1999.
35. M. Modarres, Advanced nuclear power
plant regulation using risk-informed
and performance-based methods,
Reliability Engineering and System
Safety, College Park, MD 20874, USA,
2009.
36. H.G. Kang, T. Sung, An analysis of safety-critical
digital systems for risk-informed
design, Reliability Engineering
and System Safety, Taejon 305-600,
South Korea, 2002.
37. I.S. Kim, T.K. Kim, M.C. Kim, B.S. Kim,
S.W. Hwang, K.C. Ryu, Suitability review
of FMEA and reliability analysis for
digital plant protection system and
digital engineered safety features
actuation system. KINS/HR-327; 2000.
38. I. S. Kim, S.K. Ahn, K.M. Oh, Deterministic
and risk-informed approaches
for safety analysis of advanced reactors:
Part II, Risk- informed approaches,
Reliability Engineering and System
Safety, Daejeon 305-338, Republic of
Korea, 2010.
39. M.C. Jacob, J.P. Rezendes, Development
of risk informed safety analysis
approach and pilot application.
Westinghouse, WCAP-16084-NP, rev 0,
September, 2003.
40. DOE, USNRC, Next generation nuclear
plant licensing strategy – a report to
congress, August, 2008.
41. M.J. Delaney, G.E. Apostolakis, M. J.
Driscoll, Risk-informed design guidance
for future reactor systems, Nuclear
Engineering and Design, Cambridge,
MA 02139-4307, USA, 2005.
42. G.E. Apostolakis, How useful is
quantitative risk assessment?, Risk Anal.
24, 515–520, 2004.
43. G.E. Apostolakis, M.W. Golay, A.L.
Camp, A.L. Duran, D.J. Finnicum, S.E.
Ritterbusch, June 4–5, A new riskinformed
design and regulatory
process. In: Proceedings of the Advisory
Committee on Reactor Safeguards
Workshop on Future Reactors, Report
NUREG/CP-0175, pp. p237–p248, US
Nuclear Regulatory Commission,
Washington, DC, 2001.
44. A. Lyubarskiy, I. Kuzmina, M. E.
Shanawany, Advances in Risk Informed
Decision Making – IAEA’s Approach,
Vienna, Austria, 2011.
Authors
Mohsen Esfandiari
Gholamreza Jahanfarnia
Department of Nuclear
Engineering
Science and Research Branch
Islamic Azad University, Tehran,
Iran
Kamran Sepanloo
Ehsan Zarifi
Reactor and Nuclear Safety
Research School
Nuclear Science and Technology
Research Institute (NSTRI), Tehran,
Iran.
Applied Reliability Assessment for the
Passive Safety Systems of Nuclear Power
Plants (NPPs) Using System Dynamics (SD)
Yun Il Kim and Tae Ho Woo
1 Introduction A new kind of passive system is investigated in case of an accident in nuclear power plants
(NPPs). Conventional passive systems have the limitations in the conditional integrity like the piping system of the
coolants. In this paper, the free-falling of emergency coolants are proposed where the flying machine, drone, is imported
to carry out the coolants on the upper position of the containment building. In the cases of the Fukushima and Chernobyl,
the piping systems were blown away. So, the emergency coolants couldn’t flow into the reactor core position where the
reactor fuels were making continuous very high energy without stabilizing of the power level. Although the integrity of
the piping injection systems have been investigated as the good conditions, the previous history couldn’t give the
satisfactions to the public.
During the Fukushima disaster, the
operator had been seeking for the
prime minister to take a permission to
open the gas leak valve in the containment
building when the reactor pump
was out of order and the hydrogen
gases were produced continuously.
Eventually, the hydrogen explosion
happened and the four plants were
collapsed within several days after
East-Japan earthquake impact on the
Fukushima coast and its related areas.
Furthermore, even if there was an
opportunity to make use of the sea
water in order to cool down the
reactor core, the operator didn’t use it
for keeping the expensive reactor
structure from the saluted sea water
in which the material corrosions could
been happened and the material could
be in the significantly damaged situation.
Then, all kinds of the cooling
systems were gone permanently.
The dangerous radioactive contaminations
to the environment have been
done continuously. Considering the
case of the Fukushima nuclear accident,
the piping system has the crucial
fault that the safety system can’t
make any role in the post-accident or
on-accident. Piping in the NPPs should
be incorporated with the alternative
coolant supply method. So, the
detached system from plant building
could be imagined in this study.
The merit of the passive system is
operated without in-site electricity.
So, the natural circulation or gravity
could be acted for the designed system
by injection of the coolants. However,
even the action of switch of the system
operation should be done to start. So,
the manual based stating action is
needed for the operation of passive
system. As the same condition of the
Environment and Safety
Applied Reliability Assessment for the Passive Safety Systems of Nuclear Power Plants (NPPs) Using System Dynamics (SD) ı Yun Il Kim and Tae Ho Woo
Change language