Kugelblitz ( Слушатель ) | |
16 мар 2017 17:36:58 |
Цитата: ЦитатаCounterfeit/obsolete Equipment and Nuclear Safety issues of VVER-1000 Reactors at Kudankulam, India
Counterfeit equipment is becoming a major threat to nuclear safety globally. The Kudanku-
lam Nuclear Power Plant (KKNPP) in India housing two VVER-1000 reactors, imported from
Russia is being delayed because of counterfiet, substandard and obsolete equitpment. The po-
lar crane, the limb of the reactor, is defective as its hoisting capacity is less than 80% of its
nameplate capacity. The crane is used for installing the equipment inside the reactor building
and also for removing spent fuel. The contract said that there will be no weld in the beltline
of the reactor pressure vessel (RPV). The received vessels have two circumferential welds on
the beltline. RPV, the heart of the reactor is irreplaceable and hence determines the life of
the reactor. RPV and polar crane are safety grade equipment. The core-damage frequency
(CDF) of the reactor in the contract was 10 −7 reactor-years, while the supplied reactor has
a CDF of 10 −5 reactor-years. Two units of generator transformers were received as damaged
and these were dismantled and reassembled at the site. This paper finds evidences of the
unethical practises of sale and use of obsolete and counterfeit reactor equipment and discusses
the global catastrophic risks with reference to the international nuclear safety standards.
ДядяВася ( Слушатель ) | |
16 мар 2017 21:13:51 |
ЦитатаA 2003 study commissioned by the European Commission remarked that "core damage frequencies of 5 × 10−5 [per reactor-year] are a common result" or in other words, one core damage incident in 20,000 reactor years.[3] A 2008 study performed by the Electric Power Research Institute, the estimated core damage frequency for the United States nuclear industry is estimated at once in 50,000 reactor years, or 2 × 10−5.[5]
Цитата1.2.17. В целях исключения необходимости эвакуации населения за пределами зоны планирования защитных мероприятий, устанавливаемой в соответствии с нормативными требованиями к размещению АС, следует стремиться к тому, чтобы оцененное значение вероятности установленного этими требованиями предельного аварийного выброса не превышало 10 Е -7 на реактор в год.
Kugelblitz ( Слушатель ) | |
17 мар 2017 00:21:26 |
ЦитатаЦитата: ДядяВася от 17.03.2017 01:13:51
Про швы, признаться, ничего не понял.
ЦитатаThe KKNPP contract was for a V412 model, which belongs to the 3rd generation of reactor designs
ЦитатаThe beltline welds of RPV was mentioned for the first time in a brochure published
by NPCIL in 1998. SK Agarwal, the Station Director of KKNPP mentions this in a paper published
in an international journal: ”the pressure vessel has no weld joints in the core region” and the ”design
features extensively negotiated” includes ”verification of the designs by Indian engineers who will also
over-see the quality of equipment, witness necessary inspection and testing during manufacture” [24]
ЦитатаHowever, the vessel now used has two welds in the core region“ [26]. The estimated CDF of the reactor, according to S. Bajaj, the then
Senior Executive Director (Safety), of NPCIL is 1 in 100,000 reactor years [27], hundred times higher than the promised one.
ЦитатаThe beltline region of RPVs fabricated during the 1980’s were made of three forged rings and had two circumferential welds.
The modern trend is to use one large ring without any weld. There is also strict regulation regarding the concentration of
neutron-sensitive elements such as nickel in base and weld metals [16]. VVER RPVs fabricated before
1990 had high nickel-manganese content in the base metal and weld metal.
ЦитатаDuring the 1990’s, Europe including Russia, tightened their standards for PWR RPVs.
(Since 1990, Russian General Regulations for Nuclear Power Plant Safety requires a CDF of one in 10
million reactor years, [45] the pre-1990 RPVs with beltline welds have a CDF of one in 100,000 years.)
Under the new regulations, Soviet era RPVs made of high nickel-manganese steel and with beltline welds are not acceptable in Europe.
basilevs ( Слушатель ) | |
17 мар 2017 13:04:48 |
Kugelblitz ( Слушатель ) | |
17 мар 2017 14:14:20 |
Цитата: basilevs от 17.03.2017 13:04:48
ЦитатаThe AERB revealed in 2008 (three years after the receipt and one year after its installation) that the original design of RPV did not contemplate welds in the core region. However, the vessel now used has two welds in the core region“ [26].
mse ( Слушатель ) | |
17 мар 2017 15:18:08 |
Kugelblitz ( Слушатель ) | |
17 мар 2017 21:38:41 |
Цитата: mse от 17.03.2017 15:18:08
ЦитатаThe bottom portion of the RPV, known as the beltline is more vulnerable for premature ageing (a process known as embrittlement) due to the impact of neutrons flying away from fuel assembly during the chain reaction.
ЦитатаThe beltline region of RPVs fabricated during the 1980’s were made of three forged rings and had two circumferential welds. The modern trend is to use one large ring without any weld.
basilevs ( Слушатель ) | |
18 мар 2017 08:19:12 |
basilevs ( Слушатель ) | |
17 мар 2017 18:21:39 |
basilevs ( Слушатель ) | |
17 мар 2017 18:23:25 |
Osq ( Слушатель ) | |
17 мар 2017 19:01:47 |
ДядяВася ( Слушатель ) | |
17 мар 2017 19:49:47 |
Цитата: Osq от 17.03.2017 19:01:47
mark.76 ( Слушатель ) | |
18 мар 2017 16:16:36 |
Цитата: ДядяВася от 17.03.2017 19:49:47
Налим_23 ( Слушатель ) | |
18 мар 2017 17:49:25 |
Цитата: mark.76 от 18.03.2017 16:16:36
ДядяВася ( Слушатель ) | |
18 мар 2017 19:22:12 |
Цитата: mark.76 от 18.03.2017 16:16:36
mse ( Слушатель ) | |
17 мар 2017 18:05:23 |
Цитата: ДядяВася от 17.03.2017 17:28:16
basilevs ( Слушатель ) | |
16 мар 2017 22:03:54 |