[email protected]rg Am erican N uclearSociety 2001 A nnualM eeting M ilw aukee W I,June 17 -June 21 Safety C ulture and its R elationship to Econom ic Value in the C om petitive M arket: A G lobal Perspective W orldwide Em bedded Topical M eeting: N uclearSafety G oals and Safety C ulture Sponsored by AN S/AESJ Prom oting and Assessing an Im proved Safety C ulture Accidentand C onsequence Analyses Lessons to learn Three M ile Island‘79,C hernobyl’86,TokaiM ura’99 and the N ew Era ofthe European N uclearIndustry Frigyes Reisch KTH,R oyalInstitute ofTechnology (the technical university of Stockholm ,Sw eden) [email protected]
Three Mile Island, TMI - 2. TMI-2 normal operation. No true position indication of the valve. No temperature measurement upstream and downstream the valve. Erroneous level indication in the pressuriser. No water level measurement in the reactor vessel. TMI2 + 1 ½ h. - PowerPoint PPT Presentation
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AbstractThree Mile Island (Harrisburg, USA), Chernobyl (Ukraine) and Toka Mura (Japan) are the threemost publicised accidents of the nuclear industry. The plants are on different Continents, havevery different features and the accidents are very much unlike in nature. Nevertheless theseaccidents have many similar characteristics;
the precursors were not properly evaluated and consequently the proper conclusionswere not established, appropriate remedies were not applied to avoid similar accidents,
due to insufficient instrumentation the operators were denied much needed information -about the status of the process they controlled - to be able to make the correctdecisions,
the operators were not trained to recognise the importance - of the awareness - ofobserving deviations from normal conditions, at an early stage, to avoid accidents,
they were not trained either to be prepared to meet the challenges of unexpectedoccurrences,
the management did not see the activities at the plant through the operators’ eyes, the management did not realise the price of the “profit” of meeting time schedules by
pressuring people.
The new millennium started with an entirely new industrial landscape# The national and regional electrical grids are integrated into a huge European grid. The
rules of the electricity market changed entirely.# Reactor manufacturers are becoming fewer and bigger. For example the original
suppliers of the Swedish nuclear power plants are now in the hand of a single owner.
- precursors were not thoroughly evaluated and consequently thecorrect conclusions were not deduced
- the operators lacked the necessary information about the statusof the process they controlled to be able to make the rightdecisions
- the operators lacked training to observe deviations at an earlystage to avoid accidents as well as their preparedness to meetthe challenges of unexpected occurrences was insufficient
- management did not see the activities at the plant through theoperators’ eyes
- the price of the “profit” of meeting time schedules by pressuringpeople was not assessed properly
- The accident occurred in the middle of the night whenwork was to be rushed.
- After a transient, a valve on the pressurizer remainedopen and steam escaped continuously.
- The instruments erroneously indicated full pressurizerwhile the reactor vessel were emptied and the primarywater was amassed on the containment floor.
- Due to inadequate containment instrumentation theoperators could not recognize the actual situation.
- The operators were drilled to open the let down lineand stop water injection to the reactor vessel whenthe level measurement indicated full pressurizer.
- There were several precursors. Previous incidentsshowed the need for level measurement in the reactorvessel proper, at an other occasion the containmentfloor was flooded without the operators noticing it.
- After the accident neither the industry nor the safetyauthority admitted thier negligence. Thecomplementary instrumentation was installed yearslater and some is still missing.
- This disaster happened in the middle of the nightwhen an experiment was due to be rushedthrough to make place to the refueling crew.
- During the experiment large amount of steamwas produced in the reactor which in conjunctionwith the positive void coefficient caused supercriticality and blew up the reactor.
- The immediate past history of power productioncreated a heavily xenon poisoned reactor corewith a most peculiar axial power profile.
- The operators were not aware of this because ofthe lacking instrumentation.
- There were several precursors, incidents at otherRBMK plants which were not properly evaluatedand the lessons were not applied.
- After the incident all the blame was put on thegrass roots.
- Nevertheless major changes were made in thedesign.
Northern Europe- Around the Baltic Sea there is a cluster of the most widely used
reactor types in operation;- There are pressurised water reactors of both western (PWR) and- Russian (VVER) types,- boiling water reactors (BWR) of Swedish and German manufacture,- a boiling heavy water reactor (BHWR) in Norway and- graphite moderated boiling water cooled pressure tube reactors (RBMK)
of Russian design.- - These reactors are not only of different types, they are also of
different sizes.- The BHWR is a low power research reactor of some 10 MWt while- the BWRs, PWRs and VVERs are of medium to large sizes, from some
100 to more than 1000 MWe.- RBMKs are among the most powerful reactors of all categories – well
over a GWe.
- The Baltic Ring Project, now under development in Scandinavia, isintended to link all the nuclear reactors surrounding the Baltic Sea into apowerful grid.
European Industry: Fewer and Bigger Manufacturers
- Since the beginning of this new century all the original suppliers of theSwedish reactors ABB and Westinghouse are owned by BNFL, BritishNuclear Fuel Limited controlled from London by the government, whilethe
- original supplier of the German plants, Siemens is controlled by thelargely Paris government owned Framatom, the supplier of the Frenchnuclear power plants.