Engineering Failures Lessons in Professional Ethics A Case Study Outline of Presenta;on

Engineering  Failures  –  Lessons  in  Professional  Ethics  –  A  Case  Study   Outline  of  Presenta;on   ²  ²  ²  ²  ²  ²    Basis  for  Pr...
Author: Amy Singleton
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Engineering  Failures  –  Lessons  in  Professional  Ethics  –  A  Case  Study   Outline  of  Presenta;on   ²  ²  ²  ²  ²  ²   

Basis  for  Professional  Ethics   Laws  RelaDng  to  Engineering  Work   A  Case  Study  -­‐  Pipe  Break  Due  to  Relief  Valve  Cha6er   Summary  of  the  Ethical  Lessons  for  Engineers   Unexpected  Technical  Lessons  for  Engineers   Q&A  period.  

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Engineering  Failures  –  Lessons  in  Professional  Ethics  –  A  Case  Study   Basis  for  Professional  Ethics   ²  The  Ontario  Professional  Engineers  Act    h6p://www.ontario.ca/laws/statute/90p28     ²  RegulaDon  941  -­‐  Code  of  Ethics    h6p://www.ontario.ca/laws/regulaDon/900941     ²  PEO  Professional  Engineering  PracDce  Guidelines    h6p://peo.on.ca/index.php/ci_id/22127/la_id/1.htm    

²  Other  PEO  Guidelines  are  available  as  a  free  download  at:      h6p://peo.on.ca/index.php/ci_id/1834/la_id/1.htm    

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Engineering  Failures  –  Lessons  in  Professional  Ethics  –  A  Case  Study   Laws  Rela;ng  to  Engineering  Work   ²  Ontario  acts  and  associated  regulaDons,  visit:    h6p://www.e-­‐laws.gov.on.ca   ²  Federal  acts  and  associated  regulaDons,  visit:        h6p://laws-­‐lois.jusDce.gc.ca/eng/acts/   ²  These  are  the  laws  that  are  more  likely  to  get  you  into   serious  trouble  if  you  don’t  know  your  obligaDons.  All  are   available  as  a  free  download.   ²  Also  remember  that  some  of  these  laws  require  certain   industry  standards  to  be  followed  (eg:  ASME  piping  and   pressure  vessel  code,  CSA  electrical  wiring  code,  etc.)  

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Engineering  Failures  –  Lessons  in  Professional  Ethics  –  A  Case  Study  

Pipe  Break  Due  to  Relief  Valve  ChaEer  

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Engineering  Failures  –  Lessons  in  Professional  Ethics  –  A  Case  Study   Pipe  Break  Due  to  Relief  Valve  ChaEer  

Power Plant Bleed Condenser Pipe  break   occurred  at   elbow.    

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Engineering  Failures  –  Lessons  in  Professional  Ethics  –  A  Case  Study   Pipe  Break  Due  to  Relief  Valve  ChaEer   ²  What  happened  ?   ² Bleed  condenser  relief  valve  opens  and  cha6ers   causing  inlet  pipe  high  vibraDon.   ² Relief  valve  inlet  pipe  breaks  at  elbow  resulDng   in  a  small  reactor  loss  of  coolant  accident.   ² Operators  correctly  respond  to  cool  reactor  and   contain  spill  within  containment.   ² 4  reactors  shut  down  -­‐  3  for  3  months  pending   root  cause  invesDgaDon,  1  for  12  months  unDl   repairs  completed.  

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Engineering  Failures  –  Lessons  in  Professional  Ethics  –  A  Case  Study   Pipe  Break  Due  to  Relief  Valve  ChaEer   ²  What  errors  were  made  ?   ² Design  engineer  located  relief  valve  in  the   wrong  place  -­‐  too  close  to  reactor  face  for   periodic  tesDng  –  radiaDon  fields  too  high  there.   ² ConstrucDon  engineer  relocated  relief  valve  –   modified  installaDon  was  dynamically  unstable   –  asked  for  drawings  to  be  reissued  “as-­‐built”.   ² Design  engineer  did  not  check  as-­‐built  drawings   for  compliance  with  ASME  code’s  dynamic   stability  requirements  –  assumed  construcDon   engineer  had  done  so.  

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Engineering  Failures  –  Lessons  in  Professional  Ethics  –  A  Case  Study   Pipe  Break  Due  to  Relief  Valve  ChaEer   ²  How  Did  the  Errors  Happen  ?   ² No  procedural  requirement  for  design  engineer   approval  of  construcDon  engineer’s  “as-­‐built”   changes.   ² ConstrucDon  engineer  not  familiar  with  ASME   code  requirements  for  relief  valve  dynamic     stability.   ² Inadequate  supervisory  review  of  ASME  Boiler   and  Pressure  Vessel  Code  -­‐  SecDon  III  design   changes.  

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Engineering  Failures  –  Lessons  in  Professional  Ethics  –  A  Case  Study   Pipe  Break  Due  to  Relief  Valve  ChaEer   ²  What  are  the  Ethical  Issues  Involved  ?   ² ConstrucDon  engineer  performed  design  work   he/she  was  not  qualified  to  do  and  did  not   consult  qualified  engineer.   ² Design  engineer  did  not  retain  design   responsibility  for  his/her  own  system  –  reissued   but  did  not  check  as-­‐built  drawing.   ² IneffecDve  supervisory  review  and  approval  of   safety  criDcal  engineering  work.  

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Engineering  Failures  –  Lessons  in  Professional  Ethics  –  A  Case  Study   Pipe  Break  Due  to  Relief  Valve  ChaEer   ²  What  were  the  safety  and  economic  impacts  of  the   errors  ?   ² Fortunately  no  one  was  hurt.   ² Fortunately  no  radiaDon  was  released  to  the   environment  –  the  spill  was  in  the  reactor  building   which  is  part  of  the  radiological  containment   structures.   ² The  total  repair  and  replacement  power  costs  for  the   4  unit  outages  was  of  the  order  of  $100,000,000.  

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Engineering  Failures  –  Lessons  in  Professional  Ethics  –  A  Case  Study   Summary  of  Ethical  Lessons  for  Engineers

 

² Engineers  should  only  do  independent  work  where  they  are   fully  competent  to  do  so.   ² Engineers  who  are  not  yet  fully  competent  should  get  help   from  more  experienced  engineers  who  are  competent  in  the   work  that  is  being  done.   ² Engineers  should  review  changes  made  to  their  work  by   others  and  confirm  all  codes  and  standards  have  been  met.   ² Supervising  engineers  must  ensure  effecDve  independent   review  of  safety  criDcal  engineering  work  either  directly  or   by  commissioning  a  competent  senior  engineer  to  do  the   independent  review.  

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Engineering  Failures  –  Lessons  in  Professional  Ethics  –  A  Case  Study   Unexpected  Technical  Lessons  for  Engineers

 

²  During  the  accident  invesDgaDon  and  the  associated  computer   modeling,  simulaDon  studies  and  laboratory  validaDon  tesDng  we   discovered  two  important  design  aspects  of  safety  valves  that   manufacturers  and  uDliDes  were  not  aware  of.   ²  Safety  relief  valves  that  have  to  handle  2-­‐phase  flow  (eg:  liquid  and   vapour  in  equilibrium)  may  NOT  have  a  tradiDonal  safety  valve   characterisDc  and  can  fail  to  re-­‐close  at  the  reset  pressure  –  this  was   an  important  discovery  for  toxic,  flammable  and  radioacDve  fluids.     Laboratory  tesDng  at  the  idenDcal  plant  condiDons  is  essenDal  if  valve   re-­‐closure  at  the  reset  pressure  is  a  safety  requirement  !   ²  Safety  relief  valves  cycle  safely  rather  than  cha6er  destrucDvely  if  the   natural  frequency  of  the  valves  and  the  hydraulic  natural  frequency  of   the  piping  are  sufficiently  separated  –  this  is  the  criDcal  factor  to   prevent  cha6er,  NOT  the  distance  between  the  safety  relief  valve  and   the  vessel  that  the  valve  protects  !  

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Engineering  Failures  –  Lessons  in  Professional  Ethics  –  A  Case  Study   Unexpected  Technical  Lessons  for  Engineers

 

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Engineering  Failures  –  Lessons  in  Professional  Ethics  –  A  Case  Study  

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