COMMISSION STAFF WORKING DOCUMENT Technical summary on the implementation of comprehensive risk and safety assessments of nuclear power plants in the European Union Accompanying the document COMMUNICATION FROM THE COMMISSION TO THE COUNCIL AND THE EUROPEAN PARLIAMENT on the comprehensive risk and safety assessments ("stress tests") of nuclear power plants in the European Union and related activities
Date: 2012-10-04
Institutions: European Commission
Subjects: nuclear law, nuclear power station, nuclear safety

EUROPEAN 
COMMISSION 

Brussels, 4.10.2012  
SWD(2012) 287 final 

COMMISSION STAFF WORKING DOCUMENT 

Technical summary on the implementation of comprehensive risk and safety 
assessments of nuclear power plants in the European Union 

Accompanying the document 

COMMUNICATION FROM THE COMMISSION TO THE COUNCIL AND THE 
EUROPEAN PARLIAMENT 

on the comprehensive risk and safety assessments ("stress tests") of nuclear power 
plants in the European Union and related activities 

{COM(2012) 571 final} 

EN 

   EN 

 
 
 
 
  
 
TABLE OF CONTENTS 

1. 

THE EU NUCLEAR STRESS TESTS: APPROACH AND METHODOLOGY ........................ 4 

1.1. 

The peer review process............................................................................................. 4 

2. 

2.1. 

2.2. 

2.3. 

2.4. 

3. 

4. 

4.1. 

4.2. 

4.3. 

5. 

5.1. 

5.2. 

5.3. 

5.4. 

5.5. 

5.6. 

5.7. 

5.8. 

5.9. 

KEY RECOMMENDATIONS FROM THE SAFETY ASSESSMENTS..................................... 5 

Specific recommendations on external hazards ...................................................... 5 

Specific recommendations on loss of safety functions ............................................ 6 

Specific recommendations on severe accident management.................................. 6 

Aircraft crashes .......................................................................................................... 6 

KEY RECOMMENDATIONS FROM THE SECURITY ASSESSMENTS................................. 7 

MORE DETAILED TRANSVERSAL AND GENERIC RESULTS OF THE SAFETY 
ASSESSMENTS ............................................................................................................... 7 

Initiating events .......................................................................................................... 7 

Loss of safety functions............................................................................................ 10 

Severe Accident Management................................................................................. 12 

SUMMARIES OF MEMBER STATE STRESS TEST PEER REVIEW RESULTS ................ 16 

BELGIUM ................................................................................................................ 16 

BULGARIA .............................................................................................................. 18 

CZECH REPUBLIC................................................................................................ 19 

FINLAND.................................................................................................................. 21 

FRANCE ................................................................................................................... 23 

GERMANY............................................................................................................... 25 

HUNGARY ............................................................................................................... 26 

LITHUANIA............................................................................................................. 28 

THE NETHERLANDS............................................................................................ 29 

5.10.  ROMANIA................................................................................................................ 31 

5.11. 

SLOVAKIA .............................................................................................................. 33 

5.12. 

SLOVENIA............................................................................................................... 34 

5.13. 

SPAIN........................................................................................................................ 36 

5.14. 

SWEDEN .................................................................................................................. 38 

2 

 
 
 
5.15.  UNITED KINGDOM............................................................................................... 39 

6. 

6.1. 

6.2. 

SUMMARIES OF NEIGHBOURING COUNTRIES' PEER REVIEWS................................ 42 

SWITZERLAND...................................................................................................... 42 

UKRAINE................................................................................................................. 44 

GLOSSARY............................................................................................................................ 47 

Annex 1: Summary Table...................................................................................................... 49 

3 

 
 
 
1. 

THE EU NUCLEAR STRESS TESTS: APPROACH AND METHODOLOGY 

The  stress  tests  were  conducted  according  to  a  common  methodology1  along  two 
parallel tracks: 

• 

• 

A  Safety  Track  to  assess  how  individual  nuclear  power  plants  can  withstand 
the consequences of various unexpected events, ranging from natural disasters 
to human error or technical failure and other accidental impacts.  

A  Security  Track  to  analyse  security  threats  and  a  methodology  for  the 
prevention of, and response to, incidents due to malevolent or terrorist acts. For 
the assessments under this second track, the Council set up the Ad-hoc Group 
on Nuclear Security (AHGNS).  

Specifications  on  the  safety  track  of  the  stress  tests  defined  three  main  areas  to  be 
assessed: extreme natural events (earthquake, flooding, extreme weather conditions), 
response of the plants to prolonged loss of electric power and/or loss of the ultimate 
heat sink (irrespective of the initiating cause) and severe accident management.  

• 

• 

• 

• 

The safety assessments were organised in three phases: 

Self assessments by nuclear operators. Nuclear licensees were asked to produce 
reports to national regulators by 31 October 2011; 

Review  of  the  self  assessments  by  national  regulators.  National  regulators 
reviewed  the  information  supplied  by  licensees  and  prepared  national  reports 
by 31 December 2011; 

Peer  reviews  of  the  national  reports,  conducted  in  the  period  January  –  April 
2012. 

All national reports were submitted to the Commission within the agreed deadline.  

1.1. 

The peer review process 

In order to provide an objective assessment of the work done at national level and to 
maximise coherence and comparability, the national reports were subjected to a peer 
review process, organised in three phases: 

– 

A desktop review phase where the 17 national reports were analysed by all the 
peer reviewers2, who posed more than 2 000 written questions on the reports. 
The  EU  Stress  Test  secretariat  run  by  the  Joint  Research  Centre  of  the 
Commission  opened  a  dedicated  website  to  gather  questions  from  the  public 
for the peer reviews. 

1 
2 

ENSREG specifications agreed in May 2011, see www.ensreg.eu  
January 2012 

4 

 
 
 
                                                            
– 

– 

A  peer  review  related  to  horizontal  topics,  comparing  the  consistency  of  the 
national  approaches  and  findings  in  three  key  areas:  extreme  natural  events, 
loss  of  safety  functions  and  severe  accident  management.  The  topical  review 
meetings  were  organised  at  the  Commission  premises  in  February  2012,  and 
involved around 90 experts. National teams were called in and asked to answer 
the questions posed in the desktop review phase. The result is summarised in 3 
topical reports and 17 country reports for each participating country, with a list 
of remaining open questions for the ensuing country peer reviews.  

A  vertical,  individual  review  of  each  of  the  17  country  reports.  The  country 
peer reviews took place in March 2012 and included one NPP site visit in each 
country.  As  a  result,  the  country  reports  were  finalised,  providing  the  basis  – 
together with the topical reports – for the overall peer review Board report to 
ENSREG, which endorsed it on 26 April 20123. 

The  peer  review  teams  were  composed  of nuclear  safety  experts  from  EU  Member 
States,  Switzerland,  Ukraine  and  from  the  Commission,  with  observers  from  third 
countries (Croatia, USA, Japan) and the IAEA4. 

– 

A  considerable  effort  was  made,  in  terms  of  human  resources,  to  analyse  the 
safety of all NPPs and spent fuel storage facilities of all 17 countries in a short 
time. In  each of the  17 countries  the  review team has conducted a NPP visit. 
The  total  number  of  reactor  units  on  the  sites  visited  during  the  originally 
scheduled visits in March 2012 was 43 (approximately 30% of all the units in 
operation).  The  plant  visits  confirmed  the  prior  analyses  and  in  some  cases 
have led to additional recommendations. 

Additional  visits  were  performed  to  eight  reactor  sites  by  the  peer  review  teams  in 
September  2012,  in  order  to  gain  additional  insight  on  different  reactor  types,  to 
discuss  implementation  of  the  identified  improvements  and  in  order  to  alleviate 
concerns  relating  to  installations  in  areas  bordering  other  Member  States.  Thus,  all 
operating reactor types in Europe have been visited by peer reviewers. 

All reports, including the licensee reports have been made available on the ENSREG 
website. 

2. 

KEY RECOMMENDATIONS FROM THE SAFETY ASSESSMENTS 

The key considerations for each topic are summarised in the following sections. 

2.1. 

Specific recommendations on external hazards 

• 

The  technical  design  and  operation  of  plant  must  be  able  to  deal  with 
unforeseen  external  hazards  (e.g.  earthquake,  flooding,  extreme  weather  and 
accidents) and external events, unexpected events which were not planned for 
in the original design (beyond design margins).   

3 
4 

http://www.ensreg.eu/sites/default/files/ENSREG%20Action%20plan.pdf  
http://www.ensreg.eu/sites/default/files/Peer%20Review%20Topical%20Teams.pdf  
http://ensreg.com/sites/default/files/Country%20Review%20Teams.pdf  

5 

 
 
                                                            
• 

• 

On-site seismic instrumentation should be in operation at each NPP.  

As  a  good  practice,  the  use  of  a  ‘hardened  core’  of  safety-related  systems, 
structures  and  components  capable  of  withstanding  earthquakes  and  flooding 
significantly beyond design basis should be considered.  

2.2. 

Specific recommendations on loss of safety functions 

This depends on the specific reactor design, but in terms of safety margins, Station 
Black-Out (SBO, i.e. total loss of AC power), which can lead to core heat-up within 
30-40  minutes,  depending  on  the  reactor  design,  is  the  key  risk.  Therefore,  the 
following should be readily available under even the most extreme conditions: 

• 

• 

• 

a variety of mobile devices (such as mobile generators, mobile pumps, mobile 
battery  chargers  or  mobile  DC  power  sources,  fire-fighting  equipment, 
emergency lighting, etc.).  

the availability of alternative means of cooling;  

specialised  equipment  and  fully  trained  staff  to  deal  effectively  with  events 
affecting all the units on one site.  

2.3. 

Specific recommendations on severe accident management 

• 

• 

• 

• 

• 

Recognised  measures  to  protect  containment  integrity  should  be  urgently 
implemented. 

Comprehensive Severe Accident Management Guidelines (SAMG's) should be 
developed.  Periodic  validation  of  SAMG's  is  essential  for  ensuring  their 
practicability, robustness and reliability. 

SAM arrangements need to be enhanced, including the methods and tools for 
SAM  training,  and  exercises  should  include  the  suitability  of  equipment, 
instrumentation and communication means.  

On-site  emergency  centres  should  be  available  and  designed  against  impacts 
from extreme natural. 

Radiation  protection  of  all  staff  involved  in  severe  accident  management  and 
emergency response must be ensured.  

•  Where emergency equipment is stored centrally, it must be stored in locations 
that  are  safe  even  in  the  event  of  general  devastation,  and  where  it  can  be 
quickly supplied to the relevant NPP site. 

2.4. 

Aircraft crashes 

Aircraft  crashes  have  not  been  considered  explicitly  as  an  initiating  event  in  the 
safety  assessments.  However,  the  stress  tests  have  to  a  considerable  extent  covered 
the  indirect  effects  of  airplane  crashes  through  the  thorough  work  undertaken  on 
station blackout and loss of plant cooling.  

6 

 
 
The  national  reports  of  Belgium,  Germany,  Slovenia  and  the  Netherlands  mention 
that  the  scope  of  the  stress  test  has  been  extended  to  aircraft  crashes.  Further 
information on these countries is presented in the corresponding country sections. 

3. 

KEY RECOMMENDATIONS FROM THE SECURITY ASSESSMENTS

5 

The final report of the Ad Hoc Group on Nuclear Security6 presents conclusions on 
the  five  themes  discussed,  namely  physical  protection,  malevolent  aircraft  crashes, 
cyber-attacks,  nuclear  emergency  planning,  and  exercises  and  training.  It  also 
contains  several  recommendations  to  the  Member  States  in  order  to  strengthen 
nuclear security in the EU. It highlights in particular: 

• 

• 

• 

• 

the importance for the Member States which have not yet done so to complete 
the ratification of the amended Convention on Physical Protection of Nuclear 
Materials; 

the added value of IAEA's guidance and services, including IPPAS7 missions 
on a regular basis in all Member States having nuclear power plants; 

the importance of a regular and close cooperation between Member States and 
with neighbouring countries and 

the necessity to define modalities and fora for the continuation of EU work on 
nuclear security. 

4. 

MORE  DETAILED  TRANSVERSAL  AND  GENERIC  RESULTS  OF  THE  SAFETY 
ASSESSMENTS 

The  following  transversal  and  generic  issues  can  be  highlighted.  A  comprehensive 
description  of  the  situation  can  be  found  in  the  final  peer  review  report,  national 
reports and the peer review reports.  

4.1. 

Initiating events 

Stress test results clearly indicate that particular attention needs to be paid to periodic 
safety reviews as a powerful  tool to regularly reassess plant safety. The  stress tests 
have confirmed that all the 17 participating countries perform periodic safety reviews 
at  least  every  10  years,  including  a  reassessment  of  the  external  hazards  (currently 
unless it can be demonstrated that there was no significant hazard evolution since the 
last reassessment). External hazards (e.g. earthquake, flooding and extreme weather) 
and robustness of the plants against them should be reassessed as often as appropriate 
but at least every 10 years.  

5 
6 
7 

This section is based on the Final Report of the Council Ad-hoc Group on Nuclear Security (AHGNS). 
http://register.consilium.europa.eu/pdf/en/12/st10/st10616.en12.pdf, 31.5.2012. 
International Physical Protection Advisory Service. 

7 

 
 
 
                                                            
Generally  the  approach  to  demonstrate  an  appropriate  design  basis  is  sound.  All 
plants need to be reviewed with respect to external hazard safety cases corresponding 
to  an  exceedance  probability  of  10-4  /  year  (with  a  minimum  peak  ground 
acceleration of 0.1 g for the seismic hazard).  Setting up an international benchmark 
exercise  to  evaluate  the  relative  strengths  and  weaknesses  of  probabilistic  and 
deterministic hazard assessment methods for external events is recommended. 

Almost  all  countries  consider  for  Design  Basis  Earthquakes  an  earthquake  with  an 
exceedance probability of 10-4 / year as a minimum. The Stress tests results point out 
nevertheless specific cases: 

– 

– 

In  France,  no  probabilistic  seismic  hazard  assessment  (PSHA)  is  used  except 
for  3  plants  (Saint-Alban,  Flamanville  and  Civaux).  The  peer-review 
recommended  to  the  regulator  to  introduce  Probabilistic  Seismic  Hazard 
Analysis in France for the design basis of new reactors and for future revisions 
of the seismic design basis of existing reactors in order to provide information 
on event probability (annual frequency of occurrence) and to establish a more 
robust basis for DBE specifications. 

In Romania, analyses showed that the exceedance probability associated to the 
DBE was 10-3 / year. The Design Basis is considered to be consistent with the 
minimum  levels  in  international  standards  but  not  with  current  practices  in 
Europe.  Margins  have  however  been  demonstrated  beyond  the  Design  Basis, 
using  a  review  level  earthquake  (RLE)  with  a  PGA  of  0,33  g  and  upgrading 
this by a screening level of 0.4 g (corresponding to an exceedance probability 
of 5.10-5/year) for safety relevant Structures, Systems and Components on the 
safe shut down path.  

Almost  all  countries  consider  for  Design  Basis  Flood  a  flood  with  an  exceedance 
probability  of  10-4  /  year  as  a  minimum.  The  Stress  tests  results  point  out 
nevertheless specific cases: 

– 

– 

– 

In  Belgium,  the  Tihange  site  is  currently  protected  by  its  design  against  a 
reference  flood  with  a  statistical  return  period  up  to  400  years.  However,  the 
reference  flood  with  a  statistical  return  period  up  to  10,000  years  will  be 
implemented as a new DBF and associated protection measures are foreseen. 

the  design  basis  flood 

In  France, 
is  defined  considering  statistical 
extrapolations  limited  to  10-3  /  year  supplemented  by  a  margin  or  a 
conventional combination. France stated that the current state of the art in flood 
level calculations does not allow calculating, with a sufficient confidence, 10-4 
/  year  levels,  except  in  some  specific  conditions  such  as  "small  catchments 
areas  -  up  to  some  1000  km2".  The  Peer-review  therefore  recommended 
performing  a  comparative  evaluation  with  the  methodologies  used  in  other 
European countries. 

In  the  Netherlands,  the  Borssele  site  is  protected  against  flooding  by  the 
network  of  dykes  in  Zeeland.  This  network  will  be  improved  to  comply  with 
the  legal  requirements  of  4000  year  return  period.  The  reinforcements  will 
include  margins  in  order  to  guarantee  the  legal  safety  standard  also  in  the 
future. Therefore, the protection provided by the levee after the reinforcement 

8 

 
 
should  be  higher  (against  events  with  a  return  period  of  10,000  years).  
the 
However, 
consistency of this approach with the new IAEA guidance (SSG-18). 

recommended  examining 

the  Peer-Review 

thoroughly 

Almost all countries consider 0.1 g as the minimal level of PGA to be considered for 
the  Design  Basis  Earthquake,  except  Germany,  Lithuania  and  the  Netherlands.  It 
should  be  mentioned  however  that  the  nuclear  reactors  have  been  shut  down  in 
Lithuania and that the existing and new spent fuel store facilities are designed to be 
capable of withstanding this recommended level of seismic event. Moreover, as for 
the  Netherlands,  the  new  seismic  analysis  to  be  conducted  within  the  PSR  of 
Borssele in 2012 will consider a PGA value of 0.1g at free field for the DBE, as per 
IAEA guidance. 

The  evaluation  of beyond design basis margins  for earthquakes  and  flooding  is not 
consistent  in  participating  countries.  A  few  countries  have  quantified  the  inherent 
robustness of the plants' beyond the design basis up to cliff edge effects, whereas the 
majority  have  made  only  a  general  claim  that  sufficient  safety  margins  exist  and 
therefore there is no verifiable information on the basis of which to consider effective 
potential improvements.  

A  number  of  possible  means  to  increase  the  robustness  of  NPPs  against  external 
hazards has been identified during the stress tests. Among these, the following can be 
mentioned: 

– 

– 

the protected volume approach (flood protection of building containing safety 
significant  systems  and  components),  used  at  least  to  some  extent  in  CH,  FR 
and NL. 

the  use  of  a  bunkered  or  ‘hardened  core’  of  safety-related  systems,  structures 
and  components  capable  of  withstanding  earthquakes  and 
flooding 
significantly  beyond  design  basis  can  be  mentioned.  This  is  currently  used 
namely in BE, CH, Finland (only for Loviisa) and DE, planned to some extent 
in SI and requested to be implemented in FR.  

Additional guidance on natural hazards assessments, including earthquake, flooding 
and  extreme  weather  conditions  should  be  developed,  as  well  as  corresponding 
guidance  on  the  assessment  of  margins  beyond  the  design  basis  and  cliff-edge 
effects.  

Regulators and operators should consider developing standards to  address  qualified 
plant  walk-downs  with  regards  to  earthquake,  flooding  and  extreme  weather  to 
provide  a  more  systematic  search  for  non-conformities  and  correct  them  (e.g. 
appropriate  storage  of  equipment,  particularly  for  temporary  and  mobile  plant  and 
tools used to mitigate BDB external events). 

The  design  for  storage  of  mobile  equipment  to  perform  necessary  safety  functions 
should  take  account  of  external  events  at  the  design  and  beyond  design  levels,  to 
ensure appropriate availability in the event of being required following a significant 
external event. 

9 

 
 
The  Peer-Review  observed  namely  that  mobile  diesel  generators  should  be 
adequately protected for beyond design basis earthquake in Kozloduy (BG). Similar 
observations  were  made  in  the  Czech  Republic  and  in  Slovakia  where  the  fire 
brigade buildings should be reinforced to withstand BDBE. Moreover, it was noted 
in the Netherlands that storage facilities for portable equipment, tools and materials 
needed  by  the  alarm  response  organization  that  are  accessible  after  all  foreseeable 
hazards would enlarge the possibilities of the alarm response organization. 

Seismic  monitoring  systems  should  be  installed  and  associated  procedures  and 
training developed for those NPPs that currently do not have such systems. On-site 
seismic  instrumentation  should  be  in  operation  at  each  NPP.  Currently,  there  is  no 
on-site seismic instrumentation yet in Dukovany NPP (CZ), Brokdorf, Brunsbuettel, 
Emsland,  Grohnde,  Kruemmel  and  Unterweser  NPPs  (D),  Borssele  NPP  (NL), 
Oskarshamn NPP (SE) and in all Ukrainian NPPs. The installation of on-site seismic 
monitoring is planned in each of these sites. A study to investigate the overall cost-
induced  by  seismic 
benefit  and  usefulness  of  automatic  reactor  shutdown 
instrumentation is recommended. 

Advance  warning  of  deteriorating  weather  is  often  available  in  sufficient  time  to 
provide  the  operators  with  useful  advice  and  national  regulators  should  ensure  that 
appropriate  communications  and  procedures  are  developed  by  all  operators.  In 
Sweden in particular, the Peer Review recommended that early warning systems, as 
well as relevant operating procedures in case of extreme weather conditions, should 
be implemented at all sites. 

4.2. 

Loss of safety functions 

All the countries estimated the cliff-edge effects related to various combinations of 
losses of electrical power and/or cooling water, and the time available before safety 
functions need to be restored. In terms of safety margins, Station Black-Out (SBO, 
i.e. total loss of AC power) is the limiting  case for most reactors.  For most  reactor 
designs,  SBO  would  typically  lead  to  core  heat-up  after  around  1-10  hours  if  no 
countermeasures  were  implemented.  For  some  Boiling  Water  Reactor  (BWR) 
designs  SBO  leads  to  core  heat-up  within  30-40  minutes  (using  conservative 
assumptions)  at  Olkiluoto  1  &  2,  (FI)  and  Forsmark  1  &  2  (SE),  which  have  their 
core cooling systems electrical driven, if no countermeasures are adopted. Numerous 
improvements  related  to  hardware  and  procedures  have  been  identified;  some  have 
been  implemented  and  others  are  still  at  the  planning  stage.  It  is  recommended  to 
ensure  in  all  plants  that  the  time  available  is  sufficient  to  allow  safety  function 
restoration, with adequate margin and not relying on organisational measures only.  

The loss of Ultimate Heat Sink (UHS) and alternate heat sink was not identified as a 
cliff edge effect at any plant design in EU, CH and UA. NPPs typically have several 
redundant and diverse cooling options to ensure a minimum heat sink for 72 hours, 
provided  that  electrical  power  supply  is  available.  The  volume  of  cooling  water 
available on site that ensures heat removal from essential consumers is not less than 
6-8 days. 

To  increase  the  robustness  of  the  ultimate  heat  sink  function,  it  is  strongly 
recommended to identify and implement also alternative means of cooling. The term 
“alternate  UHS”  was  interpreted  differently  in  several  countries.  Most  countries 

10 

 
 
considered  a  diverse  source  of  cooling  medium  (water  from  ponds,  wells,  water 
table,  etc.)  as  an  alternate  UHS,  but  some  countries  also  considered  secondary  or 
primary feed-and-bleed into (ultimately) the atmosphere. To cope with losses of the 
main ultimate heat sink, all plants have a variety of design features that can be used 
to  some  extent;  this  includes  multiple  (and  large)  reserves  of  water  on  site  e.g. 
dedicated  tanks  (seismic  proof),  large  capacity  pools  (e.g.  with  spray-based  heat 
removal  from  essential  service  water  system),  dedicated  wells  (with  own, 
independently powered pumps) as well as arrangements to obtain water from rivers, 
nearby lakes or the sea (using tank trucks or fire hoses). 

For  multi-unit  sites,  robustness  could  be  enhanced  if  additional  equipment  and 
trained staff are available to effectively deal with events affecting all the units on one 
site.  At  most  multi-unit  sites,  an  accident  simultaneously  occurring  at  several  units 
was  not  considered  in  the  original  design.  For  multi-unit  sites,  robustness  could  be 
enhanced  if additional (to  the existing) equipment and trained  staff are  available to 
effectively deal with events affecting all the units on one site. This recommendation 
is currently analysed and measures will be implemented at all NPP sites in EU, CH 
and UA. 

All  plants  confirmed  that  they  already  possess  or  are  in  advanced  process  of 
acquiring  a  variety  of  mobile  devices  including  skid/trailer  based  diesel  generators 
and diesel-driven pumps, dedicated fire trucks, etc. including the connection points 
and procedures on how to engage mobile units. Nevertheless, a systematic selection 
of  and  acquisition  of  the  equipment  that  would  provide  a  variety  of  power  and 
pressure levels and that is safely stored on-site and/or offsite still needs to be done. 
The  transport,  simple  and  fast  connection  of  the  mobile  equipment  including  its 
proper functioning (considering fuel supply, independence but also organization and 
procedures) shall be assured by appropriate, plant and site centric design and regular 
testing  after  installation.  Mobile  battery  chargers  or  mobile  DC  power  sources  are 
already  installed  at  Cernavoda  NPP  (RO),  Kozloduy  NPP  (BG),  and  Loviisa  NPP 
(FI)  and  ensure  DC  power  for  SBO  consumers  by  recharging  station  batteries  via 
small diesel generators, or even back-up station batteries have been installed at Paks 
NPP  (HU)  which  allow  extended  use  of  instrumentation  and  controls.  Fire-fighting 
equipment, including fire trucks, diesel pumps,  generators, emergency lighting, etc. 
is normally readily available at the plants. 

Operational or preparatory actions such as ensuring the supply of fuel and lubrication 
oil,  battery  load-shedding  to  extend  battery  life  are  examples  of  measures  that  are 
small  (in  many  cases  procedural)  but  that  could  make  a  considerable  difference  in 
response  to  initiators.  All  in  all,  most  of  the  plants  have  already  considered  these 
measures and might be adding to them in the future. 

Within  the  stress  tests  evaluation  the  bunkered  system,  qualified  to  anticipated 
external  events,  are  equipped  with  independent  diesel  driven  pumps  and  water 
storage to ensure heat sink, and electrical power supply to vital consumers via stand-
by small emergency diesel generators, batteries, and diesel-driven pumps for at least 
24  hours.  Bunkered  systems  are  already  installed  as  a  standard  design  feature  at 
German pre-Konvoi and Konvoi NPP design (i.e. in all plants operating these reactor 
design in DE, NL, and ES), as well as in all NPPs in CH and with some degree also 
at NPPs in BE. Bunkered system proved its worth in ensuring an additional level of 

11 

 
 
protection after the external events, able to cope with a variety of initiators, including 
those beyond the design basis. It provides back up to ordinary stand by systems (e.g. 
emergency diesel generators) to ensure fulfilment of safety functions even if all stand 
by safety related equipment is lost. The concept is taken even further in the form of 
the  "hardened  core"  where  in  addition  to  equipment,  trained  staff  and  procedures 
designed to cope with a wide variety of extreme events will be available. 

4.3. 

Severe Accident Management 

PSR  should  continue  to  be  maintained  as  a  powerful  regulatory  instrument  for  the 
continuous enhancement of defence-in-depth in general, and the provisions of SAM 
in  particular.  The  lessons  learned  from  the  Fukushima  accident  and  from  the  stress 
tests should be reflected in the scope of future PSRs. 

In  response  to  their  previous  commitments,  regulators  should  incorporate  the 
WENRA reference levels related to SAM into their national legal  frameworks,  and 
ensure  their  implementation  as  soon  as  possible.  Regarding  Emergency  Operating 
Procedures (EOPs) and Severe Accident Management Guidelines (SAMGs), utilities 
from only a few countries have developed these procedures/guidelines for all power 
conditions  (Belgium,  Slovenia,  Sweden,  the  Netherlands,  France  for  the  900  MWe 
reactor series, and Switzerland). In Hungary, EOPs and SAMGs are developed for all 
plant states but the associated hardware modifications are still needed in units 2 to 4 
to complete implementation. In most of the other countries, utilities have developed 
EOPs  for  power  and  shutdown  states  but  SAMGs  cover  only  power  state  (e.g.  in 
Bulgaria  and  Czech  Republic).  In  a  few  countries  like  Germany  or  Spain  the 
development of a more comprehensive and systematic set of SAMGs is still on-going 
for some Plants. Ukraine has only EOPs for power states available at the moment but 
is  engaged  in  a  program  to  complete  EOPs  for  shutdown  states  and  to  develop 
SAMGs  for  all  power  states.  In  the  UK,  it  appears  that  EOPs  and  SAMGs  need 
further development to be in line with international Standards.  

Effective implementation of SAM requires that adequate hardware provisions are in 
place to perform the selected strategies.  

On top of RCS depressurisation systems, Passive Autocatalytic Recombiners (PARs) 
and  containment  Filtered  Venting  System  discussed  separately,  several  other 
hardware  provisions  are  already  installed  or  will  be  installed  in  the  different  NPPs 
concerned by this review. The main ones are listed below: 

– 

Additional  Diesel  Generators  (or  Combustion  Turbines)  physically  separated 
from the normal DGs and devoted to cope with SBO, external events or severe 
accident situations are already installed on the different NPPs in Germany, the 
Netherlands,  Belgium,  Finland,  Hungary,  Romania,  Spain,  UK,  France  and 
Switzerland.  

–  Mobile  equipment  especially  Diesels  Generators  are  already  available  on  the 
different  NPPs 
in  many  countries,  such  as  Belgium,  Lithuania,  The 
Netherlands,  Romania,  Bulgaria,  Slovenia,  Hungary  or  are  under 
implementation in many others such as Slovakia, and Czech Republic.  

12 

 
 
– 

– 

In  some  countries,  centralised  storage  of  emergency  equipment  has  been  set-
up,  shared  among  several  NPP  sites.  This  is  for  example  the  case  in  the  UK, 
DE and CH. And this will be implemented in Spain and in France (as part of 
the Rapid Action Force which will be put in place). The regulatory Body from 
Czech Republic has also proposed to establish common (regional) emergency 
response arrangements for neighbour countries operating similar reactors. 

In  most  of  the  countries  the  instrumentation  and  communication  means  have 
been qualified for Design Basis Accidents but further investigations are needed 
to  ensure  the  availability  of  these  equipment  during  a  Severe  Accident 
especially concerning power supply and survivability under external events and 
harsh conditions. 

The  means  for  maintaining  containment  integrity  should  in  particular  include 
depressurization  of  the  reactor  coolant  system,  prevention  of  damaging  hydrogen 
explosions,  and  means  of  addressing  long-term  containment  over-pressurization, 
such as filtered venting. 

All  plants  foresee  the  depressurization  of  the  primary  circuit  with  existing  design 
features.  For  example,  Czech  Republic,  France  and  Finland  have  implemented 
additional measures for depressurization of the primary system, such as installation 
of  additional  hardware  (lines  and  specific  valves).  Slovakia 
is  currently 
implementing,  and  Slovenia  has  scheduled  implementing  similar  measures.  France 
has  planned  the  reinforcement  of  the  operability  of  existing  equipment  by  fixed  or 
mobile supplies.  

Most  of  the  plants  have  measures  to  prevent  hydrogen  explosions  in  place.  Older 
operating BWR plants in Switzerland (Mühleberg), Germany, Spain (Santa María de 
Garoña), Finland (Olkiluoto 1 and 2), and Sweden (Oskarshamn 1, 2 and 3, Forsmark 
1,  2  and  3,  and  Ringhals  1),  and  Cernavoda  1  CANDU  (Romania)  have  their 
containments  inerted  with  nitrogen.  Newer,  larger  BWR  plants  like  Leibstadt 
(Switzerland)  and  Cofrentes  (Spain),  and  Cernavoda  2  CANDU  (Romania)  have 
ignitors.  Of  these,  only  the  Gundremmingen  B  and  C  have  additionally  Passive 
Autocatalytic  Recombiners  (PAR), although Santa María  de Garoña, Cofrentes and 
Cernavoda  (both  units)  have  plans  to  install  them,  and  Leibstadt  is  evaluating  long 
term  hydrogen  management.  Most  of 
light  water  reactor 
containments  have  reinforced  the  measures  to  prevent  hydrogen  explosions  during 
accidents  by  the  installation  of  Passive  Catalytic  Recombiners  (PAR).  The  PARs 
installed  in  Bulgaria,  Czech  Republic,  Slovenia,  United  Kingdom  (Sizewell  B)  and 
Ukraine (Rivne and Khmelnitsky) were designed for DBA, and have not been proven 
to  mitigate  hydrogen  explosion  risks  in  severe  accidents.  Studies  or  plans  to  install 
additional PAR as needed to cope with hydrogen risks in severe accidents are under 
way in these countries. The countries that have not installed PAR in all their PWR 
plants:  Spain,  (PARs  only  in  Trillo),  and  Ukraine,  have  also  plans  to  install  them. 
The rest of the PWR plants have PAR capable of coping with the risk of hydrogen 
generation during severe accidents. Although it has been recognized that the risk of 
hydrogen  explosions  in the  UK  gas  cooled  reactors  is  not  a  sensitive  issue,  further 
studies regarding generation of combustible gases are under way.   

the  non-inerted 

13 

 
 
Hungary,  Slovakia  and  Ukraine  do  not  have  any  plan  or  schedule  with  regard  to 
implementing filtered venting of the containment. Czech Republic, Spain and United 
Kingdom are in different stages of the process of considering the implementation of 
containment  filtered  venting,  Belgium  has  included  it  in  the  long  term  operation 
project for its older plants (Doel 1 and 2, and Tihange 1), and studying its installation 
in  the  newer  plants,  while  Romania  has  a  schedule  to  implement  it.  The  remaining 
countries  have  already  filtered  venting  infrastructure  installed  to  avoid  pressure 
build-up in the containment. 

A  systematic  review  of  SAM  provisions  should  be  performed,  focusing  on  the 
availability  and  appropriate  operation  of  plant  equipment 
the  relevant 
circumstances,  taking  account  of  accident  initiating  events,  in  particular  extreme 
external hazards and the potential harsh working environment.  

in 

In  the  frame  of  this  Stress  Tests  exercise,  a  systematic  review  of  SAM  provisions 
(organization, staffing, hardware, SAMGs, etc.) has been performed by the different 
participants,  focusing  on  the  availability  and  appropriate  operation  of  plant 
equipment in the relevant circumstances, taking account of accident initiating events, 
in particular extreme external hazards, potential harsh working environment, need to 
work  with  a  severely  damaged  infrastructure  (i.e.  in  which  the  usual  means  of 
communication  and  access,  etc.  are  disabled),  at  plant  level,  corporate-level  and 
national-level aspects, and of long-duration accidents affecting multiple units at the 
same time (on individual and nearby sites as appropriate). These studies are still on-
going  in  most  of  the  countries  to  finalize  the  most  adequate  SAM  provisions  to  be 
put in place. 

The assessment of SAM provisions should take account of the need to work with a 
severely damaged infrastructure (i.e. in which the usual means of communication and 
access,  etc.  are  disabled),  of  plant  level,  corporate-level  and  national-level  aspects, 
and  of  long-duration  accidents  affecting  multiple  units  at  the  same  time  (on 
individual and nearby sites as appropriate). 

The  SAMGs  should  be  comprehensively  validated  taking  due  account  of  the 
potential  long  duration  of  the  accident,  the  degraded  plant  and  the  surrounding 
conditions. All countries that have developed SAMG have validated them in terms of 
feasibility of the potential strategies, but it is not clear in all cases that the validation 
has considered explicitly the potential long duration of the accident and the existence 
of degraded conditions. In such cases, the countries have declared their intention of 
extending  the  validation  of  the  SAMG  with  the  inclusion  of  the  potential  long 
duration of the accident, and the presence of degraded conditions (for example due to 
extreme external hazards). Pre-planned SAM actions should be designed to function 
effectively and robustly for suitably lengthy periods following the initiating event. In 
most  cases,  durations  of  at  least  several  days  should  be  assumed  for  planning  and 
assessment purposes. 

Training  and  exercises  aimed  at  checking  the  adequacy  of  SAM  procedures  and 
organisational measures should include testing of extended aspects such as the need 
for corporate and national level coordinated arrangements and long-duration events. 
All  countries  that  have  implemented  the  SAMG  carry  out  periodic  training  and 
exercises to check the adequacy of SAM procedures and the adequate co-ordination 

14 

 
 
among  the  involved  organizations.  The  level  of  detail  and  scope  of  this  training  is 
diverse  among  the  participating  countries,  and  all  plan  to  enhance  it  to  take  into 
consideration  the  improvements  of  the  SAM  strategies  and  of  the  Emergency 
Organisations.  It  is  worth  mentioning  as  good  practice  the  very  complex  exercise 
organized  by  NL,  which  includes  all  involved  emergency  organizations,  with  more 
than  1000  participants,  and  the  real  time  SAM  drills  with  simulator  carried  out  by 
Slovenia, which can take several days. 

When developing SAM action plans, conceptual solutions for post-accident fixing of 
contamination and the treatment of potentially large volumes of contaminated water 
should be addressed. 

Radiation  protection  of  operators  and  all  other  staff  involved  in  the  SAM  and 
emergency  arrangements  should  be  assessed  and  then  ensured  by  adequate 
monitoring,  guaranteed  habitability  of  the  facilities  (hardened  on-site  emergency 
response facility with radiation protection) needed for accident control, and suitable 
availability of protective equipment and training. 

On-site  emergency  centres  should  be  available  and  designed  against  impacts  from 
extreme natural and radiological hazards. 

Main Control Rooms (MCR) of the plants have been designed against Design Basis 
Accidents. In case the Main Control Room becomes inhabitable as a consequence of 
the radiological releases of a severe accident, of fire in the MCR or due to extreme 
external  hazards, all  plants have a backup  Emergency Control  Room  (ECR)  except 
OL1&2 in Finland (where planning is underway to develop such a facility) and the 
AGRs and Magnox reactors in UK (except Heysham 2 and Torness). The countries 
have  evaluated  or  are  evaluating  whether  the  MCR  and  ECR  can  withstand  the 
consequences  of  a  severe  accident  (especially  in  case  of  accident  affecting  several 
units  at  the  same  time)  and  extreme  natural  hazards.  Most  of  the  countries  have 
already proposed additional measures to improve MCR and ECR habitability in case 
of severe accidents. 

Additionally,  some  plants  have  on-site  emergency  control  centres  from  which  the 
emergency response activities can be co-ordinated in case of Severe Accident. As an 
example,  the  emergency  control  centres  of  all  the  plants  in  Finland  (only  Loviisa 
site),  Germany,  Hungary,  Sweden,  Slovenia,  Lithuania,  Bulgaria  and  Ukraine  are 
well  prepared  against  radiological  and  extreme  natural  hazards.  The  rest  of  the 
countries have found out that their on-site emergency centres of facilities from which 
the emergency activities are coordinated need to be improved to withstand extreme 
external  hazards  or  radiological  conditions.  All  of  these  countries  plan  to  reinforce 
their existing on-site emergency centres, or to build new ones. 

Although  PSA  is  an  essential  tool  for  screening  and  prioritizing  improvements  and 
for assessing the completeness of SAM implementation, low numerical risk estimates 
should not be used as the basis for excluding scenarios from consideration of SAM 
especially if the consequences are very high. 

15 

 
 
5. 

SUMMARIES OF MEMBER STATE STRESS TEST PEER REVIEW RESULTS 

Note: a more comprehensive description of the situation can be found in the national reports 
and the peer review reports. 

5.1. 

BELGIUM  

Note:  Stress  tests  in  Belgium  cover  also  nuclear  facilities  other  than  operating  NPPs  (fuel 
fabrication  plant,  waste  treatment  and  storage  facilities,  radioisotope  production  facility, 
research centres), and include man-made events (terrorist attacks, aircraft crash, cyber-attack, 
toxic and explosive gases, blast waves) and security related aspects. The assessment of these 
man-made events was however developed in a separate national report which was not part of 
the peer review exercise. 

Recommendations:  

− 

It is recommended that the regulator monitors the completion of the updated probabilistic 
seismic  hazard  analysis  (PSHA),  the  implementation  of  the  consequential  measures  and 
the  updated  assessment  of  safety  margins.  These  updates  may  benefit  from  a 
harmonization  of  the  seismic  hazard  assessment  on  an  international  level  with 
neighbouring countries, in order to avoid discrepancies for sites with comparable seismic 
activity. 

−  Taking  into  account  the  relatively  low  safety  margins  with  regards  to  flooding  over  a 
period of 10 000 years and the reconsideration of design basis flood (DBF) values at the 
Tihange  site,  it  is  recommended  to  focus  on  the  implementation  of  all  safety 
improvements proposed by the licensee, as well as those prescribed by the regulator. For 
the  Doel  site,  it  is  recommended  to  the  regulator  to  monitor  the  implementation  of  the 
measures proposed in the licensee’s action plan.  

−  The design parameters for extreme weather conditions are mainly based on historical data, 
and therefore, on a return period in the order of 100 years. The derivation of design basis 
parameters with 10,000 years return periods is recommended to be considered.  Attention 
should be also paid to extreme temperatures. 

− 

In case of design basis earthquake (DBE), the autonomy of the emergency diesel generators 
(EDGs) of the 2nd level safety systems at the Tihange 1 is only 7.5 hours (the capacity of 
their seismically qualified fuel tanks is the limiting factor). It is recommended to take into 
consideration  the  benefits  of  increasing  the  autonomy  of  these  EDGs  at  Tihange  1  for 
events determined by DBE. 

−  The preliminary study for the filtered venting system on each unit to be finished in 2012 

should consider sub-atmospheric pressures in the containment. 

−  Regardless of the outcome of the assessment of the residual risk of hydrogen generation 
and  accumulation  in  the  spent  fuel  pool  (SFP)  buildings,  the  installation  of  Passive 
Autocatalytic Recombiners (PARs) in the SFP should be considered. 

−  The  additional  measures  to  increase  the  consistency  of  the  emergency  training  and 
refresher  training  programs  at  the  Tihange  and  Doel  NPPs  should  be  broadened  to  the 
total  concept  of  severe  accident  management  (SAM)  (hardware  provisions,  procedures 
and guidelines) as much as possible. 

Good practices: 

−  Multiple external power supply links (two independent power supplies). 

16 

 
 
−  Underground  cable  6.6  kV  lines  (after  transformers)  linking  150  kV  on-site  sub-stations 

with the units at both sites. 

−  Two-level redundant safety systems, including in particular: 1st and (bunkered) 2nd level 
emergency diesel generators and power supply systems, seismically qualified for all units 
at  both  sites  (with  the  exception  of  the  1st  level  diesel  generators  (DGs)  in  Doel  1/2, 
which will be completed by mid-2012). 

−  Auxiliary feedwater turbo-pumps (in each unit). 

−  Emergency steam-driven turbo-alternator (Tihange 1). 

−  Primary and alternate ultimate heat sink (UHS) available at both sites. 

−  Diverse other water sources (including unconventional) and inter-connection possibilities 

available at the plant sites. 

−  Many  non-conventional  means  (NCMs  -  mobile/portable  equipment)  are  available, 
including mobile diesel-driven pumps and mobile diesel generators, and their connections 
are already implemented (for electrical power and water supply). 

−  Long autonomy of AC power sources and batteries. 

−  The integration of the non-conventional means into the accident management procedures 
and SAMG and benchmarking it with US NRC Extensive Damage Mitigation Guidelines. 

Safety improvements implemented or planned (non-exhaustive list): 

−  Performing more detailed seismic hazard studies. 

−  Enhancing  external  power  supply  reliability  in  the  Tihange  NPP  through  a  better 

separation of  the high-voltage  (380 and 150 kV) lines. 

− 

Increasing  the  capacity  of  auxiliary  feedwater  tank  and  adding  a  motor-driven  pump  in 
Tihange 1. 

−  Solving  the  problem  of  refilling  the  primary  circuit  during  mid-loop  operation  and  with 

primary system open in case of the total SBO in Tihange 3. 

−  Modifying the spray system in order to achieve an alternative spraying flow with a mobile 

spraying pump at Doel 3 & 4 units. 

−  Performing seismic qualification of the refuelling water storage tanks at Doel 1/2. 

−  Enhancing protection against external hazards (earthquake, flooding, weather conditions) 

of the following areas:  

• 

• 

• 

At  the  Doel  NPP,  the  construction  of  a  new  seismically  qualified  building 
which is also protected against flooding, is planned; this building will be used 
as  a  location  for  storage  of  NCM  (including  fire  trucks)  that  are  expected  to 
ensure the safety function in case of extreme external hazards. 

Performing seismic upgrade of the AFW-turbo pumps and their tanks at Doel 
1/2. 

Assessment of strengthening the electrical building of Tihange 1 unit 

17 

 
 
• 

• 

Improving volumetric protection of the Tihange site, and the reinforcement of 
the river embankment of the Doel site. 

Enhancement  anti-flood  protection  measures  at  Tihange,  in  particular  its 
emergency  power  supply  systems,  assuming  the  10 000  year  recurrence 
frequency type of flooding (to prevent the loss of safety functions). 

− 

Improving the following power supplies: 

• 

• 

• 

• 

Alternative  power  supply  (380V)  for  non-conventional  means  or  safety 
equipment  

Alternative  power  supply  (380V)  for  rectifiers;  this  measure  ensures  the 
possibility to recharge the batteries before their total depletion during an SBO 
event 

Introduction  of  a  procedure  for  minimizing  the  diesel  generators  fuel 
consumption  

Purchase  of  a  fuel  tanker  truck  for  the  on-site  transportation  of  diesel  fuel 
(Doel) 

−  Constructing a new demineralized water production circuit at the Tihange site. 

−  Ensure  procedures  take  into  account  events  such  as  loss  of  the  primary  UHS  affecting 
more  than  one  unit,  total  SBO,  and  load  shedding  to  increase  the  batteries  autonomy. 
Enhancing the organization and logistics of the internal emergency plan to include “multi-
unit” events. 

− 

Implementing continuous measurement of water level in SFPs in the Tihange NPP units 
where this is not in place yet.  

− 

Improving SAMG with decision support tools, long term monitoring and exit guidelines. 

−  Adapting strategies for flooding reactor pit before reactor vessel rupture. 

− 

Installing additional instrumentation (e.g. pH sump, bottom reactor vessel) and identifying 
effective means to control pH inside containment. 

−  Applying  specific  provisions  (maintenance,  inspections,  testing)  to  non-conventional 

means credited in analyses. 

5.2. 

BULGARIA 

Recommendations:  

−  Adequacy  of  paleoseismological  studies  should  be  further  analysed  throughout  the 
periodic  updates  of  the  seismic  PSA  and  in  the  PSR,  on  the  basis  of  the  information 
available and verified, to evaluate the need of re-assessment of the seismic hazard on site.  

− 

Implementation  of  the  complementary  improvement  measures  for  beyond  design  basis 
conditions  identified  in  the  Action  Plan  (such  as  improvement  of  the  leak  tightness  of 
certain rooms below ground level) should be monitored.   

−  A combination of extreme weather conditions still needs to be considered.  

18 

 
 
−  Although the batteries have 10 hours discharge time, a possibility of their recharging from 

a mobile DG should be considered.  

−  Concerning  SAM,  there  is  still  an  open  issue  under  which  conditions  is  the 
implementation  of  different  SAM  measures  feasible,  e.g.  due  to  possible  lacking  some 
hardware provisions for mitigation of severe accidents. It is recommended that additional 
improvements 
Implementation  of 
Recommendations  Following  the  Stress  Tests  Carried  out  on  Nuclear  Facilities  at 
Kozloduy NPP plc.” is pursued. 

for  SAM  covered  by 

the  “Program 

for 

Good practices:  

−  During the country visit it was noticed that periodic and frequent walk downs on SAMGs 

provisions are performed, this is considered as a good practice. 

Safety improvements implemented or planned (non-exhaustive list):  

Some examples of measures for improvement of plant robustness related to the two operating 
units 5 & 6 at Kozloduy NPP are, as follows: 

−  Studying the possibilities for alterative options for Units 5 and 6 decay heat removal using 

the existing SG emergency makeup system (EMS) of Units 3 and 4. 

−  Securing the availability of at least one tank of the SG Emergency Feedwater System in 
shutdown mode in order to provide for the use of the SG as an alternative for the residual 
heat removal. 

−  Two  new  mobile  DGs  will  be  delivered,  and  the  existing  one  will  be  maintained  in 
standby  conditions  for  the  remaining  structures  at  the  NPP  area;  Power  supply  from  a 
mobile DG is provided for charging the accumulator batteries of the safety systems. 

− 

Implementation  of  the  symptom  based  EOPs  for  the  shutdown  states  with  open  reactor, 
and implementation of SAMGs. 

−  Development of technical means for direct water supply to the steam generators, SFPs and 

the containment using mobile fire equipment. 

− 

− 

Installation of additional hydrogen recombiners in the containment. 

Installation of instrumentation for monitoring of steam and oxygen concentrations in the 
containment, and for monitoring the temperature in the reactor vessel 

−  Updating  on-site  and  off-site  emergency  plans,  taking  into  account  (a)  difficulties  in 
accessing the emergency control rooms of Units 5+6; possible drying out of the SFS basin 
compartments, with subsequent increase of dose rates; and (c) providing alternative routes 
for evacuation, transport of fuels and materials and access of staff. 

−  Construction of a new Emergency Management Centre, outside the Kozloduy site. 

5.3. 

CZECH REPUBLIC 

Recommendations:  

−  The  reviewers  recommend  the  regulator  to  consider  the  implementation  of  diverse 
ultimate heat sink at Dukovany NPP due to inadequate capability of the cooling towers in 
regard to hard wind and seismic hazard. 

19 

 
 
−  The  reviewers  recommend  the  regulator  to  consider  the  qualification  of  equipment  and 
systems needed to manage SA, especially system ensuring power supply like hydro power 
plant connection, diesel generators. 

−  The  reviewers  recommend  the  regulator  to  consider  modifications  on  emergency 
procedures,  staffing  of  emergency  response  organization  and  analysis's  regarding  the 
usability of the shelter under flooding conditions. 

−  The reviewers recommend the regulator to consider increasing the protection of diesel fuel 

pumps against flooding effect at Temelin NPP. 

−  The battery autonomy is currently an issue that needs to be addressed at all operating NPP 
designs. The reviewers recommend the regulator to consider the benefits of recharging the 
batteries before their complete depletion in case of total SBO in addition to ensuring the 
depletion time / battery capacity increase. 

−  The  reviewers  recommend  the  regulator  to  consider  studies  of  using  a  filtered  venting 
system to protect the containment against loss of integrity and to reduce significantly the 
releases  of  radioactivity  to  the  environment  in  case  of  severe  accidents,  as  the  current 
system is not designed for severe accident conditions.  

−  The  reviewers  recommend  the  regulator  to  consider  studies  on  hydrogen  management 
considering  reactor  and  SFP  building  and  the  installation  of  additional  re-combiners 
sufficient for severe accident conditions at Temelin and Dukovany NPPs. 

−  Mid-loop  operation  at  Temelin  NPP  is  a  critical  issue  in  case  of  SBO.  The  licensee 
announced  that  it  eliminates  the  mid-loop  mode  of  operation  from  the  regular  outage 
schedule. The reviewers recommend the regulator to follow up the announcement. 

−  The reviewers recommend the regulator to consider increasing of the plant robustness by 
implementation  of  alternative  means  for  AC  power  supply  for  core  cooling  and  heat 
removal. 

Good practices:  

−  The proposal by the regulator to establish common emergency response arrangements for 

several neighbouring countries. 

Safety improvements implemented or planned (non-exhaustive list):  

−  Finalization of safety upgrading to the currently approved design Basis Earthquake by the 

end of 2015 for Dukovany NPP. 

−  Upgrading of fire brigade building for seismic resistance.  

−  Discussions of further hardware implementation to cover severe accident (primary circuit 

depressurization, hydrogen management for severe accident, containment isolation). 

− 

− 

− 

Installation of connection points for water supply from fire brigade pumps. 

Improvement  and  finalization  of  EOPs  and  SAMGs  including  shutdown  states,  open 
reactor,  SFP  and  multi-unit  accidents.  Further  analysis  of  the  impact  of  damage  of  the 
infrastructure. 

In  particular,  the  following  measures  indicated  in  the  national  report  have  to  be 
implemented: 

• 

alternative containment sump water make up (Temelin) 

20 

 
 
• 

• 

• 

• 

• 

• 

selection  and 
containment from the overpressure loads 

implementation  of  appropriate  solution 

for  protecting 

providing  mobile  (portable)  equipment  for  ensuring  feasibility  of  the  SAM 
actions 

increase robustness of storage building structures for mobile devices including 
fire trucks, or relocation of equipment 

implementation of ex-vessel cooling at Dukovany NPP 

analysis of molten core cooling in Temelin NPP 

installation of additional re-combiners sufficient for severe accident conditions 
at Temelin and Dukovany NPPs. 

5.4. 

FINLAND 

Recommendations:  

−  Seismic justification of structures, systems and components (SSC) is based on the seismic 
PSA. The peer review recommends that STUK should consider additional assessment of 
critical SSC with respect of PGA = 0.1g (as recommended in the IAEA Safety Guide NS-
G-3.3). 

−  The peer review recommends that the assessment of the drainage system capacity in case 

of high seawater level should be considered.      

− 

It was noted that Olkiluoto 1 & 2 are vulnerable to SBO (short coping time), particularly if 
it  occurs  at  the  time  of  reactor  scram.  It  was  also  noted  that  a  heat  sink  completely 
independent  of  seawater  does  not  currently  exist  at  Olkiluoto  1  &  2.  The  peer  review 
recommends that corresponding planned corrective measures should be implemented. 

−  General  suggestion  is  to  perform  special  tests  of  several  equipment,  among  them  DC 
batteries up to depletion, endurance tests of diesel generators, under extreme conditions, 
training of some activities as for instance hoses installation etc. 

−  The reassessment of  the  emergency preparedness  should  address events  that occur at all 
the  units  on  site  at  same  time.  The  peer  review  recommends  that  the  scope  of 
EOPs/SAMG  should  also  include  all  shut  down  states  and  that  the  availability  of 
dedicated systems and components to be used during severe accidents scenarios should be 
verified. 

Good practices:  

The detailed and strict legal basis regarding the emergency preparedness and severe accidents 
management is a strong point. Already implemented provisions enhancing robustness can be 
considered  as  advantages  when  assessing  the  safety  of  Finish  NPPs  against  hazards  that 
contributed the Fukushima accident. Several good practices were identified as follows: 

−  At Loviisa 1&2, independent air cooled SAM diesel generators (not depending on EDGs), 
dedicated  SAM  valves  for  Reactor  Coolant  System  (RCS)  depressurization  measure 
providing external cooling of the vessel in case of a core meltdown accident, containment 

21 

 
 
external spray (dedicated SAM system), and operational by mobile equipment in case of 
loss of its own pumping capability. 

−  At Olkiluoto 1&2, means for flooding the lower drywell, depressurisation of the RCS and 
diversification  for  keeping  the  valves  open,  modifications  to  protect  the  drywell 
penetrations  against  pressure  and  thermal  loads),  filtered  venting  system  of  the 
containment (a dedicated SAM system), and possibility to fill the containment with fresh 
water. 

Safety improvements implemented or planned (non-exhaustive list):  

There is a long list of safety improvements that were either implemented or are planned. Here 
are some examples: 

−  Continues  decreasing  the  seismic  risk,  which  includes  replacement  of  plant  equipment 
with  new,  seismically  qualified  equipment,  (i.e.  relays  especially  for  eliminating  relay 
chatter, steel racks for batteries), and the study of seismic fragilities of pool structures in 
reactor containment and pools in spent fuel storages. 

−  At Loviisa, the licensee is studying modernization the bulkhead used to close the cooling 
water  discharge  openings,  etc.  A  water  tightness  and  water  pressure  tolerance  of  doors 
leading to the basement of the reactor building and consequences of the eventual leakages 
will be investigated and improved if needed.  

−  At Loviisa, evaluation of mobile devices to ensure boron injection into the RCS, coolant 
inventory in the secondary circuit, water supply for the diesel driven auxiliary emergency 
feed  water  pumps,  electricity  supply  for  instrumentation  needed  in  accidents,  electricity 
supply  for  the  RCS  depressurisation  valves,  containment  heat  removal  during  severe 
accidents,  decay  heat  removal  from  the  spent  fuel  storage  pools,  control  room  lighting, 
and plant communication systems. 

−  To increase robustness of the UHS, two cooling towers per unit are under consideration, 
one  removing  decay  heat  from  the  reactor  and  one  the  decay  heat  removal  from  the  in-
containment spent fuel pool and the spent fuel storage pools; 

−  At  Olkiluoto  1  &  2  possible  renewal  of  all  eight  emergency  diesel  generators;  the  new 
EDGs  would  have  two  diverse  component  cooling  systems,  allowing  for  air  cooling, 
improved water tightness of the rooms, and improved local control room. Installation of a 
so called 9th EDG that could supply electric power to either Olkiluoto 1 or 2. This EDG 
would be located in a new, separate diesel building, qualified for flooding. 

− 

Installation  of  diverse  and  independent  way  of  pumping  water  to  the  reactor  pressure 
vessel via fire fighting diesel driven pumps (Olkiluoto 1&2). 

−  STUK requested the licensee to provide a plan and schedule to secure decay heat removal 
from reactor core and containment in case of total loss of AC power (Olkiluoto 1&2); 

−  At Loviisa NPP, licensee has performed the following measures to enhance the accident 

management capabilities: 

• 

• 

number of staff in the technical support emergency organization was recently 
increased for better preparedness and support against accident situations; 

improvements  to  guidance  for  accident  management  (SAM  Guidelines  and 
SAM  handbook)  concerning  spent  fuel  pools  and  storages    are  under 
development; 

22 

 
 
• 

reduction of bypass sequences frequencies will continue in the future. 

5.5. 

FRANCE 

Recommendations:  

for  seismic  hazard  assessment. 

−  The DBE has been developed according to the French regulation, based on a deterministic 
recommends  conducting  both 
approach 
is 
deterministic  and  probabilistic  approaches,  as  complementary  strategies. 
recommended that ASN consider introducing PSHA in France for the design basis of new 
reactors and for future revisions of the seismic design basis of existing reactors, in order to 
provide  information  on  event  probability  (annual  frequency  of  occurrence)  and  to 
establish a more robust basis for DBE specifications. 

IAEA 

It 

−  The seismic margins for seismic events above the DBE have been roughly estimated by 
the  licensee.  The  reviewers  recommend  the  regulator  that  a  more  systematic  evaluation 
will be used either by performing PSA or SMA as well as introducing PSHA in France. 

−  The  reviewers  recommend  the  regulator  to  improve  the  seismic  instrumentation  at  the 

plants. 

−  ASN explained that the design basis flood is defined considering statistical extrapolations 
limited  to  10-3/y  supplemented  by  a  margin  or  a  conventional  combination.  ASN  and 
IRSN  stated  that  the  current  state  of  the  art  in  flood  level  calculations  doesn't  allow 
calculating, with a sufficient confidence, 10-4/y levels, except in some specific conditions 
such as "small catchments areas - up to some 1000 km2". It is recommended to perform a 
comparative evaluation with the methodologies used in other European countries. 

−  The regulator asked the licensee to conduct the analyses of climatic phenomena related to 
flooding.  The  reviewers  recommend  the  regulator  to  consider  including  also  tornadoes, 
heavy  rainfall,  extreme  temperatures  and  the  relevant  combinations  of  extreme  weather 
conditions in these complementary studies.  

−  The battery autonomy is currently an issue that needs to be addressed at all operating NPP 
designs. The reviewers recommend the regulator to consider the benefits of recharging the 
batteries before their complete depletion in case of total SBO in addition to the foreseen 
battery capacity increase. 

−  The  main  improvements  to  be  made  in  order  to  cope  with  severe  accidents,  possibly 
affecting multiple units and caused by natural hazards have been pointed out by ASN. One 
basic  recommendation  of  the  peer  review  process  is  to  guarantee  their  actual 
implementation. The reviewers consider the identified actions to be adequate for a further 
improvement of safety features. The consideration and implementation of these issues is 
important to be realized as soon as possible, apart from the PSRs, which are usually the 
reference for introducing new safety standards in France.  

Good practices:  

−  Continuously  safety  upgrading  of  the  plants  by  regularly  implementation  of  new  safety 

features in the framework of the period safety reviews  

−  The licensee announced the creation of specialized crews and equipment in order to cope 
with accidents in 24 hours. These crews will be made up of the licensee's employees at all 
plant sites and equipment will be stored in 4 regional centres.  

23 

 
 
Safety improvements implemented or planned (non-exhaustive list):  

−  The regulator requires the licensee to define a certain "Hardened safety core" of material 
and  organizational  measures.  The  hardened  safety  core  will  be  based  mainly  on  new 
equipment  diversified  form  the  existing  one  to  prevent  common  cause  failure.  This 
hardened safety core should include: 

• 

• 

• 

• 

• 

• 

• 

• 

the  emergency  management  rooms  and  equipment  (they  must  display  high 
resistance to hazards and allow the management of a long-duration emergency) 

the mobile devices vital for emergency management; 

the  active  dosimetry  equipment,  the  measuring  instruments  for  radiation 
protection and the personal and collective protection equipment, which must be 
permanently available in sufficient quantity on the sites 

the technical and environmental instrumentation for diagnosing the state of the 
facility and assessing and predicting the radiological impact on the workers and 
populations 

the communication means vital for emergency management 

strengthened equipment including, for operating NPPs:  

−  mobile electricity generating set 

−  diesel-driven  emergency  cool  down  water  supply  for  each  reactor 

primary and secondary circuits. 

−  ultimate backup diesel generator (DUS) for electrical backup of control 

room ventilation and instrumentation useful and necessary in SA 

qualification  against  external  hazards  of  the  hydrogen  re-combiners  and  the 
venting filters system 

improvement and updating of SAMGs including all operation states, SFP and 
multi/unit events 

−  The  licensee  proposes  several  improvements  or  studies  to  reinforce  the  management  of 
accident or severe accident situations on its sites including the provisions for multiple unit 
events. These improvements target more particularly: 

• 

• 

• 

• 

appropriateness  of  the  human  and  material  resources  for  the  activities 
associated  with  deployment  of  the  "hardened  safety  core"  equipment  and  the 
additional equipment proposed; 

reinforcement of the material resources and communication means; 

conducting  a  study  to  improve  the  resistance  and  habitability  of  the  safety 
building; 

integrating  stringent  habitability 
design  of  Local  Emergency  Centres, 
requirements and allowing more effective management of the emergency. The 

24 

 
 
design  requirements  taken  into  account  shall  be  consistent  with  those  of  the 
hardened safety core; 

• 

• 

reinforcement  of 
technical  and 
environmental information transmission, including meteorological information, 
necessary for emergency management; 

the  means  of  measurement  and  of 

complementary  measures  to  reduce  the  risk  of  loss  of  water  inventory  in  the 
SFPs. 

5.6. 

GERMANY 

Note: German stress tests cover also several man-induced events, such as aircraft crash, blast 
wave, toxic gases, terrorist and cyber-attacks.  

In  the  safety  review  by  the  German  Reactor  Safety  Commission  (RSK),  the  assessment 
criteria  for  a  postulated  aircraft  crash  differ  in  three  Degrees  of  Protection.  A  difference  is 
made  between  the  mechanical  impact  (impact  of  the  aircraft)  and  the  thermal  impact 
(kerosene fire). The Degree of Protection is considered according to the crash of an aircraft 
comparable to a Starfighter (Degree of Protection 1), the crash of a medium-size commercial 
aircraft  (Degree  of  Protection  2)  and  additionally  of  a  large  commercial  aircraft  (Degree  of 
Protection 3). 

Recommendations: 

−  For German NPP sites the PGA values are in some cases lower than 0.1g. As it deviates 
from the approach recommended by the IAEA, and it is recommended that the regulator 
should consider a minimum value of 0.1 g. 

− 

It is recommended to install seismic instrumentation at some NPPs in northern Germany 
where it is currently not required. 

Good practices: 

−  SAM measures including significant hardware modifications are in place for many years 
(for  PWRs:  Secondary  side  Bleed  &  Feed  including  mobile  pumps  to  feed  the  SG;  for 
BWRs:  diverse  RPV  depressurization  and  injection  systems,  mobile  pumps  for  RPV 
injection; for both: PARs, Filtered Venting Systems…). 

−  Nuclear intervention force exists since 1977. 

−  Main control room habitability during filtered venting is ensured. 

−  Emergency  response  organization  could  be  housed  in  different  buildings.  Alternative 

support centre is part of concept. 

Safety improvements implemented or planned (non-exhaustive list):  

−  Only  4  of  the  NPPs  have  performed  a  seismic  PSA.  The  next  round  of  PSRs  might  be 
used to review the seismic hazard and design for all plants, which remain in operation. 

−  At Gundremmingen plant, feasibility studies to increase the AC power supply robustness. 

25 

 
 
−  Unterweser  NPP  applied  for  license  for  measures  aimed  at  using  a  fire  water  pump  to 
sustain  low-pressure  feed  to  the  emergency  feed  water  system  or  to  the  emergency 
condition diesel system even under harsh ambient conditions. 

−  At Isar-1 plant plans for installing two new emergency diesel generator buildings and for 
replacing the water-cooled emergency diesel generator with new air-cooled, diverse units. 

−  The  GRS  information  notice  WLN  2012/02  contains  22  recommendations.  It  includes, 
e.g.,  the  following  topics:  SBO  coverage  for  at  least  10  hours,  additional  emergency 
power generator available within 10 hours, diverse ultimate heat sink, two feeding points 
for connection of mobile equipment to supply the essential component cooling system. 

−  Systematic  inclusion  of  internal/external  hazards  into  the  AM  Program  (including 

operability of mobile equipment). 

−  Development of AM measures to protect the building structure surrounding the spent fuel 
pool  in  a  BWR,  which  is  outside  the  containment,  against  hydrogen  combustions  or  to 
prevent them. 

−  SAMGs for full power states exist for one NPP (GKN-1) and are being developed for all 
operating NPPs. No low power or shutdown SAMGs exist (but there is some guidance in 
operational manuals). 

5.7. 

HUNGARY 

Recommendations: 

−  Regarding earthquake, it is recommended to the Regulator to monitor implementation of 
the  measures  for  further  strengthening  the  level  of  protection  of  plant  structures  against 
liquefaction  effects  and  soil  settlement,  as  well  as  for  the  completion  of  seismic 
qualification  of  certain  SSCs  and  a  review  of  the  database containing  the  seismic  safety 
classification of components. 

−  Concerning  flooding,  it  is  suggested  to  the  Regulator  to  monitor  implementation  of 
specific  measures  for  strengthening  the  level  of  protection  of  the  essential  service  water 
system. 

− 

It  is  suggested  to  the  Regulator  to  monitor  implementation  of  specific  measures  for 
strengthening  the  level  of  protection  of  plant  SSCs  against  extreme  weather  conditions. 
Special attention should be paid to assessing vulnerability of the rain drainage system in 
case of BDB of extreme precipitation and snowmelt. 

−  Concerning  loss  of  safety  functions,  the  possibilities  of  interconnection  of  existing 
equipment  are  beneficial.  However  this  might  also  lead  to  loss  of  separation.  Such 
improvements  or  modifications  should  only  be  carried  out  after  careful  investigation  of 
separation issues. 

− 

In the area of SAM, to reduce radioactive release to the environment in case of long term 
severe accident and to avoid over-pressurization a filtered containment venting system or 
a  specific  containment  cooling  system  should  be  installed  at  all  units,  as  the  actual 
measures for long term internal containment cooling are considered to be adequate only in 
the case of a successful in vessel retention of the molten core. 

−  Water  supply  to  the  SFP  from  an  external  source  has  to  be  made  possible  by  pipeline 
having adequate design against external hazards, with additional connection from outside. 

26 

 
 
Water  with  boron  concentration  has  to  be  supplied  through  this  line  to  the  SFP.  The 
operating instructions have to be developed. 

−  Liquid  radioactive  waste  management  procedures  have  to  be  developed  for  severe 

accident situations 

−  The  management  of  on-site  consequences,  especially  of  multi-unit  accidents,  has  to  be 

improved. 

Good practices:  

−  Regarding earthquake, the reviewers acknowledge the measures undertaken to upgrade the 
plant, which was originally not designed to withstand earthquakes, to its current standard.  

−  Concerning flooding, a strong safety feature of the plant is its site ground elevation above 
maximum  possible  water  level  in  case  of  flooding  caused  by  high  flow  pattern  of  the 
Danube River or dam break. 

−  The requirement of SAMG in the national regulatory framework and the decision of the 
regulatory authority to require implementation of SAM measures as pre-conditions for the 
life extension for all units are commendable. 

−  EOPs  and  SAMGs  have  been  developed  for  all  operating  modes  (normal  operating  and 

shutdown), for SFP accidents in all units. 

−  The  arrangements  in  place  in  the  Protected  Command  Center  (PCC)  regarding  power 
supply, worker protection against external hazards (dose, contamination, etc.), display of 
plant critical parameters during a severe accident are commendable. 

Safety improvements implemented or planned (non exhaustive list):  

−  The  programme  on  development  and  implementation  of  hardware  measures  for  severe 
accident mitigation measures and of SAMGs was started before the Fukushima accident 
and  is  still  on-going.  As  part  of  this  programme,  the  installation  process  of  hydrogen 
recombiners was accelerated after Fukushima accident and is now completed in all units. 

−  Several measures have been envisaged to increase the robustness of the plants in case of 

loss of electrical power, among others: 

• 

• 

• 

The protection of 400 kV and 120 kV substations and of the automatic switch 
to  island  mode  will  be  evaluated  against  earthquakes,  and  improved  as 
appropriate. 

In addition to the existing severe accident diesel generators supplying electrical 
power to I&C systems described in accident management procedures, diverse 
diesel generator, which can supply electrical power to safety consumers having 
role in severe accident prevention and long term accident management is being 
considered.  

The  black  start  ability  of  the  gas  turbine  located  in  Litér  will  be  assured  by 
installing a diesel generator. 

−  To enhance the resistance of the plant in the case of loss of UHS several modifications are 

planned such as maximizing the inventory of the stored demineralised water. 

−  Finally, further studies on SAM are planned in the following topics: 

27 

 
 
• 

• 

• 

• 

Hydrogen generation and distribution in the reactor hall 

Long-progression with containment pressurization during severe accidents 

Updating the Level 2 PSA studies 

Development of a software based severe accident simulator. 

5.8. 

LITHUANIA  

Recommendations:  

−  To  perform  a  BDBE  analysis  for  the  new  spent  fuel  interim  storage  by  postulating 
cracks/collapse  of  walls  of  cask  storage  hall  and  hot  cell,  cracks  or  collapse  of  the 
guarding  concrete  fence,  turnover  of  casks  during  transportation,  loss  of  cask  sealing  as 
well as cask blockage by debris.  

−  To perform a BDBE analysis of the accident management centre structure to confirm their 

seismic capability. 

−  To  examine  the  possibility  to  use  signals  of  seismic  alarm  and  monitoring  systems  to 
formulate emergency preparedness criteria (and include them in the relevant procedures or 
guidelines). 

−  To  consider  the  need  for  a  further  PSR  for  reactor  unit  2  and  the  SFPs  if  the 

decommissioning phase is delayed. 

−  To  consider  the  benefits  of  qualifying  the  level  and  temperature  instrumentation  in  the 
SFPs for accident conditions and having these signals available in all relevant locations. 

Good practices:  

−  A strong feature is the 2 hydro plants that can provide electrical power when the off-site 

power is lost.  

−  Accessibility of the SFPs under SA conditions has been considered and Ignalina NPP has 

radiation protection provisions in case manual actions are required. 

Safety improvements implemented or planned (non-exhaustive list):  

−  Development of BDBA guidelines. 

−  To  install  mobile  DG  connections  to  important  to  safety  I&C,  radiation  monitoring 
system,  communication  system,  recharging  point  for  the  batteries  of  flashlights,  and 
temperature  and  level  indicators  of  the  SFP  (and  to  install  DG  connections  to  these  last 
indicators), and to other consumers. 

−  To use domestic potable water pumping system with own backup DG as diverse heat sink 

cooling for the reactor and SFPs. 

−  Modifications to supply Unit 1 systems by Unit 2 DGs. 

28 

 
 
5.9. 

THE NETHERLANDS 

Note: The assessment by the Netherlands included also airplane crashes in its scope, and the 
national regulator confirmed that a more extensive study of the impact on the safety functions 
of different airplane crashes has to be performed as proposed by licensee EPZ. 

Recommendations:  

−  The seismic hazard assessment should be updated for Borssele NPP. It is understood that a 
comprehensive and state-of-the-art seismic analysis will be performed as part of the PSR 
of the Borssele NPP starting in 2012. 

−  This  analysis  will  then  consider  a  PGA  value  of  0.1g  at  free  field  for  the  DBE,  as  per 
IAEA  guidance.  The  reviewers  recommend  to  follow-up  the  mentioned  analysis  for 
verifying its global scope and adequate performance, in particular concerning the revision 
of the DBE level. 

−  The  combination  of  young  unconsolidated  sediments;  grain  size  effects;  and  high  water 
tables  are  expected  to  make  the  site  susceptible  for  liquefaction.  It  is  therefore 
recommended  that  the  national  regulator  should  consider  assessing  the  liquefaction 
problem in connection with the on-going seismic analyses. 

−  Considering the very specific approach of the Netherlands for the flooding protection of 
the site, which relies on the national dyke system, the reviewers recommend to examine 
thoroughly the consistency of this approach with the new IAEA guidance (SSG-18). 

−  Further  recommended  topics  that  should  be  considered  for  additional  studies  are: 
minimum  depth  of  underground  piping  required  for  proper  protection  against  freezing, 
possibility  to  operate  diesel  generators  at  extremely  low  temperatures  and  the  potential 
effect of accumulation of wind transported snow on roofs. 

−  The  capabilities  to  cope  with  SBO  situations  during  mid-loop  operation  should  be 
developed  and  corresponding  procedures  should  be  prepared  and  validated.  Due  to  the 
short  times  available  for  manual  intervention  and  the  worsening  accessibility  of  the 
containment after the start of water boiling in the open primary circuit, the possibility to 
use  remotely  controlled  valves  allowing  for  primary  system  water  make-up  in  case  of 
SBO during mid-loop operation should also be investigated. 

−  Possibilities  to  increase  the  robustness  of  back-up  power  supply  from  mobile  means,  as 
well as from small portable equipment, should be further investigated considering external 
support. 

−  The  Dutch  regulator’s  suggestion  for  further  analysis  to  establish  the  validity  of  the 
assumptions  made  regarding  the  SSCs  needed  for  SAM  is  supported  and  should  be 
pursued as a matter of priority. 

−  The  maintenance  schedule  for  equipment  related  to  accident  management  should  be 

reviewed by licensee. 

−  Unambiguous  tagging  of  keys  of  rooms  (e.g.  emergency  control  room)  in  the  bunkered 

building should be implemented. 

−  The licensee should consider placing the SAM execution procedures at the location where 

they are to be used. 

Good practices:  

29 

 
 
 
−  Use of risk monitor for planning maintenance during operation and outages. 

−  Explicit  incorporation  of  international  standards  (e.g.  those  of  IAEA,  WENRA)  into  the 

license via the Nuclear Safety Rules (NVRs) approach. 

−  Borssele  has  SAMGs  for  all  operational  states  (including  shutdown).  The  licensee  has 
been  very  proactive  in  this  regard,  implementing  them  far  faster  than  in  many  nations 
reviewed. Its SAMGs were considered state of the art in 2003. 

−  Borssele has used a full scope Level 3 PSA for deriving its severe accident management 

strategies and has been subject to IAEA IPSART missions. 

−  The scale of emergency exercises at Borssele is unusually large by international standards 

– one recent national exercise involved 1000 people. 

−  PARs are already installed and are designed for severe accident conditions. 

Safety improvements implemented or planned (non-exhaustive list):  

−  Storage  facilities  for  portable  equipment,  tools  and  materials  that  are  accessible  after  all 
foreseeable hazards would enlarge the possibilities of the alarm response organization. 

−  Ensuring  the  availability  of  fire  annunciation  and  fixed  fire  suppression  systems  in  vital 
areas  after  seismic  events  would  improve  fire  fighting  capabilities  and  accident 
management measures that require transport of water for cooling/suppression. 

−  Ensuring  the  availability  of  the  containment  venting  system  after  seismic  events  would 

increase the margin in case of seismic events. 

−  During  the  next  PSR,  either  a  seismic  PSA  will  be  developed  and/or  a  SMA  will  be 
conducted and the measures will be investigated to further increase the safety margins in 
case of earthquake. 

−  Modification in process to install a seismic monitoring instrumentation in the plant. 

− 

Improving flood resistance of buildings containing emergency supply. 

−  Regulator considers the impact of floods with long return period must be further assessed. 
Additional  study  on  extreme  flooding  with  long  term  period  including  dyke  failure 
mechanisms is envisaged. 

−  Development of an operating procedure for flooding has been initiated. 

−  The sea dyke A of 9,4 m + NAP will be improved in 2012. 

−  Develop  check-lists  for  plant  walk-downs  and  needed  actions  after  various  levels  of  the 

foreseeable hazards. 

− 

Improvement  of  plant  autonomy  during  and  after  an  external  flooding,  for  example  by 
establishing  the  ability  to  transfer  diesel  fuel  from  storage  tanks  of  inactive  diesels 
towards  active  diesel  generators  would  increase  the  margin  in  case  of  LOOP.  Envisage 
potential  actions  to  prevent  running  out  of  on-site  diesel  supply  for  fire  extinguishing 
system and the fire brigade. Increase the amount of lubrication oil in stock. By increasing 
the  autarky-time  beyond  10  h  the  robustness  of  the  plant  in  a  general  sense  would  be 
increased. 

−  Reducing connection time of the mobile Emergency Diesel Generator(s). 

30 

 
 
−  Better  arrangements  for  emergency  diesel  generators,  including  improved  means  for 

recharging batteries and strategies to conserve battery power. 

−  An  Emergency  Response  Centre  facility  that  could  give  shelter  to  the  alarm  response 
organization after flooding (and all foreseeable hazards) would increase the options of the 
alarm  response  organisation.  Establishing  independent  voice  and  data  communication 
under  adverse  conditions,  both  onsite  and  off-site,  would  strengthen  the  emergency 
response organisation. 

−  Assessment of the cooling possibilities in case of loss of the main Grid, Emergency Grids 

1 and 2 and no secondary bleed and feed available. 

−  Updated  and  extended  analysis  of  hydrogen  management  within  containment,  including 

for the SFP. 

−  Potential  improvements  to  SFP  cooling  arrangements  so  that  this  does  not  require  a 

containment entry. 

−  Strategies for corium stabilisation within containment. 

−  Revisiting previous analyses of ex-vessel Reactor Pressure Vessel cooling. 

−  Analysing the possibility of detonation / deflagrations in the containment filtered venting 

stack. 

−  Analysis  of  potential  doses  to  workers  during  severe  accident  management  activities, 
including  assessments  of  how  dose  levels  increase  with  reducing  Spent  Fuel  Pool  level 
and habitability of the Main Control Room and ECR. 

5.10.  ROMANIA 

Recommendations:  

−  The absence of a seismic level comparable to the SL-1 of IAEA leading to plant shutdown 
and inspection is regarded a critical issue at the background that the probability of large 
earthquakes  occurring  during  the  lifetime  of  the  plant  is  extremely  high  (recurrence 
intervals for the Vrancea seismic zone: 50y for Mw>7.4). It is suggested to the regulator 
to consider implementing adequate regulations. 

−  There is only little information about margins to cliff edges, weak points and no evidences 
that further improvements in the seismic upgrading have been considered. Further work is 
proposed  in  this  area  and  it  is  recommended  that  the  CNCAN  obtains  good  quality 
programmes from the licensees and ensures that the work is appropriately followed up. 

− 

It is suggested to consider improving the volumetric protection of the buildings containing 
safety related equipment located in rooms below plant platform level. It is also suggested 
to the regulator to consider routine inspections of the flood protection design features. 

−  The habitability of the MCR and SCA was assessed for various types of accidents but not 
in the case of a total core melt accident associated to a containment failure (or voluntary 
venting).  MCR  habitability  analysis  to  be  continued  (e.g.  implementation  of  a  close 
ventilation circuit with oxygen supply). 

−  Further SAM study is required for shutdown states.  

Good practices:  

31 

 
 
 
−  The  plant  units  have  a  high  level  of  defence  against  the  loss  of  power  and  its 
consequences. The robustness of the electrical power supply is provided by four levels of 
defence in depth. 

−  The dousing tank of the CANDU design allows gravity feed into the Steam Generators. 

−  The primary and alternative heat sinks provide a good level of redundancy and diversity. 

−  Possibility  to  use  diverse  methods  to  open  the  Main  Steam  Safety  Valves  if  the  normal 

power supplies are lost. 

−  The robustness of the CANDU design to SA progression (slow accident progression due 
to  the  quantity  of  water  available  in  the  vessel  and  calandria  vault,  which  increases  the 
chances  to  stabilize  a  degraded  situation  and  limit  the  possibility  of  large  early  release 
(except for hydrogen combustion), 

−  The large spreading area in case of MCCI which contributes to the possibility of corium 

cooling in the late phase of an accident. 

Safety improvements implemented or planned (non-exhaustive list): 

−  Two  new  mobile  diesel  generators  for  electrical  power  supply  and  two  pumps  that  can 
provide  water  in  the  domestic  water  system  from  the  deep  wells.  In  order  to  further 
decrease  the  time  to  connect  the  mobile  DGs,  the  plant  has  initiated  a  modification  to 
install special connection panels to the loads which may be supplied from these DGs.   

−  Design  modification  for  water  make-up  to  the  calandria  vessel  and  the  calandria  vault 

(completed for unit 2). 

− 

− 

Improving  the  seismic  robustness  of  the  existing  Class  I  and  II  batteries.  The  option  of 
charging the batteries or the installation of a supplementary uninterruptible power supply 
for the SCA is being considered. 

Implementation of a hydrogen monitoring system (proposed by the utility and considered 
by  the  Romania  safety  authority  to  be  reliable).  PARs  on  unit  1  and  2  for  hydrogen 
management. 

−  Additional instrumentation for SAM (e.g. hydrogen concentration monitoring in different 

areas of the reactor building). 

−  Dedicated  emergency  containment  Filtered  Venting  System  (FVS)  for  each  unit  will  be 

installed. 

− 

Improving the reliability of existing instrumentation by qualification to SA conditions and 
extension of the measurement domain (e.g. 30 days resistance for cables and connectors). 

−  Spent Fuel pool: Use of a new, seismically qualified, fire water pipe to allow water make-
up without entering in the SFP area. Connections are provided outside the SFP building, 

−  Reinforced water height level instrumentation in the SFP and the reception bay. 

−  Cernavoda  NPP  will  establish  a  new  seismically  qualified  building  to  host  the  on-site 

Emergency Control Centre fire fighter’s facility and main intervention equipment. 

−  Cernavoda  NPP  will  increase  the  reliability  of  the  communication  systems  and  the 
robustness of the on-site emergency control centre. The set-up of an Alternative Off-site 
Emergency Control Centre is in progress.  

32 

 
 
5.11. 

SLOVAKIA 

Recommendations:  

− 

− 

− 

It  is  recommended  to  consider  monitoring  the  implementation  of  measures  for 
quantification  of  seismic  margins,  and  measures  for  strengthening  of  the  level  of 
protection of the plants against flooding and extreme weather conditions.  

In  order  to  assure  a  timely  completion  of  the  measures  for  seismic  resistance  of  the 
relevant  SSCs  of  Mochovce  NPP  1&2  for  the  newly  defined  Review  Level  Earthquake 
(PGA  of  0.15g),  it  is  recommended  to  consider  prioritization  of  the  seismic  upgrading 
measures,  e.g.  in  respect  to  the  fire  brigade  building,  and  to  re-evaluate  cases  where 
components of no primary safety feature potentially may have indirect influence on safety 
functions. 

It is important that the SAM modification will be implemented according to the proposed 
schedule. It is suggested to consider locating the special equipment for SAM in dedicated 
locations  qualified  against  external  hazards.  The  verification  of  tightness  of  all 
containment penetrations in SA conditions should be further examined (resistance of seals 
in particular). 

−  The strategy of long term management of containment pressure without any containment 
venting system should lead to further verification to check the real feasibility of long term 
containment heat removal in severe accident conditions. 

Good practices:  

−  The robustness of the plants against earthquakes has been significantly increased. 

−  Measures to improve the safety of the plants regarding LOOP, SBO and loss of UHS have 
been  planned  and  prioritised.  Good  practices  include:  large  capacity  of  batteries  and 
availability  of  several  batteries  trays;  battery  status  monitoring  system;  equipment 
configuration  management  system  dedicated  for  assessment  of  situation  during  extreme 
events  and  combinations  of  events;  availability  of  EOP  for  usage  of  water  from  bubble 
condenser tower for SFP cooling, filling up reactor vessel, cavity and pit; availability of 
EOP to remove the decay heat by steam generator when reactor is opened. 

−  Specific tests were performed to validate emergency measures (e.g. test of feeding steam 
generators  using  the  fire  truck  high  pressure  pump,  test  of  water  supply  to  SFP  from 
bubble condenser trays). 

−  Most  of  SAM  measures  are  not  yet  implemented,  but  regarding  the  future  situation  the 
following points can be highlighted as good practices: the SAM measures to avoid large 
early  releases  and  with  long  term  management  of  the  damaged  plant;  the  application  of 
EUR  safety  objectives  for  the  new  units;  the  continuous  improvement  of  containment 
tightness  of  all  plants;  the  new  concept  for  the  emergency  control  centres  with  remote 
control of SA equipment. 

Safety improvements implemented or planned (non-exhaustive list):  

−  Some additional safety upgrading measures are envisaged to increase seismic resistance. 

−  Some protective measures against flooding were promptly implemented during the period 
of stress tests (e.g. temporary passive protection of the reactor building and DG station). 
An  action  plan  for  implementation  of  short  term  and  long  term  corrective  measures  to 

33 

 
 
increase plant robustness against flooding with defined deadlines for implementation has 
been developed and agreed by the regulator. 

−  Further  work  is  defined  to  better  document  the  resistance  to  beyond  design  weather 

conditions. 

−  The  measures  to  increase  robustness  against  LOOP,  SBO  and  loss  of  UHS  include  the 
following: a 6kV air cooled diesel generator for SAM; a 0.4 kV mobile diesel generator 
for  each  unit  for  charging  batteries  and  supplying  selected  consumers  during  SBO; 
modifications of the power supply of the high-pressure boron system pumps enabling their 
use  during  SBO;  provision  of  a  mobile  high-pressure  feedwater  pump  for  each  unit  for 
injection into steam generators (available during SBO). 

−  An  extensive  project  for  the  implementation  of  the  plant  modifications  and  the 
development  of  the  SAM  was  confirmed  for  2013  for  Bohunice  (including  new 
improvements) and was accelerated from  2018  to  2015  for  Mochovce  NPPs.  It  includes 
reactor  cavity  flooding,  an  additional  line  for  RCS  depressurization,  containment 
hydrogen management, and containment vacuum breaker. 

5.12. 

SLOVENIA 

Note: The Krško NPP has also prepared an analysis of the impacts of aircraft crashes on the 
plant.  While  this  report  is  confidential  and  was  not  part  of  the  peer  review  process,  the 
national regulator states that the plant is well prepared even for such events. 

Recommendations:  

−  The new updated seismic hazard assessment resulted in a decrease in seismic margins. It 
is  recommended  that  the  regulator  consider  requesting  the  update  of  the  seismic  design 
basis for future design modifications and consequently the associated PSA model.  

−  Additional systems and equipment that can ensure the main safety functions during LOOP 
and loss of UHS are planned to be deployed. It is recommended to complete these changes 
in a timely manner. 

−  Several provisions are already in place to support SAM with the use of mobile equipment, 
and  additional  upgrading  measures  (e.g.,  installation  of  PARs,  filtered  venting,  new 
emergency control room, third engineered safety features train) are being implemented. It 
is recommended to complete these improvements as soon as possible. 

Good practices: 

−  During the winter, warm water can be diverted from the essential service water to the inlet 

of the intake structure for de-icing purposes.  

−  At  extremely  low  temperatures,  daily  plant  surveillance  is  performed  for  all  open  air 
isolated  lines.  The  plant  has  in  place  several  heaters  which  can  be  used  to  heat  safety 
related SSCs even during a SBO. 

−  Sufficient mobile and portable power generation sources are available on-site. 

−  Turbine-driven  auxiliary  feedwater  pump  is  available  for  reactor  cooling  (provided  the 

SGs are available). 

−  Possibility of independent water injection into the reactor vessel. 

34 

 
 
−  SAMGs are validated by exercises on the full scope simulator and have been reviewed by 

IAEA RAMP mission in 2001.  

−  Full scope simulator used during drills provides real time response. Simulation goes up to 

containment failure and beyond. Longest exercise lasted 2.5 days. 

−  SAMGs are in place for the reactor as well as for SFP and are independent of the reactor 

operating state. 

−  Consideration of extensive damage due to aircraft crash and implementation of mitigation 

measures. 

Safety improvements implemented or planned (non-exhaustive list):  

−  Several  alternative  cooling  means  are  available  or  planned,  in  case  of  loss  of  primary 

UHS. 

−  Alternative means to provide suction to Auxiliary Feedwater System (AFW) pumps or to 

provide water to Steam Generators (SGs) directly. 

−  Alternative means for power supply to Chemical and Volume Control System in order to 
preserve reactor coolant system inventory and the integrity of reactor coolant pumps seals 
in  induced  SBO  or  Loss  of  essential  service  water  system  /  component  cooling  system 
conditions. 

−  Alternative means for power supply to selected Motor Operated Valves. 

−  Alternative means for providing water from the external sources to the containment. 

−  Procedures  for  local  operation  of  AFW  turbine  driven  pump  and  for  local  steam 

generators power depressurization without need of DC or instrument power. 

−  Third independent diesel generator 6.3 kV (in a separate building with the third safety bus 

which could be connected to either one of the existing two safety buses). 

−  Provision to connect mobile diesel generator of capacity 2000 kVA to switch gear of the 

third diesel generator. 

−  Two engine driven 125 V aggregates will be available to provide the power to DC system 

panels in case of loss of DC main distribution panels. 

−  Acquiring  onsite  additional  pumping  station  to  assure  additional  high  capacity  “portable 

water ring” around the plant. 

−  Acquiring  two  additional  high  pressure  mobile  fire  protection  pumps  (to  remove  decay 

heat in early stage after reactor shutdown and depressurizing SGs). 

− 

Installation of additional quick connection points for mobile equipment. 

−  Alternative means for makeup of Spent Fuel Pool water inventory. 

−  An alternative system with skid mounted pump and heat exchanger to cool the SFP. 

− 

Installation  of  a  special  emergency  control  room  in  the  already  constructed  building 
protected against external events. 

−  Filtered containment venting. 

−  PAR for hydrogen control in the containment. 

35 

 
 
−  A new Technical Support Centre with enhanced habitability requirements. 

− 

Improving existing flood protection by increasing the heights of dikes upstream the plant, 
in order to keep the left Sava river bank dry even for flows beyond the PMF flood flow.  

5.13. 

SPAIN 

Recommendations: 

−  Within the framework of the on-going analyses on the effects of pipe rupture (non-seismic 
and seismic), it is suggested to consider in particular verifying that there are no common 
cause failure issues. 

−  Within the framework the seismic hazard update, it is suggested that the updated Seismic 
Hazard  Assessment  should  use  the  available  geological  and  paleoseismological  data 
characterizing the active faults of the Iberian Peninsula. 

−  Adopting  a  consistent  approach  for  the  return  periods  associated  to  heavy  rain  and 

extreme temperatures scenarios at the different sites. 

− 

Improving the external flood volumetric protection of buildings containing safety related 
SSCs. 

−  Completing  the  establishment  of  a  comprehensive  set  of  requirements  for  accident 

management integrated within the Spanish legal framework. 

− 

It is suggested to consider containment filtered venting system in the NPPs. 

−  To  explicitly  include  accident  management  as  a  topic  in  CSN’s  safety  guide  on  "the 
content of periodic safety reviews” and to include External events in the scope of PSA. 

−  Reviewing  the  approach  linked  in  calculating  the  time  margins  for  the  control  or 

mitigation of severe accidents. 

−  Trillo:  development  of  symptom-based  SAMG  for  mitigation  of  the  consequences  of 

severe accidents and maintenance of containment integrity. 

−  Considering  passive  autocatalytic  hydrogen 

(NPP  Cofrentes  and 
Westinghouse NPPs) and a clear commitment for SAMGs for hydrogen mitigation in SFP 
accidents. 

re-combiners 

−  Developing severe accident management guidance for accidents initiated during shutdown 
operation and accelerating plans to include SAMGs addressing mitigating aspects for SFP. 

Good practices: 

−  A comprehensive analysis of indirect effects induced by earthquake (explosions and fires, 
internal flooding caused by pipe breaks, damage on nearby infrastructure, sloshing in the 
SFPs, effects of earthquakes on industries in the vicinity of their sites). 

−  Organisational and technical measures to restore power supply directly from hydropower 

stations. 

−  Possibility to use turbine-driven pumps and atmospheric discharge valves to cool reactor 
core and possibility to operate such equipment manually (without any AC/DC power). 

−  The setting-up of a working group to analyse important factors like accessibility, human 

resources and times available. 

36 

 
 
−  Verification and validation of SAMGs by supporting calculation, analysis and exercises. 

−  Permanent  connection  allowing  alternate  SFP  makeup  without  entering  the  SFP  area 

(Trillo). 

−  Provision  for  containment  cooling  from  the  outside  by  the  annulus  building  ventilation 

(Trillo). 

Safety improvements implemented or planned (non-exhaustive list): 

−  Update site seismic hazard characterization following the most recent IAEA standards. 

−  Analyses  on-going for different improvements: increasing  capacity  of downstream  dams 
spillways, reinforcing of water leak-tightness of building gates, increasing the evacuation 
capacity  in  the  drainage  networks,  improvements  to  galleries  with  potentiality  to  induce 
in-leaks, improving the hydrostatic resistance of seals in galleries connecting to buildings 
containing safety-related equipment. 

−  A specific study on occurrence of tornados in the areas surrounding nuclear facilities 

−  Availability on site of autonomous electricity generating groups. 

−  Additional portable instrumentation in the event of complete loss of the batteries. 

− 

Improvements to the communications systems (on- and off-site) in situations with loss of 
the electrical feed systems; improvements to the lighting for prolonged scenarios. 

−  Design  modifications  required  to  make  available  connection  points  for  autonomous 

electrical and mechanical equipment. 

− 

 Preparation  of  relevant  procedures  and  training  of  personnel  according  to  these 
procedures. 

−  The  setting-up  of  new  on-site  Alternative  Emergency  Management  Centres  (AEMC), 

seismically and flood-resistant at each plant. 

− 

− 

the  setting-up  of  an  Emergency  Support  Centre  (ESC),  common  to  all  the  plants,  with 
back-up equipment located at a central storage and available to be deployed and operated 
by an Intervention Unit ready to act at the sites in 24 hours. 

Installing passive autocatalytic re-combiners (PARs) at those plants that do not have them 
yet. 

− 

Installing a filtered venting system. 

−  Applying  measures  to  prevent  core  damage  sequences  with  high  pressure  in  the  reactor 

and improving the ability to implement containment flooding strategies.  

−  Reinforcement  of  the  electrical  power  supply  to  the  Main  Control  Room  ventilation 

system. 

−  Spent  Fuel  pools:  develop  specific  procedures  to  allow  taking  preventive  measures  to 

assure cooling or water replenishment. 

−  Defining reference dose levels for the personnel intervening in an emergency for all onsite 

intervening personnel during an emergency.  

37 

 
 
5.14. 

SWEDEN 

Recommendations: 

−  To consider carrying out more detailed flooding risk analysis including cliff edge analysis. 
To  assess  plant  vulnerability  against  flooding,  implementation  of  a  refined  external 
flooding PSA could be suggested. 

−  For the Forsmark and the Ringhals sites, to consider studying the combination of high sea 
water  level  and  other  external  phenomena  such  as  swell,  strong  wind  and  organic 
materials. 

−  To implement early warning systems and relevant operating procedures in case of extreme 

weather conditions (which are not in place for all sites). 

−  Reducing risks of common cause failures in Emergency Diesels Generators. 

−  Enhancing the reliability of electric power supply (analysis of robustness of gas turbines 
as  alternate  AC  power,  improving  possibilities  to  refill  the  diesel  tanks  at  diesel  units, 
availability of lube oil, use of diesel generators used for physical protection, increasing the 
number of mobile diesel generators at site, load shedding, etc. 

−  At  Ringhals  an  alternative  cooling  system  for  EDGs  is  prepared  that  might  be  an 

alternative at other units. 

−  Maintaining the level in available water storage tanks close to maximal. 

− 

Installation of pipelines to provide fire water to spent fuel pools. 

−  Qualification  of  mobile  equipment  (and  its  storage)  against  DBE  and  other  external 

hazards.  

−  Consideration of multiple unit events including long term effects. 

−  Ensuring long term performance of the filtered venting system (> 24 hours). 

−  Consideration of natural disasters leading to loss of infrastructure in the SAM. 

−  Concepts to manage large volumes of contaminated water. 

−  Accumulation of hydrogen in rooms or buildings outside the containment. 

−  Qualification  of  instrumentation  (water  level,  temperature  in  the  Spent  Fuel  Pool)  for 

severe accident as well as qualification of the equipment against harsh conditions. 

−  Enhancement  of  the  accident  management  programmes  (SAMGs,  EOPs)  for  all  plant 

states (including spent fuel pools and multi-units events). 

−  EOP  training  and  drills  for  extended  scope  of  the  accident  management  (multiunit 

accidents under conditions of infrastructure degradation). 

Good practices: 

−  After  the  Three  Mile  Island  accident,  the  Swedish  government  decided  that  all  Swedish 
NPPs  should  be  capable  of  withstanding  a  core  melt  accident  without  any  casualties  or 
ground  contamination  of  importance  to  the  population.  This  resulted  in  an  extensive 
backfitting for all Swedish NPPs, including: 

• 

Filtered containment venting through an inerted MVSS with a decontamination 
factor of at least 500. 

38 

 
 
• 

• 

• 

Independent  containment spray  water supply (mobile units and/or firefighting 
system). 

Passive Autocatalytic hydrogen recombiners (PWR). 

Flooded lower drywell in BWR aiming to stabilize ex vessel molten corium. 

−  All  Swedish  BWR  containments  are  inerted  with  nitrogen  since  their  original  design  to 

avoid hydrogen risks. 

−  For  the  most  part,  the  SAM  systems  and  procedures  currently  in  place  were  developed 

during the 1980s and are part of the design bases of the plants.  

−  The communication solution RAKEL. 

−  Capability  to  withstand  loss  of  UHS  scenario  for  long  time  periods  if  water  volumes  in 

various tanks are close to maximal. 

Safety improvements implemented or planned (non-exhaustive list):  

−  More detailed studies for potential improvements regarding mitigation strategies for long 
term severe accident conditions, capability to handle more than one affected unit, analysis 
of destruction of infrastructure, and damage to safety systems and barriers.  

−  Additional  assessment  of  the  containment  integrity  in  the  event  of  a  severe  accident, 

including measures if necessary (all reactors: 2012). 

−  Strategy for long term cooling of a severely damaged core, including physical measures if 

necessary (all reactors: 2012, some measures before 2012). 

− 

Independent emergency core cooling system. (All reactors, studies ongoing). 

−  Change to two phase flow relief valves (Ringhals 1: 2011, Oskarshamn 2: 2013). 

−  Measures to vent incondensable gases from the reactor vessel (Ringhals 1: 2012). 

−  Analysis of the adequacy of emergency control, including upgrade measures, if necessary 

(Oskarshamn 3: 2012, Ringhals 3 & 4: 2012). 

− 

Installation  of  a  new  emergency  control  (Forsmark  1:  2011,  Forsmark  2:  2012, 
Oskarshamn 2: 2013). 

5.15.  UNITED KINGDOM  

Recommendations:  

−  Several  uncertainties  exist  with  regard  to  the  Design  Basis  Earthquake,  which  were 
established by different methodologies for different sites during the 1980s and 1990s. This 
leads  to  ONR’s  “Stress  Test  Finding”  that:  “The  nuclear  industry  should  establish  a 
programme to review the Seismic Hazard Working Party methodology against the latest 
approaches”. 

−  The currently available Design Basis Flooding (DBF) assessments have not accounted for 
some recent tsunami research work, although ONR are content that such work is unlikely 
to significantly affect previous work on maximum credible tsunami heights. 

39 

 
 
−  For  flooding,  there  is  no  satisfactory  evidence  of  capability  of  the  plants  beyond  the 
design  basis.  It  is  recommended  that  the  UK  regulator  considers  providing  a  specific 
programme  for  additional  review  regarding  the  design  basis  approach  and  an  adequate 
response 
identifies  specific  potential  plant 
improvements is recommended. ONR has raised this as findings in the UK report.  

regarding  margin  assessment  and 

−  For  earthquake  and  some  specific  external  hazards,  beyond  design  basis  capability  are 
inferred but not quantified and no specific evidence is provided that margins to cliff edge 
effects  and  potential  specific  improvements  have  been  considered  systematically  for  all 
NPP.  Additional  review  regarding  the  design  basis  approach  and  an  adequate  response 
regarding  margins  assessment  beyond  the  design  basis  and  identification  of  specific 
potential plant improvements. The review team encourages the ONR to establish a strong 
regulatory oversight programme on this matter. 

−  Although  the  reviewers  note  that  the  UK  Chief  Inspector’s  final  report  makes  a 
recommendation to review/revise site-specific flood analyses, ONR is urged to ensure that 
common cause failure modes from flood hazard are comprehensively taken into account 
for all the reactors of a site, in particular regarding the need to share mitigation or mobile 
equipment. 

−  ONR  should  clarify  its  technical  requirement  in  the  implementation  of  the  defence  in 
depth principle regarding flooding, and consider requirements for warning and prevention 
of flooding of the site, protection against flooding of rooms and mitigation, for the whole 
site. 

−  For  AGRs/Magnox,  the  longer  grace  times  should  not  be  used  as  an  argument  for  not 
considering  implementation  of  fixed  hardware  provisions.  The  following  further 
improvements are suggested: 

• 

• 

• 

Inject water into the reactor core as an ultimate means to provide residual heat 
removal  from  the  core  without  use  of  the  boilers  and  identify  the 
means/equipment that would be used, including filtering for AGR/Magnox. 

Stocks of fuel and other consumables. for at least 72h. 

Battery capacity is low compared with other countries and therefore should be 
increased or recharged by additional generators for most of the plants. 

− 

In  accordance  with  the  existing  plans,  the  on-site  emergency  facilities  should  be 
strengthened  in  order  to  be  resistant  against  external  hazards  and  provide  for  working 
conditions  in  case  of  severe  accident.  A  more  comprehensive  assessment  is  also  needed 
regarding  the  occurrence  of  severe  accident  at  multiple  units  and  conditions  of  severely 
damaged infrastructures. 

−  The  need  for  a  backup  control  room  providing  for  shutdown  and  cooldown  to  safe 

condition of the plants should be considered. 

−  Symptom Based Emergency Response Guidelines (SBERGs) and SAGs should be further 
developed  to  cover  fully  all  spectrums  of  accident  scenarios,  including  plant  shutdown 
conditions.  Training  and  exercises  for  implementation  of  the  procedures  should  be 
improved. 

40 

 
 
−  Radiation  conditions  which  may  potentially  develop  on  site  in  case  of  severe  accident, 
possibly  at  several  units,  should  be  more  comprehensively  analysed  and  appropriate 
measures to address them implemented. 

−  The  existing  plans  to  strengthen  hardware  provisions  for  SAM  in  all  reactors,  but  in 
particular  in  Sizewell  B,  are  supported  by  the  review  team.  It  is  advisable  to  take  into 
account the need for operability of newly installed equipment under conditions of extreme 
external hazards and prolonged SBO. Provisions for ensuring sufficient coolant inventory 
in the SFP should be further strengthened by providing e.g. additional delivery of coolant 
from external sources. 

Good practices: 

−  Accident management for gas cooled reactors represent a special case due to their unique 
design  features,  in  particular  absence  of  a  separate  containment  building  and  very  large 
thermal  inertia.  This  large  inertia  provides  comfortable  time  margins  for  performing 
recovery  actions.  Many  severe  accident  challenges  to  confinement  integrity  such  as 
hydrogen explosion, high pressure melt ejection; steam explosion and direct containment 
heating are not present. 

−  The  PSA  that  has  been  produced  for  Sizewell  B  is  a  full  scope  Level  3  PSA.  The  PSA 
addresses  all  modes  of  operation  of  the  plant  (full  power,  low  power  and  shutdown 
modes), internal initiating events, and internal and external hazards. 

−  Strong safety features for NPPs in the UK are the different independent and autonomous 
systems and the diverse back-up AC power Diesel or Petrol Driven Generators and pumps 
or steam driven pumps present on any site, the Gasturbines at Magnox operating reactors 
and the four independent EDG’s at Sizewell B. At Sizewell B the Reserve Ultimate Heat 
Sink system and the two steam-driven emergency feed deserve also to be mentioned. 

−  Approximately  ten  years  ago  the  licensees  established  a  number  of  beyond  design  basis 
containers that contain a range of equipment and materials that could be beneficial when 
responding  to  a  beyond  design  basis  accident.  These  containers  are  located  remotely 
offsite at a central UK location, available to be transported to an affected site within a ten 
hour timeframe following declaration of an off-site nuclear emergency. All containers and 
their contents are maintained regularly, and their deployment has been exercised. 

Safety improvements implemented or planned (non-exhaustive list):  

−  For  Sizewell  B,  it  was  confirmed  during  the  country  visit  that  the  licensee  will  install  a 
filtered  containment  venting  system  and  passive  autocatalytic  hydrogen  recombiners  as 
part  of  SAM  improvement  measures.  In  addition,  it  will  consider  a  flexible  means  of 
injecting  water  into  the  containment  using  portable  external  equipment.  Some  other 
specific  enhancements  are  already  being  considered,  for  example  the  provision  of  a 
hardened Emergency Control Centre at Sizewell B. 

−  Finally, further studies on SAM are planned in the following areas: 

• 

• 

How the pilot PSA studies (Level 2 PSA; Fire PSA; Shutdown PSA) and the 
insights from them are taken forward across the AGRs fleet. 

Further resilience enhancements to communications equipment and associated 
critical supplies. 

41 

 
 
• 

• 

Potential  explosive  hazard  arising  from  the  production  of  Carbon  monoxide 
(CO) for AGRs during a severe accident. 

AGR pressure vessel basemat melt through in severe accident conditions. 

6. 

SUMMARIES OF NEIGHBOURING COUNTRIES' PEER REVIEWS 

6.1. 

SWITZERLAND  

Recommendations:  

− 

− 

It is recommended that the regulator assesses the opportunity of requiring more reliance 
on passive systems for hydrogen management for severe accident conditions.  

It  is  recommended  that  the  regulator  considers  further  studies  on  the  hydrogen 
management for the venting systems. 

Good practices:  

−  The review team has recognized the significant efforts carried out to update in depth the 
seismic hazard assessment in Switzerland, which would lead to identification of possible 
safety  improvements.    It  is  based  on  a  probabilistic  seismic  hazard  analysis  and  is 
considered  to  be  ’state  of  the  art’  by  the  Regulator.  It  includes  a  recently  updated 
paleoseismological data-base and uses a solid scientific basis.  

−  The peer review team recognises as good practice the recent creation of a flooding-proof 
and  earthquake-resistant  external  storage  facility  at  Reitnau.  The  storage  facility  houses 
various  operational  resources  for  emergencies,  which  are  readily  available  and  can  be 
supplied to the required location within reasonably short time frames. 

−  The safety train concept and a strong defence in depth contribute to the robustness of the 
plant. There are 3  independent  paths to  bring and maintain the plant in a safe  shutdown 
state, one being fully autonomous for at least 10 hours. The number of safety layers for 
power supply is significant and diverse options are available. An external storage was set 
up in 2011 and can provide in a timely manner additional diesel generators. 

−  Three sites have an alternate cooling source consisting of specially protected deep-water 
wells that would provide water in the event of the loss of the primary ultimate heat sink. 

−  During the peer review process, the following strong points have been identified: 

• 

• 

• 

• 

• 

• 

The ENSI issued a comprehensive report on lessons learned after Fukushima.  

SAM has been addressed in national regulations and the main components of 
SAM were in place before the Fukushima accident,  

SAMGs are available for both power and shutdown states, 

Effective AM strategies are available in case of prolonged SBO. 

Long-term scenarios are covered in procedural guidance’s. 

SFPs outside the containments are addressed by SAMGs. 

42 

 
 
•  Multi-unit events (for Beznau NPP, the only site with more than one unit) and 
arrangements have been tested repeatedly even before the Fukushima accident. 

• 

• 

• 

Filtered containment venting, with active and passive activation.  

Emergency  Control  Rooms  are  protected  against  external  events,  including 
filtered  air  supplies.  Manual  actions  can  be  performed  from  radiologically 
protected areas. 

Re-criticality  in  the  SFP  is  unlikely.  Possibility  for  injection  of  non-borated 
water,  e.g.  with  fire  pumps  through  prepared  connections.  6  tons  of  boron  is 
available for SAM. 

Safety improvements implemented or planned (non-exhaustive list): 

−  Targeted  back-fitting  measures  to  improve  the  seismic  resistance  of:  the  supporting 
structures for cables and the control stations in the main control room (Gösgen NPP), the 
SFP  cooling  at  Beznau  NPP  and  Mühleberg  NPP,  and  the  installation  of  a  new  set  of 
EDGs that are robust against earthquake at Beznau NPP. 

−  Back-fitting  of  two  physically  separated  connections  for  the  external  spent  fuel  pool 

supply at all the NPPs (without the need to enter the SFP area). 

−  At  Beznau  NPP,  additional  independent  flood  protected  spent  fuel  pool  cooling  system 
with  coolant  supply  from  the  protected  special  emergency  well  and  additional  injection 
means into the SFPs via an existing alternative pool cooling system, and via a new flood 
protected pool cooling system. 

−  At  Gösgen  NPP,  building  of  a  flood  protection  wall  to  prevent  water  ingress  through  a 
breach in an embankment, and preparation of a shut-off bulkhead for access via the power 
plant  road.  Mühleberg  NPP  plans  to  install  a  diverse  flood  protected  SFP  cooling  water 
system. 

−  For Gösgen NPP the following improvements have been implemented:  

• 

• 

• 

• 

Introduction of an automatic advance flooding alarm. 

Additional  sealing  of  building  shells,  air  inlets  and  doors,  etc.,  of  buildings 
with equipment used for the safe shutdown of the plant. 

Preparation for the erection of dam bulkheads. 

Installation of ‘flood valves’ to seal ventilation intakes. 

−  For Mühleberg NPP the following improvements have been implemented:  

• 

• 

Provision  of  mountable  flood  protection  walls  for  protection  against  flooding 
of the auxiliary cooling water pumps in the pump building, and enhancement 
of the relevant operating instructions. 

Provision of mobile pumps to inject water into the diversified heat sink intake 
structure. 

43 

 
 
• 

• 

Implementation  of  an  additional  injection  option  (intake  shaft)  into  the 
diversified heat sink intake structure. 

Back-fitting  of  three  special  vertical  pipes  on  top  of  the  diversified  heat  sink 
intake structure to ensure the cooling water supply for the diversified heat sink. 

−  To  increase  the  number  of  options  available  for  SFP  cooling,  all  sites  will  also  have  to 
back-fit a physically separated additional feed for the pools (used by mobile means from 
outside the building). 

− 

In three plants, at least one medium-sized mobile AM emergency power unit (at least 120 
kW / 150 kVA) is available locally. Since the end of October 2011, two large mobile units 
(approx. 890 kW) have been available at Beznau NPP. 

6.2. 

UKRAINE 

Recommendations:  

−  The seismic evaluations for some parts of the equipment, piping, buildings and structures 
important  to  safety  are  not  yet  completed.  Some  additional  seismic  safety  upgrading 
measures  are  envisaged,  but  not  implemented  yet.  The  peer  review  recommends 
monitoring in a systematic way the implementation of the upgrading measures in order to 
assure timely completion as part of the Comprehensive safety improvement programme.  

−  A special attention should be paid for defining vulnerability of the plant in case of beyond 
design basis tornado (in terms of potential loss of essential service water). Safety margins 
with respect to extreme wind and extreme snow should be evaluated too. The peer review 
recommends considering monitoring the fulfilment of additional analyses of the threat to 
the essential service water system due to the tornado impact as well as the evaluation of 
emergency  arrangements  with  respect  to  the  personnel  access  to  sites  in  severe  weather 
conditions. 

−  The improvement of makeup possibilities to primary circuit, to the SGs, and to the spent 
fuel  ponds  in  case  of  SBO  and  LUH  events  is  being  considered.  The  deployment  of 
mobile diesel and pumping (MDGPU) unit has to be further analysed in detail. The peer 
review recommends that the regulator considers monitoring resolution of these proposals.  

−  Concerning SAM the peer review recommends the following topics for consideration by 

the Ukrainian regulator: 

• 

• 

• 

Demonstration, with a high degree of confidence, that the key functions needed 
for SAM can be achieved. In particular, provisions against cliff-edge effects on 
accident  progression  should  be  addressed  in  priority  (hydrogen  management, 
control,  reliability  of  RCS  depressurization  function  in  severe  accident 
condition). 

A  strategy  and  program  for  the  qualification  of  equipment  needed  in  severe 
accident conditions should be implemented. 

The  risk  induced  simultaneously  by  reactor  and  SFP  in  case  of  a  severe 
accident should be assessed. 

44 

 
 
• 

• 

• 

The analysis of SFP accident in various configurations in order to underwrite 
EOP and SAMGs, the robustness of the means to cool the SFP even after core 
melt should be improved. If SFP is inside the containment, a means to cool the 
SFP  should  be  ensured  even  if  some  internal  structures  (pipes)  in  the 
containment have been damaged by hydrogen combustion. 

Further investigation of the habitability of MCRs and ECRs in case of a severe 
accident  as  well  as  enhanced  seismic  capabilities  for  the  building  hosting  the 
crisis  centre  should  be  assessed.  The  schedule  for  hardware  and  procedures 
implementations should stay under strict control of the regulator. 

For  site  with  several  units  it  should  be  verified  in  details  the  feasibility  of 
immediate actions required to avoid core melt, prevent large release, and avoid 
site evacuation for a disaster affecting more than one unit at a particular site. 

Good practices:  

−  High  level  of  redundancy  of  SSCs  and  power  supply  (DGs)  which  offers  many 
possibilities  and  flexibility  for  accident  management;  some  extensive  additional  safety 
upgrades to the original design are implemented to prevent severe accidents.  

−  The risk of common mode failure is being addressed through additional mobile equipment 

that should allow for quick connection and should be stored in a safe area. 

−  Some prompt actions already implemented: mobile DG for Chernobyl NPP (ChNPP), set 

of targeted emergency exercises conducted at all NPPs, including ChNPP. 

− 

In addition, emergency exercises on long term SBO type of scenarios were conducted at 
all  Ukrainian  NPPs.  Upon  their  results,  measures  were  identified  to  improve  on-site 
emergency response taking into account Fukushima-related phenomena. 

Safety improvements implemented or planned (non-exhaustive list):  

The  following  measures  are  envisaged 
Improvement Program for Ukrainian NPPs”: 

in 

the  “Comprehensive  (Integrated)  Safety 

−  Complete  equipment  seismic  qualification  for  0.1g  and  additional  seismic  investigations 
of  NPP  sites  and  assurance  of  robustness  of  equipment,  piping,  buildings  and  structures 
important to safety to seismic impact >0.1g. 

−  Assurance of operability of essential service water consumers under loss of water in spray 

ponds of operating plants as a result of tornado. 

− 

− 

Increase  the  discharge  time  of  batteries  and  restoration  of  power  supply  to  stationary 
makeup pumps from a Mobile Diesel Generator (MDG). 

Improve  the  emergency  makeup  to  SG,  water  injection  into  SG  from  fire  trucks  and 
MDGPU  (Mobile  Diesel  Generator  and  Pumping  Units),  as  well  as  injection  of  borated 
water  into  the  primary  circuit  from  MDGPU,  restoration  of  power  supply  to  stationary 
makeup pumps from a MDG, and water injection into the SFP from independent MDGPU 
or from the fire extinguishing system.  

−  Development and Implementation of SAMG at WWER 440 and 1000 Units. 

45 

 
 
−  Preservation  of  the  containment  integrity  if  there  is  interaction  with  corium  (active  core 
melt)  at  the  ex-vessel  phase  of  severe  accident  including  implementation  of  H2 
concentration reduction measures for BDBA situations. 

− 

Implementation  of  the  filtered  containment  venting  system  for  all  WWER-1000  and 
WWER-440 units. 

46 

 
 
GLOSSARY 

AC  
AEFS 
AEMC 
AGR 
AFW 
AM(P) 
APOP 
BDB(A) 
BDBE 
BWR 
CANDU 
CDF 
CNCAN 
CSN 
CVA 
DBE 
DBF 
DC  
DG  
EC  
ECC 
ECR 
EDF NGL 
EDG 
EDMG 
EMC 
EMS 
ENSI 
ENSREG 
EOP 
EPR 
EPS  
FANC 
FARN 
GRS 
HCLPF 
FANC 
IAEA 
I&C 
LOOP 
LUHS 
MCCI 
MCE 
MCR 
MSSV 
MDGPU 

Alternating Current 
Additional Emergency Feedwater System 
Alternative Emergency Management Centres  
Advanced Gas Cooled Reactor 
Auxiliary Feedwater 
Accident Management (Programme) 
Abnormal plant operating procedures 
Beyond Design Basis (Accident) 
Beyond Design Basis Earthquake 
Boiling Water Reactor 
Canada Deuterium Uranium (Pressurised Heavy Water) Reactor 
Core Damage Frequency  
Romanian National Commission for Nuclear Activities Control 
Nuclear Safety Council (Consejo de Seguridad Nuclear), Spain 
Auxiliary steam system 
Design Basis Earthquake 
Design Basis Flood 
Direct Current 
Diesel Generator 
European Commission 
Emergency Control Centre 
Emergency Control Room 
EDF Energy Nuclear Generation Ltd 
Emergency Diesel Generator 
Extensive Damage Mitigation Guidelines 
Emergency Management Center 
Emergency Makeup System 
Swiss Federal Nuclear Safety Inspectorate 
European Nuclear Safety Regulators Group 
Emergency Operating Procedure 
Evolutionary Power Reactor 
Emergency Power Supply 
Federaal Agentschap voor Nucleaire Controle, BE 
Nuclear Rapid Response Force 
The Gesellschaft für Anlagen- und Reaktorsicherheit, DE 
High Confidence of Low Probability of Failure  
Federal Agency for Nuclear Control (in Belgium) 
International Atomic Energy Agency 
Instrumentation and Control 
Loss Of Offsite Power 
Loss of Ultimate Heat Sink 
Molten Core-Concrete Interaction 
Maximum Calculated Earthquake 
Main Control Room 
Main Steam Safety Valves 
Mobile Diesel and Pumping Unit 

47 

 
 
 
NCM 
NRC 
NPP 
NVR 
ONR 
PAR 
PCC 
PGA 
PMF 
PSHA 
PSA 
PSR 
PWR 
RCIC 
RCP 
RCS 
RLE 
RPV 
RWST 
SAM 
SAMG 
SBERG 
SBO 
SCA 
SDG 
SG  
SGTR 
SFP 
SFSF 
SPSA 
SSC 
STUK 
SWHP 
UHS 
VVER 
WANO 
WENRA 

Non-conventional Means 
(United States) Nuclear Regulatory Commission 
Nuclear Power Plant 
Nuclear Safety Rule 
Office for Nuclear Regulation, UK 
Passive Autocatalytic Recombiner 
Protected Command Center 
Peak Ground Acceleration 
Probable Maximum Flood 
Probabilistic Seismic Hazard Analysis 
Probabilistic Safety Analysis 
Periodic Safety Review 
Pressurised Water Reactor 
Reactor Core Isolation Cooling 
Reactor Coolant Pump 
Reactor Coolant System 
Review Level Earthquake 
Reactor Pressure Vessel 
Refuelling Water Storage Tank 
Severe Accident Management 
Severe Accident Management Guidelines 
Symptom Based Emergency Response Guidelines 
Station Blackout 
Secondary Control area 
Stand-by Diesel Generator 
Steam Generator 
Steam Generator Tube Rupture 
Spent Fuel Pool / Pit 
Spent Fuel Storage Facility 
Seismic Probabilistic Safety Assessment 
Structures, Systems and Components 
Radiation and Nuclear Safety Authority (Finland) 
Seismic Hazard Working Party  
Ultimate Heat Sink 
(Russian) Water Water Energetic Reactor 
World Association of Nuclear Operators 
Western European Nuclear Regulators’ Association

48 

 
 
ANNEX 1: SUMMARY TABLE 

Issue no.  Description (“X” in the table where these issues or good practices are applicable) 

I1 

I2 
I3 
I4 
I5 
I6 
I7 

I8 

I9 

I10 

GP1 

GP2 

GP3 

GP4 

GP5 

Other 
issues 

External hazard safety cases corresponding to an exceedance probability of less than once in 10 000 years should be used (I1a: for earthquakes; 
I1b: for flooding). 
A DBE corresponding to a minimum peak ground acceleration of 0.1 g should be used. 
Means needed to fight accidents should be stored in places adequately protected against external events. 
On-site seismic instrumentation should be installed. 
Time for restoration of the safety functions in case of loss of all electrical power and/or ultimate heat sink is less than 1 hour. 
Emergency Operating Procedures not covering all plant states (full power to shutdown states) 
Severe Accident Management Guidelines not covering all plant states (full power to shutdown states) 
Passive measures to prevent hydrogen (or other combustible gasses) explosions in case of Severe Accident not in place (such as Passive 
Autocatalytic Recombiners or other relevant alternative)  
Filtered Venting Systems not in place  
A backup Emergency Control Room not available, in case the Main Control Room becomes inhabitable as a consequence of the radiological 
releases of a severe accident, of fire in the Main Control Room or due to extreme external hazards. 
Existence of alternative and fully independent ultimate heat sink (good practice). 
Additional layer of safety systems fully independent from the normal safety systems, located in areas well protected against external events (for 
instance bunkered systems or hardened core of safety systems) (good practice). 
Additional Diesel Generators (or Combustion Turbines) physically separated from the normal diesel generators and devoted to cope with 
Station Black-Out, external events or severe Accident situations already installed (good practice) 
Mobile equipment especially Diesels Generators devoted to cope with Station Black-Out, external events or severe accident situations are 
already available (good practice) 
Additional on-site emergency control centre, from which the emergency response activities can be coordinated, should available and adequately 
protected against radiological and extreme natural hazards (good practice). 

Site / unit specific issue referred in the text of the Staff Working Document. 

49 

 
 
  
The legend above summarises the recommendations made by the peer reviews to the national regulators for consideration to improve the safety of 
nuclear power plants as well as good practises identified. The table below connects those recommendations as well as the good practices directly to 
each reactor of each NPP in the EU. In order to assess the full applicability of each recommendation a backward reference should be made to the 
relevant chapter of this working document, as well as the national reports and the individual facility reports available on www.ensreg.eu.  

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15/02/1975 

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433 

01/12/1975 

36 

433 

01/10/1982 

29 

1006 

01/07/1985 

26 

1039 

01/10/1975 

36 

962 

01/06/1983 

28 

1008 

01/09/1985 

26 

1046 

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PWR 

PWR 

PWR 

PWR 

PWR 

PWR 

PWR 

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23 

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50 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                                                            
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CZ 

Dukovany 

PWR (VVER-
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PWR (VVER-
440/213) 

PWR (VVER-
440/213) 

PWR (VVER-
440/213) 

PWR (VVER-
440/213) 

1 

03/05/1985 

26 

427 

X 

X1  X1 

X1 

X 

X 

2 

21/03/1986 

25 

427 

X 

X1  X1 

X1 

X 

X 

3 

20/12/1986 

25 

471 

X 

X1  X1 

X1 

X 

X 

4 

19/07/1987 

24 

427 

X 

X1  X1 

X1 

X 

X 

Temelin 

PWR (VVER-
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1 

10/06/2002 

9 

963 

X 

PWR (VVER-
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2 

18/04/2003 

8 

963 

X 

FI 

Loviisa 

Olkiluoto 

PWR 

PWR 

BWR 

1 

2 

1 

09/05/1977 

34 

488 

05/01/1981 

30 

488 

X 

X 

10/10/1979 

32 

885 

X1 

X1 

X 

X 

X 

51 

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Belleville 

PWR-1300 

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01/06/1988 

24 

1310 

X 

X 

01/01/1989 

23 

1310 

X 

X 

Blayais 

PWR-900-CPY-
CP1 

1 

01/12/1981 

30 

910 

X 

X 

PWR-900-CPY-
CP1 

PWR-900-CPY-
CP1 

PWR-900-CPY-
CP1 

Bugey 

PWR-900-CPO 

PWR-900-CPO 

PWR-900-CPO 

PWR-900-CPO 

Cattenom 

PWR-1300 

2 

01/02/1983 

29 

910 

X 

X 

3 

14/11/1983 

28 

910 

X 

X 

4 

01/10/1983 

28 

910 

X 

X 

2 

3 

4 

5 

1 

01/03/1979 

33 

910 

X 

X 

01/03/1979 

33 

910 

X 

X 

01/07/1979 

33 

880 

X 

X 

03/01/1980 

32 

880 

X 

X 

01/04/1987 

25 

1300 

X 

X 

X 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

52 

X1 

X1 

X1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

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1 

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1 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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PWR-1300 

PWR-1300 

PWR-1300 

Chinon 

PWR-900-CPY-
CP2 

PWR-900-CPY-
CP2 

PWR-900-CPY-
CP2 

PWR-900-CPY-
CP2 

Chooz 

PWR-1500 N4 

PWR-1500 N4 

Civaux 

PWR-1500 N4 

PWR-1500 N4 

t
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2 

3 

4 

B-
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B-
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B-
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B-
4 

B-
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B-
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1 

2 

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24 

1300 

01/02/1991 

21 

1300 

01/01/1992 

20 

1300 

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X 

X 

X 

X 

X 

X 

X 

X 

01/02/1984 

28 

905 

X 

X 

01/08/1984 

28 

905 

X 

X 

04/03/1987 

25 

905 

X 

X 

01/04/1988 

24 

905 

X 

X 

15/05/2000 

12 

1500 

X 

X 

X 

29/09/2000 

12 

1500 

X 

X 

X 

29/01/2002 

10 

1495 

23/04/2002 

10 

1495 

X 

X 

a
1
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b
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2
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3
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4
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5
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6
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7
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5
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X1 

X1 

53 

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X 

X 

X 

X 

X 

X 

X 

X 

X 

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PWR-900-CPY-
CP2 

1 

02/04/1984 

28 

915 

X 

X 

PWR-900-CPY-
CP2 

PWR-900-CPY-
CP2 

PWR-900-CPY-
CP2 

2 

01/04/1985 

27 

915 

X 

X 

3 

10/09/1984 

28 

915 

X 

X 

4 

11/02/1985 

27 

915 

X 

X 

Dampierre 

PWR-900-CPY-
CP1 

1 

10/09/1980 

32 

890 

X 

X 

PWR-900-CPY-
CP1 

PWR-900-CPY-
CP1 

PWR-900-CPY-
CP1 

2 

16/02/1981 

31 

890 

X 

X 

3 

27/05/1981 

31 

890 

X 

X 

4 

20/11/1981 

30 

890 

X 

X 

Fessenheim 

PWR-900-CPO 

PWR-900-CPO 

Flamanville 

PWR-1300 

1 

2 

1 

01/01/1978 

34 

880 

X 

X 

X 

01/04/1978 

34 

880 

X 

X 

X 

01/12/1986 

25 

1330 

X 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

54 

X1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

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1 

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1 

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1 

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Golfech 

PWR-1300 

PWR-1300 

t
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2 

1 

2 

09/03/1987 

25 

1330 

X 

01/02/1991 

21 

1310 

X 

X 

04/03/1994 

18 

1310 

X 

X 

Gravelines 

PWR-900-CPY-
CP1 

1 

25/11/1980 

31 

910 

X 

X 

PWR-900-CPY-
CP1 

PWR-900-CPY-
CP1 

PWR-900-CPY-
CP1 

PWR-900-CPY-
CP1 

PWR-900-CPY-
CP1 

2 

01/12/1980 

31 

910 

X 

X 

3 

01/06/1981 

31 

910 

X 

X 

4 

01/10/1981 

30 

910 

X 

X 

5 

15/01/1985 

27 

910 

X 

X 

6 

25/10/1985 

26 

910 

X 

X 

Nogent 

PWR-1300 

PWR-1300 

Paluel 

PWR-1300 

1 

2 

1 

24/02/1988 

24 

1310 

X 

X 

01/05/1989 

23 

1310 

X 

X 

01/12/1985 

26 

1330 

X 

X 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

55 

X1 

X1 

X1 

X1 

X1 

X1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

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1 

1 

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1 

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PWR-1300 

PWR-1300 

PWR-1300 

Penly 

PWR-1300 

PWR-1300 

St. Alban 

PWR-1300 

PWR-1300 

St. Laurent 

PWR-900-CPY-
CP2 

PWR-900-CPY-
CP2 

t
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2 

3 

4 

1 

2 

1 

2 

B-
1 

B-
2 

01/12/1985 

26 

1330 

X 

X 

01/02/1986 

26 

1330 

X 

X 

01/06/1986 

26 

1330 

X 

X 

01/12/1990 

21 

1330 

X 

X 

01/11/1992 

19 

1330 

X 

X 

01/05/1986 

26 

1335 

01/03/1987 

25 

1335 

X 

X 

01/08/1983 

29 

915 

X 

X 

01/08/1983 

29 

915 

X 

X 

Tricastin 

PWR-900-CPY-
CP1 

1 

01/12/1980 

31 

915 

X 

X 

X 

PWR-900-CPY-
CP1 

PWR-900-CPY-
CP1 

2 

01/12/1980 

31 

915 

X 

X 

X 

3 

11/05/1981 

31 

915 

X 

X 

X 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

56 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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PWR-900-CPY-
CP1 

4 

01/11/1981 

30 

915 

X 

X 

X 

X1 

1 

X 

1 

DE 

Biblis 

PWR 

A 

26/02/1975 

37 

1167 

PWR 

B 

31/01/1977 

35 

1240 

Brokdorf 

PWR 

22/12/1986 

25 

1410 

Brunsbuettel 

BWR 

09/02/1977 

35 

771 

Emsland 

PWR 

20/06/1988 

24 

1329 

Grafenrheinfeld 

PWR 

17/06/1982 

30 

1275 

X 

Grohnde 

PWR 

01/02/1985 

27 

1360 

Gundremmingen 

BWR 

B 

19/07/1984 

28 

1284 

X 

BWR 

C 

18/01/1985 

27 

1288 

X 

Isar 

Kruemmel 

BWR 

PWR 

BWR 

1 

2 

21/03/1979 

33 

878 

09/04/1988 

24 

1410 

28/03/1984 

28 

1346 

X 

X 

X 

X 

X 

X 

X1 

X 

X 

X1 

X1 

X1 

X1 

X1 

X 

X 

X1 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

57 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

1 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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Neckarwestheim 

PWR 

PWR 

Philippsburg 

BWR 

Unterweser 

HU 

Paks 

PWR 

PWR 

PWR (VVER-
440/213) 

PWR (VVER-
440/213) 

PWR (VVER-
440/213) 

PWR (VVER-
440/213) 

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01/12/1976 

35 

785 

15/04/1989 

23 

1310 

26/03/1980 

32 

890 

18/04/1985 

27 

1402 

t
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n
U

1 

2 

1 

2 

06/09/1979 

33 

1345 

X 

X 

1 

10/08/1983 

28 

470 

X 

2 

14/11/1984 

27 

473 

X 

3 

01/12/1986 

25 

473 

X 

4 

01/11/1987 

24 

473 

X 

X 

X1 

X 

X 

X1 

X 

1 

1 

1 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

LT 

Ignalina 

LWGR (RBMK 
1500) Permanent 
shutdown 

1 

31/12/1983 

- 

- 

X 

X 

1 

X 

X 

58 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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LWGR (RBMK 
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2 

01/08/1987 

- 

- 

X 

1 

X 

X 

NL 

Borssele 

PWR 

26/10/1973 

38 

487 

X 

X1  X1  X1  X1 

X 

X 

X 

X 

1 

X 

1 

02/12/1996 

15 

650 

X 

X 

 X1 

X 

X1 

X1 

X 

X 

X 

X 

2 

31/10/2007 

4 

650 

X 

X 

X 

X 

X1 

X1 

X 

X 

X 

RO 

Cernavoda 

SK 

Bohunice 

PHWR 
(CANDU-6) 

PHWR 
(CANDU-6) 

PWR (VVER-
440/213) 

PWR (VVER-
440/213) 

3 

14/02/1985 

27 

505 

4 

18/12/1985 

26 

505 

X1 

X1 

X 

X1 

X1 

X 

X1 

X1 

X 

X1 

X1 

X 

X1 

X1 

1 

1 

1 

1 

X 

X 

X 

X 

1 

1 

1 

1 

X 

Mochovce 

PWR (VVER-
440/213) 

1 

29/10/1998 

13 

470 

X 

PWR (VVER-
440/213) 

2 

11/04/2000 

12 

470 

X 

SI 

Krsko 

PWR 

01/01/1983 

28 

666 

X 

X 

X 

59 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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Almaraz 

Asco 

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r
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u
C

]
e
w
M

[

01/09/1983 

28 

1008 

01/07/1984 

27 

956 

10/12/1984 

27 

996 

31/03/1986 

25 

992 

t
i
n
U

1 

2 

1 

2 

?
d
e
t
i
s
i
v
e
t
i
S

X 

X 

e
p
y
T

PWR 

PWR 

PWR 

PWR 

Cofrentes 

BWR/6 MK-3 

11/03/1985 

26 

1064 

BWR/4 MK-1 

11/05/1971 

40 

446 

S.Maria de 
Garona 

Trillo 

Vandellos 

SE 

Forsmark 

PWR 

PWR 

BWR 

BWR 

BWR 

1 

2 

1 

2 

3 

1 

2 

3 

06/08/1988 

23 

1000 

X 

08/03/1988 

23 

1045 

10/12/1980 

31 

978 

07/07/1981 

30 

990 

X 

X 

18/08/1985 

26 

1170 

X 

06/02/1972 

39 

473 

01/01/1975 

36 

638 

15/08/1985 

26 

1400 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

60 

Oskarshamn 

BWR 

BWR 

BWR 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X1 

X 

X1 

X1 

X1 

X 

X1 

X1 

X1 

X1 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

1 

1 

1 

1 

1 

1 

1 

1 

X 

X 

X 

X 

X 

X 

1 

1 

1 

1 

1 

1 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
y
r
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t
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e
p
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T

t
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U

Ringhals 

UK 

Dungeness B 

Hartlepool 

Heysham 1 

Heysham 2 

BWR 

PWR 

PWR 

PWR 

AGR 

AGR 

AGR 

AGR 

AGR 

AGR 

AGR 

AGR 

1 

2 

3 

4 

1 

2 

1 

2 

1 

2 

1 

2 

?
d
e
t
i
s
i
v
e
t
i
S

X 

X 

X 

X 

l
a
i
c
r
e
m
m
o
c

f
o
t
r
a
t
S

n
o
i
t
a
r
e
p
o

f
o

s
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t
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r
u
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n
o
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t
a
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e
p
o

y
t
i
c
a
p
a
c

t
e
n
t
n
e
r
r
u
C

]
e
w
M

[

01/01/1976 

35 

855 

01/05/1975 

36 

813 

09/09/1981 

30 

1051 

21/11/1983 

28 

935 

01/04/1985 

26 

520 

01/04/1989 

22 

520 

01/04/1989 

22 

595 

01/04/1989 

22 

595 

01/04/1989 

22 

585 

01/04/1989 

22 

575 

01/04/1989 

22 

620 

01/04/1989 

22 

620 

X 

X 

a
1
I

b
1
I

2
I

3
I

4
I

5
I

6
I

7
I

8
I

9
I

0
1
I

1
P
G

2
P
G

3
P
G

4
P
G

5
P
G

?
s
e
u
s
s
i

r
e
h
t
O

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

1 

1 

1 

1 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

2 EOPs and SAMGs needs further development to be in line with international standards – Improvement planned. 

61 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                                                            
y
r
t
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u
o
c

e
t
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S

e
p
y
T

t
i
n
U

Hinkley Point B 

AGR 

AGR 

Hunterston B 

AGR 

Oldbury 

Sizewell B 

Torness 

Wylfa 

AGR 

GCR 

GCR 

PWR 

AGR 

AGR 

GCR 

GCR 

1 

2 

1 

2 

1 

2 

1 

1 

2 

1 

2 

l
a
i
c
r
e
m
m
o
c

f
o
t
r
a
t
S

n
o
i
t
a
r
e
p
o

f
o

s
r
a
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y

t
n
e
r
r
u
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n
o
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t
a
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p
o

y
t
i
c
a
p
a
c

t
e
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t
n
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u
C

]
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w
M

[

?
d
e
t
i
s
i
v
e
t
i
S

02/10/1978 

33 

410 

27/09/1976 

35 

430 

06/02/1976 

35 

430 

31/03/1977 

34 

430 

31/12/1967 

44 

217 

30/09/1968 

43 

217 

22/09/1995 

16 

1188 

X 

25/05/1988 

23 

600 

03/02/1989 

22 

605 

01/11/1971 

40 

490 

03/01/1972 

39 

490 

a
1
I

b
1
I

2
I

3
I

4
I

5
I

6
I

7
I

8
I

9
I

0
1
I

1
P
G

2
P
G

3
P
G

4
P
G

5
P
G

?
s
e
u
s
s
i

r
e
h
t
O

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X2 

X 

X 

X 

X 

X 

X 

X1 

X1 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

62