Going deeper into siting

Published: November 1, 2012
  • Mailiao cryogenic tanks (Taiwan)-soil improvement by stone column foundations – photo P. Debauche (Tractebel Engineering)
  • Mailiao cryogenic tanks (Taiwan)-Pierre Debauche on site – photo Tractebel Engineering
  • Nuclear site selection in Jordan. Erna Van Echelpoel with Prof. Dr. Khalil Ibrahim (Hashemite University of Jordan) – photo Tractebel Engineering
  • Nuclear site selection in Jordan-drilling – photo Tractebel Engineering
  • Jordan nuclear site selection-geotechnical investigations – photo Tractebel Engineering
  • Cameroon site selection for LNG export - Pierre Debauche on the way of Lolabé village – photo Tractebel Engineering
  • Cameroon site selection for LNG export - Pierre Debauche on the way of Mboro village – photo Tractebel Engineering
  • Cameroon site selection for LNG export - example of site characterisation – design Tractebel Engineering
  • Site investigations for Mundra LNG import terminal (India) (FEED studies-2009) photo P. Debauche (Tractebel Engineering)

 

Natural disasters are regular reminders of why Site Assessment is mandatory when building high-risk installations; nuclear reactors and LNG terminals in particular. And why Tractebel Engineering (GDF SUEZ) is a valuable partner in this specialised field.

All part of the service

Evaluating earthquake risk is a key aspect of siting. So is assessing flood or tsunami threats. Then there are landslides, subsurface instability, karsts, hydrogeology and active volcanism – on top of meteorological and human induced hazards. Working around the world, such assessments are just a part of what our geology and geotechnical specialists do every day. Find out about Tractebel Engineering’s siting services

More than just a pretty site

Good site assessment means looking beyond and below positive surface attributes. It also relies on many different competences to produce all the reports required by regulating bodies. So what should developers and clients be looking for in a siting studies partner?

Exciting sites


All part of the service

Evaluating earthquake risk is a key aspect of siting. So is assessing flood or tsunami threats. Then there are landslides, subsurface instability, karsts, hydrogeology and active volcanism – on top of meteorological and human induced hazards. Working around the world, such assessments are just a part of what our geology and geotechnical specialists do every day.

Probalistic Seismic Hazard Analysis (PSHA)

PSHA is standard when evaluating sites for NPP and LNG terminals. These installations cannot fully resist the forces of a serious surface rupture, so international regulations stipulate that you cannot site close to a known active fault (one that has seen activity in the last 500,000 years!). Even when sites are a good distance away from a fault, we still review historic geological data and records for traces of past seismic activity. Cross hole tests (sonic waves sent between 2 drilled boreholes are measured to see if the ground will amplify a quake or not), are also used to check that the Peak Ground Acceleration (PGA – movement during a quake) is low enough for a reactor or LNG tank to withstand.

Water – an essential hazard

LNG terminals and NPP (which need vast amounts of cooling water), are commonly situated by the sea. When siting this calls for near-shore investigations; assessing the impact of serious flooding and tsunamis risk. As many more LNG terminals are built on land reclaimed from the sea, poor soil quality and the high risk of soil liquefaction are also concerns.

All round protection

International codes require that site environments are protected – the plant footprint as well as the surrounding area. Even if a site area seems to be all sand and rocks, the process of evaluating impact on any flora and fauna is compulsory. The security of nearby population centres is also assessed. But the installations need a secure environment too. Potential human induced risks (nearby hazardous industries, military or aircraft activity), the geomorphology of a site and common geographic hazards like flash floods, evaporation of water supplies, landslides and more are also considered.

Going in deeper

Key to engineering an installation on reclaimed land or any site where soil conditions may be less than ideal is the geotechnical characterisation of the site. Drilling at intervals across the whole site in combination with geophysical measurements (using aerial photography) allows experts to read the morphology of a site and ensure solid foundation designs for the plants.


More than just a pretty site

Good site assessment means looking beyond and below positive surface attributes. It also relies on many different competences to produce all the reports required by regulating bodies. So what should developers and clients be looking for in a siting studies partner?

Speed is of the essence

For investors, the pace of development of an installation has cost implications. Yet, in nuclear for example, the International Atomic Energy Agency (IAEA) has time-consuming processes that anyone aspiring to develop nuclear power programmes must follow. This includes verifying site suitability and site characterisation to produce key documents: the Environmental Report (ER) and Preliminary Safety Analysis Report (PSAR). An early GO/NO GO decider, site assessment needs to be as fast, reliable and effective as possible. It takes a highly reactive and resourceful team to do this.

Profound Siting Expertise

Given the diversity of global environments and sites, expertise in a wide range of related disciplines is a key requirement:

  • Seismology
  • Hydrology and Hydrogeology
  • Geology
  • Geotechnics, earthworks and foundations engineering
  • Oceanography
  • Environmental monitoring and impact assessment
  • Demographics

Knowhow in 4 stages

  • Site Survey: Analysis and simple screening of a region to select a candidate site. For NPP, sites fitting the plant’s usually predetermined design must be found.
  • Site Selection: Further screening analysis based on criteria including safety, environment, socio-economics, engineering and costs is used to rank the sites in order of suitability.
  • Site Assessment: Based on detailed soil and subterranean investigations and characterization, the acceptability of the preferred site is established.
  • Pre-operational stage: Formal confirmation of site suitability and preparation and submission of a license application to the regulatory body is carried out – with ongoing monitoring and justification of the site up to operation.

Geotechnical recommendations

Data from a well conducted geological evaluation (everything related to potential hazards in the soil and earth) is useful for the geotechnical analysis of the site. In the right hands this data will lead to solid recommendations; for foundations, design parameters, earthquake engineering and more.


SITE-SEEING FOR THE FIRST NUCLEAR POWER PLANT IN JORDAN

 

  • Nuclear site selection in Jordan. Erna Van Echelpoel with Prof. Dr. Khalil Ibrahim (Hashemite University of Jordan) – photo Tractebel Engineering
  • Nuclear site selection in Jordan-drilling – photo Tractebel Engineering
  • Jordan nuclear site selection-geotechnical investigations – photo Tractebel Engineering

 

Tractebel Engineering, in consortium with Arab Consultants Bureau and Bureau Veritas, is working with the Jordan Atomic Energy Commission (JAEC) on the Site Selection and Characterisation for the Kingdom of Jordan’s first NPP. This is a big deal as, unlike its oil-rich neighbours, Jordan has to import energy to meet its needs. But the country does have good uranium deposits; by developing nuclear Jordan could become energy sufficient – and even export energy.

But major siting challenges exist due to active faulting in the region. Jordan sits close to the border of the Arabic and African tectonic plates known as the Dead Sea Transform Fault, which runs north to south across Aqaba and into the Red Sea; so the site must be at a safe distance from the coast. As Jordan’s short 26 km Red Sea coastline is the most likely source for the cooling water requirements, this poses difficulties. Nevertheless, investigations are ongoing to find a suitable site of a minimum 6 km2 of which every aspect (geology, seismology, geophysics, geotechnics) will be analysed in detail. With so much riding on these studies, having an experienced siting partner is essential for Jordan.


SHAKEN NOT STIRRED – CRYOGENIC TANKS IN TAIWAN

 

  • Mailiao cryogenic tanks (Taiwan)-soil improvement by stone column foundations – photo P. Debauche (Tractebel Engineering)
  • Mailiao cryogenic tanks (Taiwan )- Pierre Debauche on site – photo Tractebel Engineering

 

In 1996, Formosa Plastic Group (FPG) began the construction of a Naphata cracking plant off the coast of Taiwan on a 24km2 man-made peninsular just 2 m above sea level. Between 1996 and 2007 over 14 vertical cryogenic and bullet tanks were constructed.

The region is known for its high seismicity. Based on the complex geological and hydrogeology analysis of the site studies, extensive geotechnical evaluation, involving 120 m deep drillings was conducted. Results across the site confirmed that soil stability was poor, with soil liquefaction a major risk during earthquakes. As a result Tractebel Engineering proposed that all cryogenic tanks be built on stone column foundations; securing the requisite safety levels at reduced cost. This was a world first for 80,000m3 tanks.

In 1999, when 8 vertical tanks were in operation, a major earthquake struck the region. Some damage was caused to the site, but the tanks were unaffected. Ongoing evaluation increased the seismic criteria for subsequent installations, but differential settlement measurements performed on the already commissioned tanks fully confirmed the validity of the design hypothesis and technical proposal.


A SITE IN RECORD TIME FOR LNG TERMINAL IN CAMEROON

 

  • Cameroon site selection for LNG export - Pierre Debauche on the way of Mboro village – photo Tractebel Engineering
  • Cameroon site selection for LNG export - Pierre Debauche on the way of Lolabé village – photo Tractebel Engineering
  • Cameroon site selection for LNG export - example of site characterisation – design Tractebel Engineering

 

On behalf of GDF SUEZ Exploration and Production (Global Gas & LNG) for the Cameroon Societe Nationale des Hydrocarbures (SNH), Tractebel Engineering successfully completed 5 site selection studies (in under 2 years) for an LNG liquefaction and export terminal in 2012.

The 5 sites had been shortlisted based on cost, access, constructability, integration into local industrial development projects, safety and operational factors. Assessing each site, called for:

  • Geological and geotechnical studies to define optimal site layout;
  • Reconnaissance missions involving all related techniques, such as geotechnical drillings and tests and geophysical measurements;
  • Tectonic studies and analysis of natural risks (earthquakes, volcanic eruptions, tsunamis) and potential collapse;
  • Calculations of aquifer drawdown and recharge;
  • Production of a digital elevation model using aerial photographs – used to optimise the rubble/ backfill created on the site, etc.

Despite the varied nature of the disciplines involved, Tractebel Engineering was able to provide all competences required thereby limiting coordination problems and ensuring the studies were completed in record time.

Deep Expertise

Many Tractebel Engineering experts bring insights into the ground beneath our feet; but Alain Van Cotthem, Geovalue and Industrial Sites tops them all. Based on his vast experience in tunnelling, he is recognised as a GDF SUEZ Top Expert in the conceptual design for nuclear waste final disposal facilities; above and below ground.

Alain Van Cotthem

Faultless Logic

No plants should be built on high risk sites. Tractebel Engineering recommends and carries out site investigations for many power plant sites – often going deeper than international codes require.

More information

Eric Waffelaert, Competence Centre Manager – Geo Engineering
Erna Van Echelpoel PhD, Geology Specialist
Pierre Debauche
, Geotechnical Specialist

 

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