seismic isolation of nuclear installations in france sollogoub.pdf · 2014. 11. 28. · seismic...

Pierre Sollogoub

Consultant

Member of SILER EAC

France

1

Seismic Isolation of Nuclear Installations in

France

SILER WS

Roma 23-24 September 2014

Introduction

SILER WS Roma 23-24 September 2014 2

Objective:

Present applications of Seismic Isolation of Nuclear

Installations in France

Some specific questions related to seismic isolation

French Base Isolated Nuclear

Installations

CRUAS 900MWe NPP (EDF)

KOEBERG 900MWe NPP (RSA)

La Hague storage pools (COGEMA)

STAR Laboratory in CADARACHE (CEA)

Vessels supports: Phénix, UNGG…

Georges Besse II enrichment plant

3 SILER WS Roma 23-24 September 2014

CRUAS NPP Facility: Nuclear Power Plant – 4 Units (900MWe) EDF (1980)

Location: CRUAS in the Rhone valley

The plant is part of a standardised set designed to 0.2g; presence of a shallow focus 0.3g earthquake

Two twin units Nuclear Island (raft dimensions: 140m x 80m) 300000tons on 2000 pads

Pads: laminated rubber bearings ; 0.5m x 0.5m x 0.065m (3 neoprene layers 13.5mm thick)

Neoprene Rubber

Isolation frequency: 1Hz (the objective was to limit the acceleration to 0.2g, with 5% damping)

Possibility of pads replacement (qualified in-situ procedure)

Koeberg NPP (South-Africa), same type of bearings with sliding plate


Cruas – Seismic input


0.01

0.1

1

0.1 1 10 100

Accele

rati

on

(g

)

Frequency (Hz)

SDD EDF 0.2g

SDD CRUAS 0.3g

CRUAS - Position of pedestals


CRUAS NPP


Cruas NPP

Cruas NPP

Courtesy EDF


KOEBERG NPP


Construction Lower raft and pedestals (31-12-1977) Photo: Spie Batignolles

Koeberg (RSA) NPP

PGA: 0.3 g

Frequency: 0.75 Hz

Pad size: 700x700x130 mm

G modulus: 1.4 Mpa

Friction coefficient: 0.2


La Hague Spent Fuel Storage Pools

Facility: Spent Fuel Storage Pools (1980-85)

Location: La Hague reprocessing plant (near Channel coast)

Objective: withstand seismic and thermal effects

U shaped set of 3 pools. Overall dimensions: about 90m x

83m about 100000 tons on 182 pairs of pads

Pads: laminated rubber bearings 07m x 0.7m x 0.14m (10

neoprene layers 10mm thick)

Isolation frequency : 0.85Hz


La Hague Spent Fuel Storage Pools

La Hague


Typical transversal cross section of a pool Two isolators on a concrete linear support and a

sample bearing in the middle

Courtesy of AREVA

JHR General Design


RJH Seismic Design

Use of industrially proven solution : square elastomere pads

Low damping

Frequency : 0,65 Hz at the end of life

Dimensions of pads : 0,9 x 0,9 m2

Design compressive stress 7,5 MPa

Maximum design distorsion : 1,4

211 Pads

- Review of existing standards: EC8, AFPS90, SETRA Guidelines…

Ageing is taken into account by considering a margin in Shear Modulus

Integration of inspection constraints

- Accessibility

- Testing

Integration of pads replacement capability

Equipment design: margins


CEA – Cadarache RJH Visit of ISSC/IAEA WA2 meeting May 2013



ITER International Thermonuclear Experimental Reactor

Under construction

PGA: 0.32 g

Frequency: 0.55 Hz

Pad size: 900x900x181 mm

G modulus: 1.1 Mpa

Same isolators than RJH

RJH ITER


ITER JHR

Elastomeric bearing

characteristics

900x900x181 mm square bearing

6 layers of 20mm of elastomer

5x 5 mm-thick steel plates + 2 external 15 mm-thick steel plates

Mechanical properties Dynamic shear modulus: Gd = 1.1 MPa

Damping : 5%

Shape factor S 11.25

PGA (hard soil)

Number of isolators 493 195

Mass (t) ~ 300 000 ~110 000

Isolation frequency (Hz) 0.55 0.6

Service loading (NSd) 6.4 MN (s = 8 MPa) 5.67 MN (σ = 7 MPa)

Displacement dbd (mm) 112 108


Precise and careful alignment for Seismic Pad #100

Early November, workers completed the installation of

seismic pad number 100.

November 2011

http://www.iter.org/construction/TKMFoundations http://www.iter.org/construction/TKMFoundations http://www.iter.org/construction/TKMFoundations

http://www.iter.org/construction/TKMFoundations







The 1.8 metre column plus pad

Between the bottom slab (which the seismic pads rest on) and the upper slab there will be

a gap of two metres. All of the formwork supporting the second slab will have to be

removed through this gap. Photo: F4E

February 2013



ITER – Concrete pouring of the slab


Concrete pouring for the B2 slab got off to a start in

December 2013. It will take nine months to pour the

fifteen segments of the basemat.


http://www.iter.org/img/resize-900-90/www/content/com/Lists/WebsiteText/Attachments/137/dsc03909_small.jpg



The completed slab

The B2 slab—14,000 m³ of concrete, 3,600 tons of reinforcement and 2,500

embedded plates—stands ready to receive the first walls of the Tokamak

Complex.

September 2014




Georges Besse II enrichment plant


Seismic spectrum of TRICASTIN

0,0010

0,0100

0,1000

1,0000

0,10 1,00 10,00 100,00

Frequency (hz)

Acc

ele

rati

on

(g

)

SMS 5%

IPS2 5%

GBII

Elastomeric bearing

characteristics

Circular bearing of diameter 500mm

Height around 400mm

Mechanical properties Dynamic shear modulus: Gd = 0.7 MPa,

Damping : 7 %

PGA

Displacement dbd (mm) 100

Some specific questions related to seismic

isolation (1/2)


Modal Analysis for Isolated SSC

Ductility demand

Modal Analysis for Isolated SSCs


The input signal « filtered » by the isolation system is almost sinusoidal, at the frequency of the Isolated Structure (this is formally true only for linear isolators; for non-linear one, this global result still holds)

In that case, the response of all modes at frequencies higher than some few Hz are all in phase

The cumulation of modes in case of analysis of multi-modal system (e.g. piping) must be algebraic and not SRSS:

This is equivalent to a Static Analysis

CQC can be applied with modified coefficients

If the second peak is important, a specific cumulation should be derived.

Floor Response Spectrum


Example: ITER

(fusion experimental

reactor) [Combesure et al, 2010]

Characteristics of the floor signal

Implications for ductility demand

28

Conventional building

o Frequency content in the medium range

Base Isolated

o Low frequency signal, almost sinusoïdal

Ductility demand

o Conventional building There is a possible ductility demand up to a frequency of 15-20Hz: more a

displacement driven load ( sometimes called « Secondary » load)

o Base isolated building The ductility demand is possible only up to few Hz

Almost all SSCs cannot take profit of ductility; over strenght

Seismic Loading is to be considered essentially as force driven loading (« Primary » load)

SILER WS Roma 23-24 September 2014

Inelastic Spectra – RG1.60 spectrum

Frequency


Elastic

Duct. 2.0

Duct. 3.0

Duct. 5.0

Elastic

Frequency [Hz]

333231302928272625242322212019181716151413121110987654321

Response A

ccele

ratio

n [g]

3,4

3,2

3

2,8

2,6

2,4

2,2

2

1,8

1,6

1,4

1,2

1

0,8

0,6

0,4

0,2

0

Base Isolated Structure inelatic FRS

Frequency


Elastic

Duct. 2.0

Duct. 3.0

Duct. 5.0

Elastic

Frequency [Hz]

5048464442403836343230282624222018161412108642

Response A

ccele

ratio

n [g]

6

5,5

5

4,5

4

3,5

3

2,5

2

1,5

1

0,5

0

Equipment behaviour


10-1

100

101

102

100

101

102

fréquence (Hz)

spectre pseudo-accélération m/s2

RCC-E

SQUG

BI structure

Some specific questions related to seismic

isolation (2/2)


Design of Isolators – Material - Qualification

Construction tolerances

Control of vertical loads on isolators Construction phasing

Vertical stiffness of isolators

Soft soil

Tension loads

Ultimate behaviour of the isolation system Margins Beyond design conditions PRA Hard stop

Connecting structures – umbilicals

Vertical solation

Conclusions

French practice has been presented Good behaviour during earthquake Manufacturing quality Nuclear documents: JEAG 4614’2013 USNRC draft NUREG IAEA TECDOC SILER activities

Seismic isolation is a mature technique

Thank you for your attention


seismic isolation of nuclear installations in france sollogoub.pdf · 2014. 11. 28. · seismic...

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