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NOK Nuclear Division IAEA Symposium PLIM, Shanghai

Plant Life ManagementStrategy for long term operation of the Beznau NPP Unit 1 and 2 (KKB)IAEA-CN-155-006

2nd International Symposium on Nuclear Power Plant Life ManagementOctober 15 – 18, 2007; Shanghai, China

Herbert Rust, Head Mechanical Department☏ +41-56-266.75.28� [email protected]

NOK Nuclear Division IAEA Symposium PLIM, ShanghaiSlide 2 October 15 – 18, 2007

Contents

1. Introduction2. Requirements / Remits3. Technical evaluation for an extended operation period4. Nuclear fuel: acquisition / disposal5. Elusive risks6. Plant staff and materials management7. Electricity market / external influencing factors8. Economics9. Conclusions


Contents



1. Introduction


Population (2006): ca. 7.5 Mio.

Area: 41'290 km2Capital: Bern

1. Introduction


KKG

KKB1+2

KKMKKM 355 MW

KKG 970 MWKKL 1165 MW

KKB 365 + 365 MW

KKL

CH-NPP Location1. Introduction


Matterhorn 4478müM

1. Introduction


Beznau Unit 1 Beznau Unit 2Intermediate rad. Waste storage

River Aare

Channel to hydro power plant

NPP Beznau

1. Introduction


1964 NOK decide to build a NPP instead of an oil fired power plant1969 Commissioning of Beznau Unit 11972 Commissioning of Beznau Unit 2

Type: Two Loop PWR Thermal Power: 1130 MWthElectrical Power: 380 MWel (2 Turbines per Unit)

Manufacturer NSSS: Westinghouse ElectricManufacturer Balance of plant: BBC (ABB; ALSTOM)

Historic and Technical data1. Introduction


Cross section of NPP Beznau1. Introduction


1. Introduction• The plant life management was "born" in 1992, when it was

for the first time spoken about ageing management and plant life extension.

• The ageing management is engaged in monitoring the ageing of components, systems and structures; it contains all essential actions of evaluation and control of the ageing concerning the material and the conceptual ageing.

• The expression plant life extension has its origin in the USA because these plants possess a license over an operating time of limited 40 years. (48 NPP's LR for 60 Years / 8 NPP's LRA under Review of 104 US-Reactors).


Contents



2. Requirements / Remits

• Requirements– The report "Perspectives of an extended operating period of the Beznau

NPP (KKB)" of July 2000 was discussed in the NOK management. It can be extracted from the minutes:The management takes affirm notice of the report. In principle it agrees with the plant life management aligned for 50 years of operation as well as with the related investment planning.

– The numbers and facts mentioned in the report are based on evaluations from 1997 until 1999 and are part of the mid-periodic planning.

• Remits– The updating of the facts, figures and declarations, in the beginning set for

only 50 years, was extended to 60 years of operation.


Contents



3. Technical evaluation of an extended operating period

• Initial position / status– The Beznau NPP (KKB) has been operated constantly with base load for

the past 37 years.– The design basis for transients were obviously based on extremely

conservative assumptions.– Using selective measures, such as backfitting, the safety of the plant has

been continuously enhanced.– Thanks to aimed modernisations and careful maintenance, the substance of

the plant is in excellent condition.


3. Technical evaluation of an extended operating periodPotential of KKB after 37 years of operation

0

20

40

60

80

100

Heat up Cool down R-Trip > 10% Pn Load ramp up

Load rampdown

UF PressurizerNozzle

UF ChargingNozzle

UF RHR Nozzle

Nature and position of Transients

Plant

Life R

eserv

e [%]


3. Technical evaluation of an extended operating periodComparison design / actual after 37 years of operation

Heat up 200 55°C/h 81 25°C/hCool down 200 55°C/h 80 25°C/hR-Trip > 10% Pn 220 32Load ramp up 14000 5%NL/Min 1000 1.5%NL/MinLoad ramp down 14000 5%NL/Min 1000 1.5%NL/MinUF Pressurizer Nozzle 1 0.47UF Charging Nozzle 1 0.21UF RHR Nozzle 1 0.25

Design Actual


3. Technical evaluation of an extended operating periodWhat was backfitted in KKB?

0

100

200

300

400

500

600

B u nk e r

s ys t e

mS G

R ep l a

c e me n t

U ni t 2

S G R e

p l ac e m

e n t U n

i t 1P r o

j e ct A N

I SP r o

j e ct Z W

I B EZ

P r oj e c

t P RE S S

U RE

R e pl a c

e me n t

H P- T u

r b i ne

R e ne w a

l C on d .

/ P re h e

a t er

P r oj e c

t ME R

K UR

P r oj e c

t E RG E

SP r o

j e ct R E

Q UA

P r oj e c

t S ID R

E NT

Projects

Mio

. CHF

0

200

400

600

800

1'000

1'200

Mio

. CHF


3. Technical evaluation of an extended operating periodWhat was the evolution of the safety?

Beznau PSA HistoryResults of Full-Scope Level 1 PSA incl. External Events (Seismic, Fire, etc.)

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006

Year

Core

Dama

ge Fr

eque

ncy [

per y

ear]

1986 - 1988: Seismic upgrades

1988 - 1990: 3rd DC-Bus

1990: EPO improvements

1991 - 1993: Emergency bunker system

1994 - 1996: 2nd Hydro-Supply1998 - 2000: 3rd Aux. Feed system

Target CDF value: IAEA, USNRC

Target CDF value: IAEA for future plants


3. Technical evaluation of an extended operating periodCivil structures

• The actions controlling the ageing mechanism of the structures has been established in line with the ageing management program (AMP).

• The procedure for implementing the actions has been defined in line with the AMP and are currently executed.

• The actions related to the "conceptual ageing"1 have been established for dominant scenarios.

• The technical feasibility for the essential actions for an operating period up to 60 years is given.

– 1 "Conceptual ageing" means the gap from the progress of the state of the art (deficiency compared with new or updated codes and rules.)


3. Technical evaluation of an extended operating periodElectrical area

• The systematic registration of the actions to control the ageing of components and systems occurs in line with the AMP.

• The main problem is not the material related ageing but the availability of products and manufacturers and the conceptual ageing due to obsolescence.

• Backfitting and/or modernisation of complex systems are permanent tasks.

• The technical feasibility for the essential actions for an operating period up to 60 years is given.


3. Technical evaluation of an extended operating periodElectrical areaRealisat io n st rat eg y o f t h e elect rical d ep art m en t

KOAL A:Co n cep t o f a req u i re-m en t free co n tro l system u p to 2004T arg et : Un lim it ed o p erat in g licen se

P L E X :P l an t L i fe E xten si o n

T arg et : In vest m en t st rat eg y o p t im ised f o r p lan t lif e ext en sio n in t h e elect rical area

BE DAM :P l an t L i fe M an ag em en t

T arg et : S h o w in g t h at an eco n o m ical o p erat in g p erio d u p t o 50/60 years is g iven


3. Technical evaluation of an extended operating periodMechanical area

• Primary systems– The AMP attests generally good conditions for the major components and

systems.– Exceptions are some materials (Alloy 600) used on penetrations at the

reactor vessel head in Unit 1.– Selective replacement of several components is going to be necessary.– Maintenance activities require more resources especially for the qualified

test methods requested by the authorities.– The containment steel pressure vessel in Unit 1, which is affected by

corrosion, demands selective actions to stop the progress of the corrosion.– The technical feasibility of the essential actions for an operating period up

to 60 years is given.


3. Technical evaluation of an extended operating periodRPV, critical components

Penetrations

InternalsRPV Shell


3. Technical evaluation of an extended operating periodRPV

Cold Leg Flow

RV Head Penetrations

Cold Leg Flow


Cold Leg Flow


RV - Head Penetrations

Inconel 600

Inconel 82/182

Carbon Steel


3. Technical evaluation of an extended operating periodRPV Internals

Split Pins

Number of Split Pins: 58


3. Technical evaluation of an extended operating periodRPV Internals

Baffle Bolts

Number of BaffleBolts: 624Number of EdgeBolts: 540


3. Technical evaluation of an extended operating periodRPV Embrittlement

Plant HeatupRCS Pressure in Function of Effective Full Power Years

0

20

40

60

80

100

120

140

160

180

40 50 60 70 80 90 100 110 120 130 140RPV Temperature [°C]

RCS P

ressu

re [M

Pa]

Allowable Pressure 33 °C/hr, barg) 45 EFPYAllowable Pressure 33 °C/hr, barg) 54 EFPY


3. Technical evaluation of an extended operating periodContainment-Steel pressure vesse

Corrosion Area


3. Technical evaluation of an extended operating periodContainment-Steel pressure vessel

Stress Intensity (SINT) vs. Operating Time

0

50

100

150

200

250

300

350

400

450

500

10 20 30 40 50 60Operating Time [Years]

SINT

[MPa

]

0

5

10

15

20

25

30

35

40

45

50

Wall T

hickn

ess [

mm]

SINT effective SINT allowed Wall Thickness


3. Technical evaluation of an extended operating periodMechanical areasBEDAM, distinctiv mechanical actions


3. Technical evaluation of an extended operating periodMechanical area

• Balance of plant– HP-turbines: total replacement in the years 1993 until 1995, problems are not expected up to 60 years of operation.– LP-turbines: end blades replaced, maybe replacement of the blade carriers needed. – Condensers: total replacement (titanium tubes) in the years 1993 until 1998, problems are not expected for an operating period up to 60 years.– Pre-heater system: total replacement or retubing in the past years, problems are not expected for an operating period up to 60 years.– Moisture separator/re-heater: device in Unit 1 replaced, total replacement in

Unit 2 is planned for 2007, therefore, 60 years of operation can be achieved without any problems.– Replacement of the entire turbine controls (project "MERKUR") just finished.


3. Technical evaluation of an extended operating periodPotential of KKB after 37 years of operation

0

10

20

30

40

50

60

70

80

90

100

HP-Turbine LP-Turbine LP-Blading Stop valve casing Bypass valve casing Steam-Line (HP-Turbine)

Plant

Life

reserv

e [%]

> total replacement 1995


Contents



4. Nuclear fuel: acquisition / disposal

• Acquisition– Current contracts cover the needs until 2010.– Fabrication occurs with RPU or with enriched uranium after 2010. Costs are

well known based on long term contracts until 2020.– No MOX-application after 2011, optimisation of enrichment and burn-up

reduces the number of new fuel-elements (FE) per cycle.• Disposal

– After mid 2006 it is not allowed to reprocess FE for 10 years by law.– Spent FE are first to be stored in the pools and later stocked in ZWIBEZ-

storage containers after 2008.


Contents



5. Elusive risks• Hydro power plant Beznau (part of the emergency supply of the KKB)

– Concession is given until 2022.– For an operating period of 60 years, the emergency power supply of the

KKB possibly results from diesel generators.• New earthquake analysis for CH-NPPs

– The Swiss Federal Nuclear Safety Inspectorate (HSK) as well as swissnuclear see lacks in the study.– Retrofits, besides a current project, appear as necessary.

• Environment in the sector of nuclear energy– New NPPs in Finland and France, phasing out of nuclear energy in

Germany. – Youngest discussions about environment and CO2.– In the USA license renewal for 60 years of operation is common practice.


Contents



6. Plant staff and materials management• Staff

– Workforce (estate of 01.07.2007: 490 people) with slightly increasing tendencies. Reasons are:

– Longer overlapping times concerning retirements of operating staff.– Age of the equipment demands increasing maintenance activities as well as

required testing qualifications for ISI.• Materials management

– The need of operating materials will not change compared with today.– The need of spare parts depends on the maintenance strategy and will be

additionally complicated as a result of exclusion of manufacturers from the market and obsolescence.

– The inventory of spare parts has be to reduced systematically before the shutdown of KKB.


Contents



7. Electricity market / External influencing factors• Electricity market

– Estimations are based on an Axpo-study (P2020) allowing the following statements concerning the KKB:

– Replacement need from today's point of view is given in any case.– Nuclear energy is a possible option in the mid- and long-term range because it is

free of CO2 emission.– Nuclear energy features cost advantages (increasing gas and CO2 prices).

• External influencing factors– KEG and KEV (New nuclear energy law and regulations)

– Regulations are based on unlimited operating period (time) for CH-NPPs.– Additional requirements in connection with periodic safety reviews are to be

expected.– The Swiss Federal Nuclear Safety Inspectorate (HSK) did not sign any general

provisos for an operating period of more than 40 years.


Contents



8. EconomicsInvestments, 50 years of operating

02005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

kCHF

pessimisticrealisticoptimistic


8. EconomicsInvestments, 60 years of operating

02005 2007 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029

kCHF

pessimisticrealisticoptimistic


8. Influence of outage durations

0

10

20

30

40

50

60

70

80

6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30Year

Days

normal RA normal RV + RA addition for 50/60 years


8. EconomicsFull production costs, 50 years of operation

02005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

Costs

of pr

oduc

tion (

kCHF

)

Rp./k

Wh

Full cost kCHF pessimistic Full cost kCHF realistic Full cost kCHF optimisticRp./kWh pessimistic Rp./kWh realistic Rp./kWh optimistic


8. EconomicsFull production costs, 60 years of operation

02005 2007 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029

Costs

of pr

oduc

tion (

kCHF

)

Rp./k

Wh

Full cost kCHF pessimistic Full cost kCHF realistic Full cost kCHF optimisticRp./kWh pessimistic Rp./kWh realistic Rp./kWh optimistic

.


8. EconomicsComparison of production costs / market prices

2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030

Operating Time [Y]

CHF [

Rp/kW

h]

60 Y 50 Y



2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030

Operating Time [Y]

[Rp/k

Wh]

Best Case Worst Case



2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030

Operating Time [Y]

[Rp/k

Wh]

60 Y 50 Y Best Case Worst Case


Contents



9. Conclusion• The Beznau NPP (KKB) was operated gently for basic load only for

the past 37 years. The number and magnitude of transients show only "half-time".

• The safety status of the KKB can be compared with new plants because of extensive back- and retrofitting.

• Thanks to selective modernisations and diligent maintenance, thecondition of the KKB is excellent.

• If the identified actions can be realised, an operating period up to 60 years is technically as well as economically possible.

• Some uncertainties are located in the areas of the "conceptual aging", the "future of the hydro power plant" as well as the "earthquakeissue".


Thank you for your attention !

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