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IRS /FzK W.M.SchikorrEUROTRANS DM1 Safety Bruxells, 17 March 2006 1

Transients to be Analysed for theTransients to be Analysed for the LBE–cooled XT-ADS and LBE–cooled XT-ADS and Lb–cooled EFIT designsLb–cooled EFIT designs

M. Schikorr (FzK) M. Schikorr (FzK)

EUROTRANS-DM1-Safety Meeting

Bruxells, 17 March 2006

Forschungszentrum KarlsruheTechnik und Umwelt

IRS /FzK W.M.SchikorrEUROTRANS DM1 Safety Bruxells, 17 March 2006 2

Topics of this discussion:

1. Types of Typical Plant Transient Initiators to be analyzed for the LBE / Lb – cooled ADS designs

2. Summary of Results of the Transient Analyses of the 80 MW LBE – cooled XADS (ANSALDO Design)

3. List of Transients that were analyzed for the PDS-XADS

4. List of Transients to be analysed for XT-ADS and EFIT

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IRS /FzK W.M.SchikorrEUROTRANS DM1 Safety Bruxells, 17 March 2006 3

1. Typical Plant Transient Initiators for :

- Protected case (with normal shutdown) and

- Unprotected case (shutdown failure).

1. Loss of Flow (LOF) : pump failure

2. Loss of Heat Sink (LOH) : heat sink failure

3. Overpower Transient (TOP) : reactivity insertion

4. Loss of Coolant (LOCA) : primary system leak

5. Design specific transients : i.e. HX tube rupture, jet

etc.

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2. Summary of XADS Safety Transient Analyses :

1. For the LBE-cooled 80 MWth XADS, as designed by ANSALDO, no transient could be identified that could lead to severe or catastrophic

consequences.

2. For the worst combination of transients (ULOH+ULOF) the „grace“ time until excessive clad temperatures (> 1000 °C) are reached is between

30 and 60 minutes.

3. The dynamic response of the system is in general very benign to all transients considered, mainly due to it‘s :

a. large heat sink / heat buffer capacitiy provided by the LBE coolant, and

b. excellent natural convection characterisitics of the core/plant design (that is specfic to

the Ansaldo XADS design !!!!)

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3a. List of Transients that were analyzed for the LBE-cooled

80 MW PDS-XADS (Ansaldo-Design)

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3b. List of Transients that were analyzed for the LBE-cooled

50 MW Myhrra (SCK-CEN Design)

Source : D66 PDS-XADS

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1. Input of maximum reactivity margin (TOP WS)

2. Loss of forced lead circulation (LOF WS)

3. Loss of secondary heat sink (LOHS WS)

4. Overcooling of the primary circuit (OVC WS)

5. Steam header break with MCPs in operation

6. Coincidence of initiating events

Initiating events of ultimate accidents without scram (WS):

3c. List of Transients that were analyzed for the

Lb-cooled BREST Reactor Design

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3d. Preliminary List of Transients to be analyzed for the

LBE- cooled XT-ADS Design.

Preliminary List is currently defined as :

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3e. Preliminary List of Transients to be analyzed for the

Lb-cooled EFIT Design.

Preliminary List is currently defined as !