1 / 18

EFIT (PB) - Design and Preliminary ULOF(ss) Analysis M. Schikorr, D. Struwe (FzK)

EFIT (PB) - Design and Preliminary ULOF(ss) Analysis M. Schikorr, D. Struwe (FzK) EUROTRANS: DM1 WP1.5 : “Safety” Lyon , 10-11 October 2006. Topics:. Design Criteria for EFIT (Pb) 2. EFIT (Pb) design Data for Transient Analysis 3. Some EFIT (Pb) results to the ULOF transient.

cally-rivera
Télécharger la présentation

EFIT (PB) - Design and Preliminary ULOF(ss) Analysis M. Schikorr, D. Struwe (FzK)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. EFIT (PB) - Design and Preliminary ULOF(ss) Analysis M. Schikorr, D. Struwe (FzK) • EUROTRANS: DM1 WP1.5 : “Safety” • Lyon , 10-11 October 2006 EUROTRANS WP1.5 Safety Meeting : Lyon, Oct 11-12. 2006

  2. Topics: • Design Criteria for EFIT (Pb) 2. EFIT (Pb) design Data for Transient Analysis 3. Some EFIT (Pb) results to the ULOF transient EUROTRANS WP1.5 Safety Meeting : Lyon, Oct 11-12. 2006

  3. 1. Some important thermohydraulic EFIT Design Criteria: 1. Use MgO as fuel matrix for the MA-based fuel • Assure an optimal MA burning rate • Operate the system as a sub-critical system (k_eff ~ 0.95 - 0.97) • Account for the relatively low fuel temperatures allowable T_fuel_max < 1600 °C 5. Also use T91 as clad material (as of now). 6. Design core and primary system in such a manner to allow sufficient natural convection flow rate to survive a ULOF transient for at least 30 minutes without „large number“ of pin failures (via gas blowout) EUROTRANS WP1.5 Safety Meeting : Lyon, Oct 11-12. 2006

  4. EFIT ULOF Design Criteria requires : Assure a sufficiently large natural convection flow rate ( > 25 % nominal flow) under ULOF conditions. This implies : 1. keep pressure drop across the core „low“ (~<0.5 bar) by selecting an appropriate fuel pin / subassembly design 2. minimize pressure losses throughout the primary / DHRS system such that total system pressure loss <~ 0.8 bar 3. assure a height differential between the core midplane and the heat sink midplane of ~ 3.7 m EUROTRANS WP1.5 Safety Meeting : Lyon, Oct 11-12. 2006

  5. Several EFIT design iterations were performed : Option 1 : • Assume a constant fuel matrix (i.e. 50% MgO) and vary the fuel pin / sub-assembly design in the two core zones in order to flatten the power profile. Several variations in pin diameters and sub-assembly sizes were tried but it was difficult to achieve a satisfactory radial power distribution without excessive radial form factors. Option 2: Assume a uniform geometric pin / SA design for the two core zones but vary the fuel matrix composition. ENEA / ANSALDO decided for Option 2 with the following design : EUROTRANS WP1.5 Safety Meeting : Lyon, Oct 11-12. 2006

  6. EFIT (Pb) Design Data used: Inner Core Zone CZ1, Fuel 62.5% MgO EUROTRANS WP1.5 Safety Meeting : Lyon, Oct 11-12. 2006

  7. EFIT (Pb) Design Data used: Outer Core Zone CZ2, Fuel 50% MgO EUROTRANS WP1.5 Safety Meeting : Lyon, Oct 11-12. 2006

  8. EFIT (Pb) Fuel Design: Inner and Outer Core Zones Source : D1.6 Draft Sept.2006 Source : D1.6 Draft Sept.2006 Source : V. Sobolev Sep. 2006 EUROTRANS WP1.5 Safety Meeting : Lyon, Oct 11-12. 2006

  9. EFIT (Pb) Data : Inner Core Zone CZ1 EFIT (Pb) Data : Outer Core Zone CZ2 EUROTRANS WP1.5 Safety Meeting : Lyon, Oct 11-12. 2006

  10. Nominal Conditions Inner Core Zone at BOC : EFIT (Pb) Source : D1.6 Draft Sept.2006 EUROTRANS WP1.5 Safety Meeting : Lyon, Oct 11-12. 2006

  11. Nominal Conditions Outer Core Zone at BOC : EFIT (Pb) Source : D1.6 Draft Sept.2006 EUROTRANS WP1.5 Safety Meeting : Lyon, Oct 11-12. 2006

  12. Nominal Conditions Inner Core Zone at EOL : EFIT (Pb) Note that peak clad temperatures exceed 500 °C requiring „coating“ of the T91 clad material. EUROTRANS WP1.5 Safety Meeting : Lyon, Oct 11-12. 2006

  13. Nominal Conditions Outer Core Zone at EOL : EFIT (Pb) Note that peak clad temperatures exceed 500 °C requiring „coating“ of the T91 clad material. There is not much margin to the temperature limit of coated T91 of ~ 550 °C !! Note: Hot spot analysis still pending EUROTRANS WP1.5 Safety Meeting : Lyon, Oct 11-12. 2006

  14. ULOF (ss) Inner / Outer Core Zone at BOC and EOL : • Natural Convection flow rate of EFIT under ULOFss conditions ~ 43 % !! (much higher than the ~ 25% for XT-ADS) • This leads to lower T91 cladding temperatures ( < 700 °C ) for EFIT (Pb) in comparison to XT-ADS ULOFss temperatures ( 790 – 800 °C ) EUROTRANS WP1.5 Safety Meeting : Lyon, Oct 11-12. 2006

  15. ULOF (ss) Inner / Outer Core Zone at BOC : Pgas =~10 bar Pgas =~10 bar Clad failure not an issue at these clad temps. EUROTRANS WP1.5 Safety Meeting : Lyon, Oct 11-12. 2006

  16. ULOF (ss) Inner / Outer Core Zone at EOL : Pgas = 178 bar tent. Pgas = 178 bar tent. Clad failure not an issue at these clad temps. EUROTRANS WP1.5 Safety Meeting : Lyon, Oct 11-12. 2006

  17. 1.) From the TH point of view the current EFIT(PB) design as proposed by ENEA / ANSALDO is quite viable assuming the cladding is „coated“ as clad temperatures exceed 500 °C under nominal conditions. 2.) The calculations thus far have not assumed a form factor to account for the peak pin within the hottest subassembly (f_peak_pin should be ~ 1.04 instead of 1.0 as has been assumed). This will lead to even higher cladding temperatues of the peak pin, possibly in excess of 550 °C. Conclusions on current EFIT (Pb) TH – design (1/2) : EUROTRANS WP1.5 Safety Meeting : Lyon, Oct 11-12. 2006

  18. 3.) Under ULOF steady state conditions at EOL clad failure times are in excess of 1000 hrs as clad temperatures remain below 700 °C MgO fuel temperatures also remain below 1430 °C ( a limit of ~1500 °C was decided not to be exceeded ) 4.) The design exhibits excellent natural convection characterisitics with w_nat ~ 45 % under ULOF conditions ( low pressure losses < 500 mbar ) 5.) The ULOF transient behavior of the design still needs to be analysed in detail Conclusions on current EFIT (Pb) TH - design (2/2): EUROTRANS WP1.5 Safety Meeting : Lyon, Oct 11-12. 2006

More Related