PLEX, Plant Uprate and Modernization

PLEX, Plant Uprate and Modernization

Embalse – Conditioning Assessment and Residual Life Studies

Background

The Argentine utility NA-SA, owner and operator of the Embalse CANDU NPP, established a programme for updating and extending the design service life of the plant by 25 years (PLEX project). Ansaldo Nucleare approach to the Embalse PLEX programme is divided in different phases.

Our Solution

The BOP Condition Assessment & Residual Life Evaluation consists in engineering activities governing and addressing the walk-down inspections in the BOP to assure the Customer requirement (25 years PLEX), including a Plant Power Up-rating strategy evaluation for the Thermal Cycle parameters and existing equipment:

  • Evaluation of the as-built configuration of the Thermal Cycle and Essential Systems;
  • Condition Assessment of the thermal cycle (Turbine / Generator, piping, components, electric equipment, instrumentation) carried out by Cognitive Walk-downs in normal plant operation and during planned Outages;
  • In service inspection, Non Destructive Examinations, Tests, Preventive Maintenance actions;
  • Residual Life Evaluation of the thermal cycle in order to extend the Plant Life for 25 years, including Replacement Planning for Components, Items, Spools, Supports;
  • Efficiency Improvement & Power Up-rate study of the Turbine / Generator and thermal cycle by identification and presentation of all possible scenarios, including a preliminary feasibility study

    Ansaldo Nucleare, considered as design authority, has involved the original manufacturers of the main components in order to perform:
  • In site inspection and survey ;
  • Condition assessment of the related components
  • Residual life evaluation

Embalse - Stand—By Diesel Station

Background

The Argentine utility NA-SA, owner and operator of the Embalse CANDU NPP, established a programme for updating and extending the design service life of the plant by 25 years (PLEX project). Ansaldo Nucleare approach to the Embalse PLEX programme is divided in different phases.

Our Solution

In this framework, Ansaldo Nucleare performed specific studies on the ageing conditions of the emergency power system (Stand-by Diesel Generators, SBDG) that finally led NA-SA to proceed with a complete system refurbishment deemed essential to increase availability and safety of the Plant.

The SBDG Replacement Project includes design, supply, installation and on-site tests for the listed below systems:

  • Generator Sets (Diesel engine and electrical generator);
  • Fuel oil transfer, storage, filtering and distribution;
  • Cooling;
  • lubrication oil;
  • Compressed air for the engine start-up;
  • Generator field exciting and voltage regulation;
  • Engine air intake and exhaust;
  • Ventilation and air conditioning;
  • MV switchgears and the related MV protection (microprocessor based);
  • Generator Sets synchronizing equipment
  • MV/LV transformation station and LV distribution boards
  • UPS and Battery banks (see Attachment D);
  • SBDG station control boards (generator set and all ancillaries);
  • Loads sequencing equipment
  • Cables and electrical and mechanical bulk materials

      In more detail the project activities include:
  • Basic & Detail design for the new SBDG station;
  • Supply of four diesel generator sets;
  • Supply of all the auxiliary systems for Diesel Generators operation;
  • Supply of all electrical power and I&C  equipment necessary for normal operating conditions & transient periods;
  • Dismantling of existing equipment;
  • Refurbishment of Diesel Class III Building and of all the external area;
  • Installation of all generator sets/components/equipment;

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Embalse – Chilled Water System Supply

Background

The Argentine utility NA-SA, owner and operator of the Embalse CANDU NPP, established a programme for updating and extending the design service life of the plant by 25 years (PLEX project). Ansaldo Nucleare approach to the Embalse PLEX programme is divided in different phases.

Our Solution

Ansaldo Nucleare is in charge of the design, procurement, supervision to installation and commissioning of the Chilled Water System (CWS) located inside the Turbine Building (TB) of Embalse NPP as well in the Service Building and in the Reactor Containment; in particular:

  • Design to modify and safely upgrade the chilled water system
  • Support to the client for the procurement of four new chillers (2200 kW each machine)
  • Supply of all the other equipment, components and materials for the realisation of the system modification
  • Supervision of constructions/installation activities performed by NA-SA personnel
  • Supervision to commissioning activities performed by NA-SA operators

     The CWS upgrade was planned to cope with the new thermal load related to the Local Air Coolers (LAC) in the Reactor Building (RB) and to overcome the  equipment obsolescence.

    The system produces and delivers the required amount of chilled water for the following:
  1. Air conditioning units serving the Service Building;
  2. Air conditioning units serving the Main Control Room;
  3. Process cooling for D2O Upgrading System and D2O Leakage Detection System;
  4. Generator Excitation System and HVAC equipment inside Turbine Building.

Ansaldo Nucleare activities were:

  • Feasibility study up to the definition of the conceptual design of the new system
  • Basic design
  • Pre-order and post-order (supply follow-up) engineering
  • Procurement of the main components of the system and of the bulk materials
  • Detail design for civil, mechanical, piping, electrical, instrumentation and automation disciplines
  • Engineering for the installation and commissioning activities
  • Supervision to the installation phase
  • Technical assistance for the commissioning phase

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KRSKO - Analysis and Re-Design of RCP MTR CC Connections

The plant is a two-loop PWR designed and built by Westinghouse at the end of the seventies. At the time the construction phase was close to the end, a modification was introduced in the component cooling water circuit that brings water to the Reactor Coolant Pumps motors heat exchangers, lower and upper bearings.  

Scope of the project is to identify an after-the-event justification for considering the current installation acceptable under the licensing point of view, also taking into account that in 1979 older versions of the normative were in place and, possibly, they could grant some less stringent requirements than they accept now. Ansaldo Nucleare will have to provide a professional judging to ascertain whether some caveats could exist that would make the current installation solid under the codes and standards point of view.


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TIANWAN - Unit 1 & 2: Refurbishment of Control Systems for FHM

Scope of the project is an updating of the Fuel Handling Machine Control System (FHMCS), designed and supplied by Ansaldo Nucleare in 2005. The FHMCS was designed for providing required refueling operations with Fuel handling Machine MPS-V-428M type, at Tianwan NPP, Units 1 and 2 (People's Republic of China), with high operational safety during fuel movements in compliance with norms and regulations, acting at Nuclear Power Plants.

The FHMCS consisted in upper and lower level computer control system (CCS) including human-machine interface (HMI), actuating control system (ACS), remote I/O, manual emergency console (MEC) and voice system. It was designed for movement of FHM mechanisms and continuous monitoring of refueling parameters. The updating consists is a replacement of old servers with more powerful and based on up to date technology, their relocation from the Operator Console to inside of additional cabinets, also containing the overload protection, which has been added as part of the current project scope.

The ANN's scope includes the design of the additional cabinets, including their qualification against the applicable seismic requirements, its purchasing, Factory Acceptance Tests and delivery to Volgodonsk, where they will be connected to the Fuel handling Machine for final tests before delivery to the site.


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Embalse Power Uprate Thermal Cycle Optimization and Turbine Replacement

Background

The Argentine utility NA-SA, owner and operator of the Embalse CANDU NPP, established a programme for updating and extending the design service life of the plant by 25 years (PLEX project). Ansaldo Nucleare approach to the Embalse PLEX programme is divided in different phases.

Our Solution

In the frame of the 30-years life-extension project of Embalse NPP, new reactor core and new steam generators are installed, with a nuclear power up-rate from 2015 MWth up to 2064 MWth (+49 MWth). This project entails the complete reconfiguration of the thermal cycle so as to cope with the new nuclear power parameters while enhancing at the same time the BOP efficiency which eventually results in an overall power output increase. The plant life extension & up-rate project also includes an optimization of the feedwater system such that the whole nuclear plant safety margins are increased.

The plant life evaluation and condition assessment – which focused on the turbine, generator and thermal cycle systems – in combination with a feasibility study, identified the set of modifications necessary to achieve the power output increase.

Herewith after are the activities within Ansaldo Nucleare's contract scope:

  • Refurbishment and power up rate of the Turbo / Generator Group: the NPP gross power output is increased of 35.3 MWe. The TG group will be completely refurbished and adapted to the up-rated Thermal Cycle conditions;
  • Modifications to the Thermal Cycle: installation of two high pressure feedwater heater circuits (including two additional high pressure heaters, two forward pumps, the related control valves and piping) and associated changes to the Feedwater System configuration;
  • Feedwater System: improvements include both the feedwater circuit feeding the boilers, with replacement of feedwater isolation, check and recirculation valves, the condensate extraction, with rerouting of reheater drains, as well as  the replacement of an auxiliary feedwater pump and the circuit check and recirculation valves. Changes affecting the auxiliary feedwater circuit – safety related systems because involving the plant heat sink – are fundamentally targeting the reliability enhancement of the entire subsystem. Main feedwater circuit improvements have also the objective of improving plant operability and availability, thus increasing overall plant productivity;
  • Feedwater System refurbishment of the main components of the Feedwater system (e.g pumps and valves) which were affected by aging and obsolescence, with the overhauling of the three main feedwater pumps.

Main activities include:

  1. Basic design engineering (at Home Offices in Italy);
  2. Pre-order and post-order engineering activities on the components and equipment to be replaced/installed;
  3. Detailed design engineering (through involvement of a local engineering company under full responsibility of Ansaldo);
  4. Supply of the main equipment and components, such as turbine rotors, pumps, valves, electric panels, instrumentation, etc.
  5. Management and follow-up of the Suppliers' activities;
  6. Supervision and responsibility of Installation activities;
  7. Support to commissioning activities;
  8. As-Built program.