Q135. What is the type of station battery and what is the capacity?

A.       Station battery contains 55 cells, each cell is dry maintenance free cell, 2.0 V, 250 AH.

Q136. What is the alternative source of power in case of failure of station battery?

A.       There is no alternative source of power in case of failure of station battery.

Q137. Where the protective relays operated by this battery supply?

A.       HT VCB protection relays & closing and tripping coils, LT bus-bar protection relays and main ACB tripping coil, DG-3 control panel relays are operated by 110 VDC.

Q138. Which are the equipments started by the battery? State type, voltage & capacity of the battery.

A.       Equipments started by the battery: DG I & II, Diesel air compressor, Diesel pump for UGWT, Diesel pump for HUT, P & H crane etc.   Type: Lead acid , 12 V, 180 AH.

Q139. What are the necessary conditions to be fulfilled and routine check for satisfactory operation of DG

           set?

A.       Following necessary conditions are to be fulfilled for satisfactory operation of DG sets:

·         Availability of control supply voltage.

·         Cooling water level

·         Normal lub. Oil pressure and level

·         Air compressor pressure

·         Healthy condition of starting battery

·         Normal pre-heater water temperature

·         Status checking for auto/manual/off mode

·         Availability of diesel stock for DG in diesel tank.

Q140. What is the use of CAM in plant?

A.       CAM are used to monitor air activity in certain areas at 80 cps or 8 dac/hr. These monitors are giving alarm.

Q141. What type of motor is used in CAM? What is the capacity of the motor?

A.       Single phase capacitor motor is used capacity: ¼ HP or ½ HP.

Q142. Which supply is provided to air monitors and hand driers?

A.       Mostly the air monitors are in emergency plug points but some monitors like in FHA in normal supply also.

Q143.  What are the cares should be taken to starting air monitor?

A.       EHT voltage setting should be zero while starting the equipment. EHT voltage is supplied to GM tube or scintillating counter. 

Q144. Describe the process followed in PREFRE in brief.

A.    Purpose of reprocessing is to recover and purify plutonium and uranium from fission products associated with irradiated fuel from reactor.

Q145. What are the main steps followed for reprocessing?

a.       Fuel is chopped in pieces.

b.      Dissolution in concentrated nitric acid.

c.       Feed clarification through filter.

d.      Uranium and Pu co-extraction in co-decontamination cycle.

e.       U & Pu purification by solvent extraction separately to get respective final product.

f.       Fission products removal as a waste, concentration & storage in waste tanks.

g.      Diluted waste discharge to sea. High & medium waste is stored/transferred for further treatment.

Q146. How many types of fuel is handled in PREFRE?

A..

a.       CIRUS – Size: 50mm dia x 3.6 meters long, a bunch of 20 fuel rods. CASC – lead shielding. Gross Wt. 26 tonnes.

b.      RAPS- Fuel bundle 1.3 mm dia x 2.5 mets long, 220 bundles. Gross we. 62 tonnes.

c.       MAPS –

Q147.  What is the purpose of MBU?

A.         Mixed Bed Unit is used to de-mineralize the pond water which is circulated through.

Q148.   Describe ventilation pattern in fuel handling are and dissolver cell.

A.       FHA – Supply fans are V2F3/F4, Exhaust is taken by E2F1/F2. Push pull type ventilation is provided to pond. At one side air is supplied and exhausted from other side.

            Dissolver Cell – Suction is given to cell No. 1. Also chopper cell exhaust fan is provided for assured vacuum of 1” in dissolver cell.

Q149. What process is carried out in cells?

A.       In cell fissile products are isolated and removed as a high waste. Uranium and Plutonium partitioning is done.

Q150.  What are the special features of metering pumps and air lift?

A.      Metering pumps have double diaphragm operation and they are having good accuracy for liquid transfer at very low rate also.

            Air Lift – This is useful where very slow rate of liquid transfer is required. In this method spreading        air activity/contamination is prevented. No separated maintenance is required like pumps.

Q151.  How remote sampling is done? How it is made fail safe?

A.      Remote sampling is done by air lift. Also vacuum is created in sampling bottle to receive sample. Overflowed liquid is returned to tank via float chamber.

Q152.  Describe ventilation pattern of cell.

A.        Cell are always taken at negative pressure as exhaust fan takes air from cells.

Q153.  What ventilation pattern is followed in lab.?

A.       Air is always flowing from low active to high active areas. Fume hoods & glove boxes are always kept at low pressure than outside. For glove boxes separate blower is provided for prevention of spreading air activity.

Q154. Describe following systems in brief.

A.      1.  Compressor & Air Distribution System: There are 3 Nos. air compressors installed for our plant. Two are in operation at a time. One is standby. One is loading continuously and other is in loading/unloading condition. Their discharge pressure is 7 Kg/cm².Individual compressors are 630 Cubic feet per minute. By common discharge line, air is supplied to fresh air line and plant process.

         2. Boiler & Steam Distribution System: Our boiler is having working pressure 8.25 Kg/cm² & 6 tones/hr. Fuel is furnace oil. Boiler is horizontal fir tube, multi tabular. Outlet steam temperature is 178^o C. This steam is carried through thermally insulated pipes and provided in various areas for ejections and evaporation.

         3. Ventilation system: Our plant has once through ventilation system, low active area to high active area. Air supply fans V1F1/F2, V2F1/F2, V2F3/F4 are providing air to different areas. From that areas air will be exhausted through exhaust fans. High 120 meters stack is provided for exhausting. High stack prevents re-air circulation of same air in plant and due to height, air si diluted till it comes to ground level.

        4. Air Condition System: Conditioned air is provided in low block entrance hall, control room, 1^st fl. Low block, 2^nd fl. & 3^rd fl. HP room, 3^rd fl cabins. Temperature is maintained 55^o C. AHUs are providing this air. In AHUs heat is exchanged with chilled water. Chilled water exchanging heat with coolant in chiller.  Coolant gas is cooled by condensate water in condenser and condenser water is cooled in cooling tower.

        5. Refrigeration Machines: 3 nos. Refrigeration machines are there with 3 nos. condenser and 3 nos chilled water pumps. Normally at a time one refrigeration machine is working.

        6. Exhaust System: 3 Nos. Exhaust fans are provided for exhaust as follows ( 3 are standby)

·         E2F1/F2     - Crane space and FHA

·         E2F3/F4     - A/G, S/G, All cells

·         E2F5/F6     - 2^nd fl. And 3^rd fl. Labs.

         Supply fans are interlocked with exhaust fans to prevent the pressure in a plant. When exhaust system

         fails, supply fan also fails.

         7. Waste Tank Form: Here 10 nos. tanks are installed for storing liquid waste, 3 nos. tanks are of stainless steel for storing high active liquid waste which is acidic and other M.S. steel tanks are storing high alkaline active waste. WOG fan is provided for controlling air activity which is emergency equipment. Infiltration pumps are removing the water from surrounding of tanks.       

        8. Primary & Secondary PCW System: DM water is used in primary process cooled water circuit for cooling, ejectors and evaporators. This water is cooled by Secondary PCW water circuit. Automatically, water level in Pri. PCW circuit is maintained by DM water tank. Being a closed circuit, chances of spreading activity are also reduced. Secondary PCW water also cools Khosla Compressor, used for after coolers of air circuit.

         9. Emergency Power: Emergency power is supplied by Diesel Generators 1,2,3. Priority I & II loads are fed by Generators in case of power failure. Priority II load is cut when one Generator from I & II if failed.

10. Emergency Water: Two underground tanks are there. Each has capacity of 4.5 lack liters of water. One is always kept 100% for emergency and other tank is for normal use. There are two overhead tanks. One is always kept full as a emergency water. Which has capacity of  80,000 liters. In case of total power failure, diesel water pump is provided for pumping the water.

11. Emergency Air System: In case of failure of Khosla compressor, Parkinson Air Compressor is there which is as a emergency load, runs and feeds air to E2 fans dampers for operation and to some monitors. FAL is fed by emergency diesel air compressor in case of Khosla compressor failure.

Q155. Why plant is divided in LOW BLOCK & HIGH BLOCK?

A.        Plant is divided in Low block & High block to prevent cross contamination.

Q156.  Where the emergency exits located and when they are to be used?

A.        Emergency exits are located at 1^st f. Room No. 121, 2^nd fl. Inactive lab. and 3^rd  fl. Pu lab. They are to be used for exit in case of emergency for evacuation.