ML19351E094
| ML19351E094 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 08/20/1968 |
| From: | YANKEE ATOMIC ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML19351E093 | List: |
| References | |
| NUDOCS 8011250592 | |
| Download: ML19351E094 (8) | |
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YANKEE NUCLEAR PCWER STATION OPERATION REPORT NO. 91 For the month of July 1968 O
Submitted by YANKEE ATOMIC ELT,TRIC COMPAhT Boston Massachusetts
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This report covers the operation of the Yankee Atomic Electric Company plant at Bove, Massachusetts for the month of July,1968.
(s Plantloadvariedbetween172.1IGeand180.fIGeascirculating water inlet temperature fluctuated between 61 F and 48 F.
The monthly control rod exercise was performed on July 15. Control rods No. 17 and No. 21 could be moved in but could not be withdrawn beyond the indicated positions of 86 2/8 and 87.3/8, respectively; other rods behaved normally.
An increase in the frequency of personnel entries into the vapor container has been experienced due to the in-core flux vire modification program. Administrative controls on allowable exposure to airborne tritium has limited work time in the containment. An effort was made to reduce the atmosphere tritium concentration by diluting the entrained vapor. This~vas accomplished by continuously dispersing steam from a 15 psi supply into the_ vapor container; tritiated condensate water was removed to vaste disposal through the vapor container drain tank. Over a period of seven days this process resulted in a reduction of airborne tritium levels from T.1 x'10-5 uc/cc to 0.8 x 10-5 uc/cc.
During_a routine vapor container inspection on July 19, a leak from the No. 1 main c_olant pump. stator cap was detected. A scheduled l
power reduction vas initiated and lead was decreased to 450 MWt.
At 1500 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.7075e-4 months <br /> the No. 1 loop was isolated and loop cooldown commenced. Vapor container access was facilitated by reducing containment pressure approx-L imately one psi. The pressure decrease was effected by purging 55,000 ft3 of container air through the vapor container drain tank to the primary vent stack.
On July 20 at 0121 hours0.0014 days <br />0.0336 hours <br />2.000661e-4 weeks <br />4.60405e-5 months <br /> the plant was taken off the line and No.
1 loop was drained. The pump stator cap was removed and a new gasket was installed. During the outage period, three'in-core flux vire tubes that had been cut to allow insertion of test ion chambers were connected and successfully tested as flux vire paths; sixteen useable paths are now available. Additional work performed included replacement of Nc>. 5 control rod indicating coil stack and cleaning of the tubes in the main condenser.
The plant was phased on the line July 21 at 1126 hours0.013 days <br />0.313 hours <br />0.00186 weeks <br />4.28443e-4 months <br />.
Following plant startup a severe water hammer was experienced in No. 2 feedwater heater; plant operation was continued with the heater isolated from the feedwater cycle. This condition apparently was caused by partial flooding of the heater shell caused by drawing hot drains from the No. 1 heater through a common drain line. On July 22, the No. 2 heater was valved into the system without difficulty.
The International Atomic Energy Agency was notified that it vould be necessary to remove the seals on the reactor head missile shield to effect the replacement of the No. 5 control rod indicating coil stack.
These seals were removed on July 20 by Yankee personnel and retained for the Agency representative.
The third Core VII air charge to the vapor' container was completed; containment leakage during the 33 day period between air charges was computed to be.0.030% per day.
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Control rod groups B, C and D vere moved out.one step to 4
87 6/8 as part of the Core VII rod step wear program.
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Pl^nt load reductions during the period were as follows:
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July 2 -(0108-0308)': Load reduction to lh5 MWe due to i
electrical storm in the area.
July 3 (1145-1520):
Load reduction to 10 MWe for repair of'a leak in the turbine 1st point extraction drain line.
July 10 (0840-1330): ' Load reduction to 15h MWe for repair of a leak in the drain line from No. 1 to No. 2 feedvater heater.
July.17 (1525-1825)i Load reduction tn 1h0 MWe due to l
l electrical storm in the area.
l lt Plant Shutdowns Shutdown-No. 94-7-8 T/20/68 - 7/21/68 scheduled shutdown; plant in j
hot standby; repair leak from No.1 main coolant pump stator cap.
Shutdown duration: 34 hr, 5 min.
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Plant Maintenance The following is a list of pertinent maintenance items performed 1
by the plant staff during the month of July, 1968.
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1.
Two sections of erroded vent piping on the No. 3 feedvater heater j
vere replaced, t
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New lead shielding was installed around the' primary ^ vent stack radiation detector to facilitate access when detector maintenance is necessary.
3.
The mechanical packing on No.1 plunger of No.1 charging pump was replaced.
4.
A drain line leak between No. l' and No. 2 feedvater heaters was repaired by replacing a reducer fitting and section of pipe.
5 A new seal was installed in the lover operating cylinder on the outside door of the vapor container personnel lock.
Instrumentation and Control i
The following is a list of pertinent instrumentation and control maintenance performed by the plant staff during the month of July,1968.
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-1.
Detector tubes and connection sockets were replaced in the primary vent
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stack monitor.
2.
A new main coolant average temperature meter and controls were installed on the main control board, k
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An emergency air supply was installed for the component cooling water trip valve.
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Repairs were made to the main coolant charging flow temperature detector.
Reactor Plant Performance Normal core reactivity depletion of approximately 0.15 2 ppm boron per MWD /MTU was experienced during the period.
The following parameters were determined by means of inct e
instrumentation.
598.7 MW7, 525 F. TAVG' E
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971 ppm baron.
1.8 F
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H Minimum DUBR 3.50
=
581.6 Maximum outlet temperature
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Secondary Plant Performance The condenser performance was as follows:
34.6 T.T.D.
=
55.8 Cleanliness factor
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Feedwater heater terminal differences at 178.5 MWe and 2.65 "HG backpressure were:
No. 1:
11.3 F; No. 2:
10.9 F; No. 3:
5.2 F Health and Safety Waste disposal liquid releases totaling 27,960 gallons contained 0.26 me of gross beta-gamma activity and 65.6 curies of tritium. Gaseous releases during this period were 0.10 me of gross beta-ga==a activity.
Secondary plant water discharged was 280,595 gallons and contained a total of 5.26 me of gross beta-gamma activity and 0.009 curies of tritium.
An additional 0.05 curies of tritium vapor was purged from the vapor container to the primary vent stack during the period.
Average accumulated exposure dose:
67 mren Maximum accumulated exposure dose: 2h5 mren l
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_h-Chemistry The main coolant boron concentration decreased from 1035 ppm to 922 ppa during the period to compensate for normal core burnup. Main coolant pH averaged 5..l'.
Average coolant gross beta-gamma activity and crud level were 9.0 x 10-2 pc/ml aid 0.11 ppm, respectively. The main coolant tritium specificactivityavergge4.h7pc/nlduringthemonth.
Iodine-131 specific
- pc/ml and the iodine 131/133 atomic ratio was 0.81, activity was 2.3 c lo indicating the at sence of any detectable fuel leaks.
A representative crud sample for the month, collected on July 3, had the following radiochemical analyses: dpm/cg crud Cr-51 Mn-Sh Fe-59 6
6 6
2.h2 x 10 1.08 x 10 1.bh x 10 co-58 co-60
^8-llCM4 6
6 3.6L x 10 1.18 x 10 6.70 x 10 A nain coolant gas sample collected on July 8 had the folleving radiochemical analyses:
pc/cc gas Xe-133 Xe-135 Ar-bl
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-2 6.98 x 10-3 1.12 x 10 6.94 x 10 O
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p YANKEE ATOMIC ELECTRIC COMPANY - OPERATING
SUMMARY
JUNE 1968 ELECTRICAL MONTH YFG TO DATE Gross Generation KWH 128,799,000 542,863,800 8,253,748,h00 Sta. Service (While Gen. Incl. Losses)
KWH 7,9ha,871 35,670,711 548,337,644 Net Output KWH 120,850,129 507,193,089 7,705,h10,756 Statton Service 6.17 6.57 6.6h Sta. Service (While Not Gen. Incl. Losses) KWH 0
960,0h1
'5,765,568 Ave. Gen. For Month (720.00)
KW 178,889 Ave. Gen. Running (720.00)
KW 178,889 PLANT PERFORMANCE Net Plant Efficiency 28.21 28.08 28.37 Net Plant Heat Rate btu /KWH 12,098 12,154 12,029 Plant Operating Factor 99 18 68.9h 73.21 Reactor Plant Availability 100.00 78.88 83.09 NUCLEAR MONTH CORE VII TOTAL Hours Critical HRS 720.00 1h73.31 56,580.73 Times Scran:med 0
0 55 Burnup Core Average MWD /MTU 86h.03 1734.45 Region Average MWD /MTU A (INNER) 886.k38 1783 764 19,638.03 B (MIDDLE) 1021.132 2054.026 12,041.45 C (OUTER) 681.562 1362.956 1362 96 D (ZIRCALOY) 890.15h 1790 76h 1790.76 *
- NOTE:
Reported in error as 1790.6h in Operation Report No. 90 L
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YANKEE ATo"IC ELECTRIC COMPANY - OPERATING
SUMMARY
JULY 1968 ELECTRICAL MONTH YEAR TO DATE Gross Generation KWH 123,098,800 665,962,600 8,376,847,200 Sta. Service (While Gen. Incl. Losses)
KWH 7,786,952 h3,457,663 556,12h,596 Net Output KWH 115,311,8h8 622,50h,937 7,820,722,60h Station Service 6.33 6.53 6.6h Sta. Service (While Not Gen. Incl. Losses) KWH 211,190 1,171,231 25,976,758 Ave. Gen. For Month (7hh.00)
KW 165,455 Ave. Gen. Running (709 92)
KW 173,398 PLANT PERFORMANCE Net Plant Efficiency 27.62 27.99 28.36
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Net Plant Heat Rate btu /KWH 12,356 12,193 12,034 Plant Operating Factor 93.53 72.52 73.45 Reactor Plant Availability 100.00 81.95 83.28 NUCLEAR MONTH CORE VII TOTAL Hours Critical HRS Thh.0 2217.31 57,324.73 Times Scrammed 0
0 55 Burnup Core Average MWD /MTU 8h196 2576.bl Region Average MWD /MTU A (INNER) 850.510 263h.274 20,hh8.Sh B (MIDDLE) 986.927 30bo.953 13,028.38 C (OUTER) 676.114 2039.070 2039.07 D (ZIRCALOY) 859.401 2650.165 2650.16
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