ML19351E233

Operation Rept 139 for Jul 1972

ML19351E233
Person / Time
Site:	Yankee Rowe
Issue date:	08/25/1972
From:	YANKEE ATOMIC ELECTRIC CO.
To:
References
NUDOCS 8011260302
Download: ML19351E233 (11)

Text

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YANKEE NUCLEAR POWER STATION OPERATION REPORT NO. 139 For the Month of July 1972 1

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l Submitted by YANKEE ATOMIC ELECTRIC COMPANY 4

Westboro Massachusetts l

August 25, 1972 1

1 30%

8011260

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O This report covers the operation of the Yankee Atomic Electric Company at Rowe, Massachusetts for the month of July,1972.

During the period the plant load varied between 151.2 !Ge and L56.0 ige as the circulating water temperature fluctuated between 61'F and 52 F.

Two scheduled and two unscheduled plant shutdowns occurred luring the report period. The first scheduled plant shutdown occurred on July 1 at 06h8 hours for the purpose of control rod drop time testing.

Following completion of the testing the turbine generator was phased to the line at 1148 hours0.0133 days <br />0.319 hours <br />0.0019 weeks <br />4.36814e-4 months <br /> and the plant was loaded to 498 MWt at 1345 hours0.0156 days <br />0.374 hours <br />0.00222 weeks <br />5.117725e-4 months <br /> that date.

The second scheduled plant shutdown occurred on July 29 at 0726 hours0.0084 days <br />0.202 hours <br />0.0012 weeks <br />2.76243e-4 months <br /> for the purpose of control rod drop time testing.

Following completion of the testing the turbine generator was phased to the line at

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1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> and the plant was loaded to 498 MWt at 1726 hours0.02 days <br />0.479 hours <br />0.00285 weeks <br />6.56743e-4 months <br /> that date.

Leakage had been noted from a crack in the charging line in the vicinity of the thermal sleeve vapor container penetration.

On May 29-30, 1972 a temporary repair was effected consisting of removal of the defective section of charging line and insertion of a coupling. During the July 29 shutdown period survei mee testing was performed on the charging line.

The surveillance consin ced of liq'.ud penetrant examination of the socket weld and the charging line itself for a distance of approximately six 9

inches either side of the coupling. No defects were detected.

The first unscheduled plant shutdown occurred on July 6 at 0026 hours3.009259e-4 days <br />0.00722 hours <br />4.298942e-5 weeks <br />9.893e-6 months <br /> for the purpose of effecting repairs to the generator air break switch.

Following completion of the repairs the turbine generator was phased to the line at 1056 hours0.0122 days <br />0.293 hours <br />0.00175 weeks <br />4.01808e-4 months <br /> and the plant was loaded to h98 IGt at 1230 hours0.0142 days <br />0.342 hours <br />0.00203 weeks <br />4.68015e-4 months <br /> that date.

The second unscheduled plant shutdown was initiated by a reactor scram and subsequent turbine trip on July 17 at 0900 hours0.0104 days <br />0.25 hours <br />0.00149 weeks <br />3.4245e-4 months <br />. Further dis-crasion of this shutdown is presented as Abnormal Occurrence 72-10, this riport.

On July 15 plant load was reduced to 450 ist to permit removing from service a single main coolant loop and location of the source of a high, valve stem leakoff temperature. The No. h loop was removed from service l

first and the valve stem leakoffs for the bypass valves; SC-MOV-553; and SC-MOV-554 were plugged. This repair did not remedy the situation.

No. h loop was returned te service and No.1 loop was removed from service. The stem leakoff for CH-V-61h (bl^ed line manual root isolation valve) was plugged and the temperature returr.ed to normal. The No. 1 loop was returned to service and the plant load was increased to 498 MWt.

The first, Core X vapor container air leckage surveillance period vas terminated on July 17, 1972, and the second such period was commenced l

on July 18, 1972.

Leakage during the entire report period was normal.

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Plant Abnormal Occurrences Abnormal Occurrence No. 72-9, "Lov Nitrogen Overpressure in the l

"sfety Injection Accumulator".

On July 12 at 1900 houre the safety injection accumulator nitrogen l

overpressure, low pressure alarn sounded indicating a decrease from a normal l

h20 psig to h15 psig. The pressure decreased to approximately 400 psig, constituting a violation of the Technical Specifications limit of 410 psig.

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A leak through the pilot regulator diaphragm caused one nitrogen j

supply regulator to fail closed and simultaneously vented the accumulator overpressure to atmosphere. The second supply regulator did not perform its function of maintaining the nitrogen overpressure above 410 psig.

The second supply regulator was adjusted to maintain the over-pressure at h20 psig. The defective pilot regulator diaphragm was replaced and the first supply regulator was returned to service.

Abnormal Occurrence No. 72-10, " Plant Trip".

Oa July 17, 1972 at 0900 hours0.0104 days <br />0.25 hours <br />0.00149 weeks <br />3.4245e-4 months <br /> while operating at h98 MWt a reactor scram and turbine trip occurred.

Prior tc the plant trip the vital bus voltages became unbalanced O

due to a ground vu the primary channel power supply.

When the No. 1 main coolant flov transmitter was disconnected the ground was suddenly removed.

The primary channel power supply was unable to compensate for the sudden load change and the main coolant pressure signal momentarily fell below the reactor trip setting of 1800 psig.

The ground was caused by water dripping from the flow trat;ritter bypass valve into the signal cable junction box.

The water was drained from the box and the cable leads dried. This action removed the ground.

The reactoi was brought critical; the turbine generator was phased te che line at 1231 hours0.0142 days <br />0.342 hours <br />0.00204 weeks <br />4.683955e-4 months <br />; and the plant was loaded to h98 MWt at 1h02 hours that date.

Abnormal Occurrence No. 72-11, " Failure of Control Rod No. 19 to Fall Completely Into the Core".

f On July 29, 1972 during control rod drop time surveillance tests, j

control rod No. 19 failed to fall completely into the core when scrammed from the fully withdrawn position. It dropped from 90 inches to approxi-mately 23 inches constituting a violation of Technical Specifications.

i With che aid of the pulldown coil the control rod vts driven in from 23 to 15 inches; the scram breakers were opened and the control rod fell su -cessfully into the core. Subsequently, the control rod was withdrawn to 90 i ches and when the scram breakers were opened it dropped, completely, into the core.

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O Plant Load Reductions July 15 (0800-1113):

Plant load reduction to 121 MWe to isolate valve stem leakoff lines in main coolant loops No.1 and No. 4.

Plant Shutdowns Shutdown No. 123-10-72:

7/1/72, plant shutdown for control rod drop time testing. Total outage time:

5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />, 0 minutes.

Shutdown No. 12h-10-72:

7/6/72, plant shutdown to effect repairs to the unit airbreak switch. Total outage time: 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />, 30 minutes.

Shutdown No. 125-10-72:

7/17/72, plant trip due to a ground on the primary channel power supply. Total outage time:

3 nours, 31 minutes.

Shutdown No. 126-10-72:

7/29/72, plant shutdown for control rod drop time testing. Total outage time: 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, 3h minutes.

Plant traintenance The following is a list of pertinent plant maintenance items performed by the plant staff during the month of July, 1972.

1.

The No. 1 and No. 3 charging pumps were repacked.

2.

One leaking tube in the No. 2 auxiliary boiler was plugged and seal velded. The bsiler was then returned to standby service.

3.

The relief valve for the No. 3 charging pump was replaced due to a slight leak at the lower flange.

Instrumentation and Control The following is a list of pertinent instrumentation and control maintenance items performed by the plant etaff during the month of July,1972.

1.

A gate house to control room se("rity alarm was installed.

2.

A vater leak detector has been installed in tae radioactive pipe chase.

3.

The pilot regulator diaphrages for the accumulator nitrogen overpressure regtlators were replaced.

Reactor Plant Performance Measurements with the incore instrurhntation were performed under j

the following plant conditions:

7 496 MWt; 512 F Tave; Control Rod Group A @ 79 ", B, C and D @ 87 ";

1h65 ppm boron; equilibrium xenon.

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-u-The results of the measurements were:

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Clad Assembly Assembly F

1 99 1.92 N

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F 1.48 1.38 H

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I Maximum Outlet F 568 567

' Erratum: Operation Report No. 137, page 4, F r

caloy Clad AH Assembly should be corrected to read 2.61.

Secondary Plant Performance Feedwater heater terminal differences were as follows:

1 No. 1 = h.02 F No. 2 = 7 92 F No. 3 = 4.9h F The condenser performance was as follows:

I 154.3 !Ge; 1.73" Hg B.P.;

496.2 rut; 59.5 F C.W. in; TfD = 18.15 F; cleanliness factor = 85.h%.

i Chemictry j

The main coolant boron concentration was reduced frca lh8h ppm j

to lh00 ppm to compensate for normal core depletion.

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The main coolant pH averaged 5 16 during the period.

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The main coolant beta-gamma specific activity and crud level i

averaged 9.24 x 10-2 ue/ml and 0.02 ppm respectively.

1 The main coolant tritium concentration averaged 9.44 x 10 ue/ml

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during the report period.

h The iodine-131 specific activity averaged 1.1h x lo ue/cc and i

the iodine 131/133 atomic ratio averaged 1.82.

i A crud sample for the month collected on July 27 had the following i

radiochemical analyses: dpm/cg crud

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I Cr-51 Mn-54 Fe-59 Co-58 5

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j 1.15 II 3.k1 x 10 7,99 x yg 2.h9 x 10 i

Co-60 As-110M4 4

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6.08 x 10 2.73 x 10 2.73 x 10 1.*3 x 10 l

A main coolant gas sample, collected on July 11, had the following 4

j radiochemical analyses: uc/cc gas 1

l Ne-133 _1 Xe-135 _y Ar-h1

-1 9.07 x 10 1.03 x 10 6.50 x 10 t

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O Health and Safety Four shipments totalling 113 drums of low level vaste containing h8.8 me were made during the period.

Waste disposal liquid releases totalled 53,372 gallons containing 0.05h me of gross beta-gamma activity and 102.88 curies of tritium. Gaseous releases during the period totalled 1.112 curies of gross beta-gamma activity.

l Secondary plant water discharged totalled 303,553 gallons containing 0.018 me of gross beta-gamma activity and 0.16 curies of tritium.

Radiation exposure doses for Yankee plant personnel as measured by film badge, for the month of July,1972 were as follows :

Average accumulated exposure dose:

40 mrem Maximum accumulated exposure dose: 220 mrem 4

Operations Attached is a su= mary of plant operating statistics and a plot of daily average load for the month of July,1972.

Operations Reports No. 137, page 7 and No. 138, page 5, entitled

" Operating Summary", have been changed to show revised values for the Region Average faclear Burnup as determined by new flow correction factors.

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o YANKEE ATOMIC ELECTRIC COMPAI;Y - OPERATING SU'o*ARY July 1972 ELECTRICAL MONTH YEAR TO EATE Gross Generation KWH 109,h63,200 398,812,300 13,h1L,688,200 Sta. Service (While Gen. Incl. Losses)

KWH 7,171,738 26,387,5h5 867,457,159 Net Output KWH 102,291,462 372,42h,755 12,547,231,041 Station Service 6.55 6.62 6.h7 Sta. Service (While Not Gen. Incl. Losses) KWH 166,029 5,327,365 38,431,757 Ave. Gen. For Month (Thk)

KW 147,128.0 Ave. Gen. Running (716.43)

KW 152,789.2 PLANT PERFORMANCE Net Plant Efficiency 5

29.1h 28.85 28.49 Net Plant Heat Rate btu /KWH 11,711 56 11,829 29 11,978.76 Plant Capacity Factor 78.63 42.10 75.17 Reactor Plant Availability 97.82 56.95 83.89 MONTH CORE X TOTAL NUCLEAR Hours Critical HRS 728.70 1,825 93 87,310.92 1

7 68 Times Scra:rmed Buruup Core Average M4D/MrU Th9.82 1,705.00 h

Region Average M4D/MIU A (INNER) 659.3371 1,485.Sh73 841.0473 B (MIDDLE) 822.8780 1,873.6476 843.3176 C (GUTER-ZIRCALOY) 677.h135 1,539.3213

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O YAIIKEE ATOMIC ELECTRIC C0!/PANY - OPERATING

SUMMARY

May 1972 ELECTRICAL MONTH YEAR TO DATE Cross Generation KWH 39,660,900 187,349,000 13,203,224,900 Sta. Service (While Gen. Incl. Losses)

KWH 2,608,181 12,694,365 853,763,979 Net Output KWH 37,052,719 174,654,635 12,3h9,h60,921 Station Service 6.58 6.78 6.47 i

Sta. Service (While Not Gen. Incl. Losses) KWH 2,4h1,60h 4,780,865 37,885,257 Ave. Gen. For Month (Thk)

KW 53,307 7 Ave. Gen. Running (262 53)

KW 151,071.9 g

PLANT PERFORWdCE Net Plant Efficiency 29.60 28.26 28.48 N*t Plant Heat Rate btu /KWH 11,529.56 12,076,26 11,982.97 nant Capreity Factor 28.0h 28.24 75.15 4

React,or Plant Availability h0.46 h0.32 83.68 8

i NUCLEAR MONTH CORE X TOTAL Hou.s Critical HRS 405.85 L05.85 85,890.8h 1

6 67 Tin.es Scrar.med Burnup Co e Average MWD /fGU 267.38 267.38 Region Average MWD /MfU A (INNER) 23h.55h 23h.554 18,590.05h B (MIDDLE) 293.612 293.612 10,203.282 C (OUTER-ZIRCALOY) 241 386 2hl.386 2hl.386

• Corrected burnup for new Flow Correction Factors.

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YANKEE ATOMIC ELECTRIC COMPA'iY - OPERATING SUM. VARY Junu 1972 ELECTRICAL MONTH YEAR _

TO DATE Gross Generation KWH 102,000,100 289,349,100 13,305,225,000 Sta. Service (While Gen. Incl. Losses)

KWH 6,521,h42 19,215,807 860,285,421 Net Output KWH 95,478,658 270,133,293 12,444,939,579 Station Service 6.39 6.64 6.h7 Sta. Service (While Not Gen. Incl. Losses) KWH 380,471 5,161,336 38,265,728 Ave. Gen. For Month (720)

KW 1h1,666.8 Ave. Gen. Running (653.45)

KW 156,094.7 e

PLANT PERFDRMANCE Net Plant Efficiency 5

29.65 28.7h 28.49 Net Plant Heat Rate btu /KWH 11,510.12 11,874.57 11,978.76 Plant Capacity Factor 74.54 35.88 75 1h Reactor Plant Availability 98.93 49 98 83.79 MONTH CORE X TOTAL NUCLEAR Hours Critical URS 691.38 1,097.23 86,582.22 0

6 67 Times Scra:amed Burnup Core Average M4D/ICU 687.88 955.18 h

Region Average M4D/KrU A (INNER) 591.6562 826.2102 19,181.7102 B (MIDDLE) 757.1576 1,050.7696 11,020.4396 C (OUTER-ZIRCALOY) 620 5218 861.9078 861.9078 Corrected burnup for new Flow Correction Factors.

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