ML19351E351

Operation Rept 100 for Apr 1969

ML19351E351
Person / Time
Site:	Yankee Rowe
Issue date:	05/23/1969
From:	YANKEE ATOMIC ELECTRIC CO.
To:
Shared Package
ML19351E350	List: ML19351E349 ML19351E351
References
NUDOCS 8011280154
Download: ML19351E351 (9)

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YANKEE NUCLEAR F0WER STATION t

OPERATION REPORT NO. 100 Regulatery Filo Cy.

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April 1969 7-r,-y

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YANKEE ATOMIC ELECTRIC COMPANY Boston Massachusetts l

l May 23, 1969 i

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This report covers the operation of the Yankee Atcmic Electric Ccapany plant at Rowe, Massachusetts for the month of April, 1969 1

l Flant load at the start of the peciod was 179 ige; plant stretch.ut operaticr. r esulted in a load decreuse to 162 ige at the end of the perio/.

On April ll, vapor container air particulate and routine tritium measurements indicated an increase in containment atmosphere activity concentration. At 1k11 hours, the plant was shutdown and placed in hot l

standby condition to allow an unlimited inspection of primary system cceponents.

j I

Pinhole type leakage was detected f.om the plug adapter and the seal cap of the north inecre inetrumentation thimble. At 1611 hours0.0186 days <br />0.448 hours <br />0.00266 weeks <br />6.129855e-4 months <br /> a primary system cooldevn was initiated to effect repairs.

l On April 12, initial repair of the leak was completed by grinding cut and revelding the existing seal welds. The system was then hydro-statically tested to 500 psi, successfully. Heatup was conmenced at 2350 hours0.0272 days <br />0.653 hours <br />0.00389 weeks <br />8.94175e-4 months <br /> on this date. On April 13, with the main coolant system at 780 psi and k20 F, the same instrumentation thimble was again found to be leaking.

0 At 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> on April 13, a second cold plant shutdown commenced. The initial repairs were found to be sound; however, veepage type leakage was observed frcm the periphery of the flux vire tubes where they penetrate the thimble seal back-up plug.

Leakage vould be experienced at this

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'^ cation if a failure occurred at the thimble back-up plug seal, in conjunction with a concurrent failure in either a flux vire tube within i

j the reacter vessel, or in the primary seal of t' flux wire thimble.

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l Repair of tnis leak was effected by disconnecting the flux vire l

tubes and adapting a achedule 160 stainless steel 3" diameter pipe section and cap to cover the leak area and velding this unit to the thimble.

j Repairs were completed on April 15 and a pressure test at 2k00 psi was performed, successfully.

The maintenance outage was concluded and the generator <as phased j

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,,n the line at 0810 hours0.00938 days <br />0.225 hours <br />0.00134 weeks <br />3.08205e-4 months <br /> on April 16.

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l The seventh vapor container air charge surveillance period was j

l terminated with the reacter shutdown on April 11.

The measured leak rate i

for this period was 0.0225% per day. The eighth air charge to the vapor container was completed on April 18.

The leakage cate during the current surveillance period has been normal.

During the period, the primary to secondary leak rate increased from 58 to 115 gallons per day. Analytical measurements indicate that the principle leaksge is occurring in the No. L steam generator with a minor contributi.n frem the No. 1 unit.

8 Plant Abnormal Occurrences There were no plant abnormal occurrences during the month of April, l

1969 l

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1: Plant load Reductions lApri' 1 (1145 - 1505)

Load reduction to 90 M4e a r tube leak-check in the east main condenser.

I Four tubes were plugged.

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April 23 (1505 - 16h0)

Load reduction to lh9 M4e due to electrical storm.

1 Plant Shutdowns Shutdown No. 99-7-9 4/11/69 h/16/69, unscheduled cold plant shutdown; repair leak in north incore instrumentation reactor head penetration. Shutdown' duration:

113 hours0.00131 days <br />0.0314 hours <br />1.868386e-4 weeks <br />4.29965e-5 months <br />, 59 minutes.

Plant Maintenance l

The following is a list of pertinent maintenance items performed.

by tue plant staff during the month of April, 1969 Items 1 'hrough h were performed during the April 11 - 16 outage period.

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1.

Six new brush holders vere installed on the exciter commutator.

I 2.

Packing was replaced in two shutdown cooling valves.

l 3.

New seals were installed on the shutdown cooling pump.

4.

The number two feedwater heater was opened for inspection; five tubes J

were plugged.

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New diaphrager, were installed in the No. I waste. gas compressor.

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6.

Preparation vas initiatec for the. refinishing of the spare set of l

1 reactor head studs.

7.

Work continued on installstion of the fire detection system.

5 8.

The non-return valves for both a txiliary boilers were inspecte:d and lapped.

Instrumentation and Control-l l

The following is a list of pertinent instrumentation <and control, maintenance items performed by the plant. staff during the month of April, 1969 1.

The incore instrumentation test peogram was continued.

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The plant TCUR temperature channels were recalibrated.

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Testing and installation of the fire detection system components was continued.

Reactor Plant Performance The foAlowing parameters were determined by means of incore instrumentation.

I 551.0 FMt; 513.3 F Tavg; Control Red Group A, B, C, D 9 90 3/8"; o ppm boron.

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t 4.21 Mininum DNBR

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559 5 F Maximum outlet temperature

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Chemistry W

and 9 73 respectively until April 11 when the reactor was shutdown and the The main coolant ammonia concentration and pH averaged 11.3 ppm i

cystem was borated to 880 ppm.

Due to the boron addition and the radio-lytic decomposition of ammonia the system pH averaged 6.80 during the shutdown.

Following reactor startup on April 16 the main coolant system was diluted with 70,000 gallons of water which reduced the boron con-centration to 27 ppt.

The remaining boron was removed by anion exchange and the ammonia coacentration was increased to as 12 ppm thereby raising the pH to 9.7 The main coolant average beta-gamma activity and crud levels in :reased from 7.h9 x 10-2 uc/ml and 0.09 ppm prior to shutdown, to a max:mam of 3 98 x 10-1 ue/ml and 3h.0 pps during shutdown. After i

startup, system purification reduced beta-gamma activity and crud level i

to T.23 x 10-2 uc/ml and 0.04 ppm, respectively.

l The main coolant tritium concentration was reduced from 1.68 uc/ml to 7.57 x 10-2 ue/ml cy the 70,000 gallon boron dilution. At the end of the period, the tritium concentration was h.85 x 10-1 uc/ml.

j The iodine - 131 specific activity was 2.65 x 10-5 ue/ml and the iodine 131/133 atomic ratio was 0.59 indicating the absence of. detectable fuel defects.

A representative crud sample collected before shutdown on April 11 had the following radiochemical analyses: dpm/cg crud I

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_h-O cr-51

. Mn-5h-Fe-59 1.56 x 107 6.60 x 106 1,oh x 107 co-58 co-60 6 Ag-110M l

' h.78 x 107 4.85 x 104 I

9 14 x 10 After plant startup, a representative crud sample collected on i

April 23, had the following radiochemical analyses: 'dpm/mg crud l

cr-51' Mn-Sh Fe-59 7

7 l-1.87 x 107 1.85 x 10 1.80 x 10 4

l co-58 co-60 Ag-110M 4

1.21 x 100 -

2.13 x 107

-7.82 x 10 g

A main coolant gas sample, collected on April 8.had the following radiochemical ana'.yses: uc/cc gas Xe-133 Xe-135 Ar kl 4.27 x 10-3 9.67 x 10-3 9 76 x 10-2 Health and Safety W

consisting of 54 drums with a total activity of 166.h me.

One shipment of radioactive vaste was made during the period, 1

Waste disposal liquid releases totaling 88,720 gallons contained 0.168 me of gross beta-gamma activity and 20k.86 curies' of tritium.

%= ecus releases during the period were 357.6 me of gross beta-gamma activity _and 116.5 me of tritium. An additional h.84 curies of tritium vapor was purged from the vapor cont.ciner through the primary vent stack to the. environment.

1 during the period. :3econdary plant water discharged totaled h22,471 gallons containing 0.458 rac of gross beta-gamma activity and 10.49 curies of tritium.

Work area radie'~on levels during repairs to the north incore

. instrumentation thimble were 300 - 500 mr/hr after shielding was installed.

Radiation exposure doses for -Yankee plant personnel, as measured E

by film badge, for the month of - April,1969 vere as follows:

Average accumulated exposure dose:

21h mrem.

Maxiram accumulated exposure dose:

950 mrem.

Operations-

.17tached is a summary of plant operating statistics and a plot of 4

daily average load for the month of April, 1969 A revised " Operating Summary' for. March, 1969 is included in this report, correcting an error in the Elect 2ical-Net _0utput - To Date. The-erroneous total of 8,772,777,337 KWH has been corrected to read 8,772,777,837 KWH.

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t YAliKFE ATOMU? ELECTRIC COMPANY

_OF3Jg"'ING DGC'.A?Y March 1969 MONTis YEAR TO DATE ELECTRICAL Gross Generaticn KWH 134,53h,500 386,783,600 9,390,5L5,<.9

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Sta. Service (While Gen. Incl. Lossec)

KWH 8,036,191 23,173,304 G7,767,503 KWH 126,h98,309 363,610,296 8,772,777,337*

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Net Output

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Station Service 5 97 5 99 6.58

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Sta. Service (While Not Gen. Incl. Lossec) h9 72,711 h35,099 26,718,749 Ave. Gen. For Month (74h.00)

KW 180,826 i

l Ave. Gen. RunninC (733.03)

KW 183,532 4

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PLANT PERF0FMANCE Net Plant Efficiency 29 20 29 24 28.LO l

btu /KWH 11,683 11,672 12,017 l

Net Plant Heat Rate Plant Capacity Factor 97 05 95 96 75 25

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Reactor Plant Availability 5

98.53 97 23 84.30 a

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i MONTH CORE VII TOTAL NUCLEAR I

HRS 735 98 7,857 95 62,965.3T i

Hours Critical Times Scrammed 0

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f Burnup bMD/MfU 8'(3 71 9,251.62 Core Average l

FMD/MfU reg on Average i

i A (INNER) 951.005 9,671.329 27,5L.e; B ( MIDDLE) 1,023.676 10,838.718 20,22u._2 C (OUTER) 696.3B1 7,h01.950

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o D (Z1RCALOY) 866.723 9,3S1.h53 9,.2 32. : e l

i Note:

Reported in error on March, b69 Operation Report No. 99

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YANKEE ATOMIC ELECTRIC COMPANY - OPERATING SUWARY April 1969 MONTH YEAR TO DATE EI.ECTRICAL Gross Generation WH 102,661,700 489,445,300 9,h93,207,100 sta. Service (While Gen. Incl. Losses)

KWH 6,543,391 29,716,695 624,310,954 KWH o6,118,309 459,728,605 8,868,896,146 Net Output Station Service 6.37 6.07 6.58 O

Sta. Service (While Not Gen. Incl. Lo",ses)

KWH 36h,345 799.hhh 27,083,094 Ave. Gen. For Month (719 00)

W 142,784 Ave. Gen. Running (605 0M W

169,683 PLANT PERFORMANCE Net Plant Efficiency 28.77 29 14 28.41 Net Plant Heat Rate btu /KWH 11,862 11,712 12,012 Plant Capacity Factor 77.43 91.33 75 27 Reactor Plant Availability 84.15 93 96 84.30 MONTH CORE VII TOTAL NUCLEAR s Crit HRS 614.03 8,hT1 98 63,5 9 40 Burnup Core Average WD/MTU 673.66 9,925 28 WD/MTU Region Average A (INNER)

Th0 966 10,h12.295 28,266.57 B (MIDDLE) 785 142 11,623.860 21,611.29 C (OUTER) 540.417 7,942.367 7,942.37 D (ZIRCALOY) 670.015 10,051.h73 10,051.h7 D

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