ML19351E262

Operation Rept 125 for May 1971

ML19351E262
Person / Time
Site:	Yankee Rowe
Issue date:	06/18/1971
From:	YANKEE ATOMIC ELECTRIC CO.
To:
Shared Package
ML19351E261	List: ML19351E260 ML19351E262
References
NUDOCS 8011260394
Download: ML19351E262 (8)

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I YANKEE NUCLEAR POWER STATION f

I OPERATION REPORT NO.125 l

For the Month of j

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l May 1571 i

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i Submitted by YANKEE ATOMIC ELECTRIC COMPANY Westboro Massachusetts June 18, 1971 8011260 [

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O This report covers the operation of the Yankee Atomic Electric Company at Rove, Massachusetts for the month of May,1971.

Atthe start of the period, plant load was 185.1 MWe. One scheduled plant shutdown occurred May 8 and 9 for the purpose of plant I

maintenance, testing and operator training. Load reduction was commenced at 05h0 hours on May 8.

At a plant load of h5 IWe the reactor scrammed and the turbine tripped; initiated by a false dropped rod signal (Abnormal Occurrence No. 71-1, described below). Following completior, of the training period on May 9 the turbine generator vas phased to the high line at 0524 hours0.00606 days <br />0.146 hours <br />8.664021e-4 weeks <br />1.99382e-4 months <br />. The reactor power level which was 485 IWt at 06h2 hours on May 9, was increased to 600 MWt on May 10 at 0755 hours0.00874 days <br />0.21 hours <br />0.00125 weeks <br />2.872775e-4 months <br />. During the balance of the period plant 1 cad varied between 182 9 MWe and 185.9 MWe as j

the circulating water inlet temperature fluctuated between h8 F and 38 F.

i The fourth, Cora IX vapor container air leakage surveillance period was terminated coincident with the end of the report period; with normal leakage noted.

Two shipments of spent fuel, each containing nine assemblies removed during the Core '/III-IX refueling period, were made during the report period. The dates of shipment were May 10 and 26. The fuel shipments

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were the 33rd and 34th in the series bringing the number of assemblies shipped in the ten assembly cask to 316 and the total number of assemblies shipped to date to 332.

Plant Abnormal Occurrences Abnormal Occurrence No. 71-1 " Plant Trip".

On May 8, while operating at a reduced load of h5 MWe preparatory to a scheduled reactor shutdown, the reactor scrammed and the turbine tripped.

j Investigation shoved that the reactor scram and subsequent plant trip were precipitated by a false dropped rod signal from the nuclear, j

4 intermediate range, power channel No. 3.

The false signal occurred during l

instrument recalibration when tha detector cable was removed from the

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intermediate range amplifier section of the No. 3 channel, before first i

lowering the dropped rod. contact.

A survey of plant conditions, following the plant trip, revealed no adverse or unsafe conditions, j

Following reca-stion of the nuclear, source and intermediate range channels, operator

.ning was commenced.

I Plant Load Reduction i

May.5 (1140-1210):

Plant load reduction to 177 MWe for turbine control valve exercising.

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May 14 (1146-1353):

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Plant load reduction to 135 MWe to facilitate repairs on the turbine left hand control line drains valve.

May 19 (1145-1220):

Plant load reduction to 177 MWe for turbine control valve exercising.

May 26 (1145-1220):

Plant load reduction to 177 MWe for turbine control valve exercising.

Plant Shutdowns Shutdown No. 115-9-71: 5/8/71 - 5/9/71, plant shutdown for plant mainte-nance, testind and operator training. Total outage time: 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br />, 5 minutes.

Plant Maintenance 1

The following is a list of pertinent maintenance items performed by the plant staff during the month of May, 1971.

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1.

Refurbishing of ix control rod drive shaft-dash pot assemblies, j

removed during the Core VIII-IX refueling period, was completed.

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2.

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

9 3.

l During the May 8-9 shutdown the following maintenance items were j

performed:

I a.

The tubes in the East water box of the main condenser were cleaned with scraper plugs; and leak tested. No leaking tubes were detected.

b.

Vibration readings were taken of all four main coolant pumps. All readings were normal.

c.

The inboard glands on the No.-1 and No. 3 boiler feed pumps were repacked.

d.

The generator exciter commutator was stoned during turbine coast-i down.

Instrumentation and Control t

I The following is a list of pertinent instrumentation and control maintenance items performed by the plant staff during the month of May,1971.

1.

A new range switch was installed on the reactor incore thermocouple temperature recorder.

l 2.

The main coolant bleed line radiation monitor was recalibrated as l

required.

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The' annual installation of-a Dearfield River water temperature recorder in~the Sherma*, Station tailrace, was completed.

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h' Reactor Plant Performance O

The following parameters were determined by means of incore instrumentation:

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599 Ist; 526.5 F Tavg; Control Rod Group A @ 84, B,C,D @ 88 ;

i 707 ppm boron.

Fq 1.9

=

FAH = 2.0 Minimum DNBR = 3.h L

Maximum Outlet Temperature = 591.0 F Secondary Plant Performance Feedvater heater terminal differences were as follows:

No. 1 = k.8 F No. 2 = 6.7 F No. 3 = 5.h F The condenser performance was as follows:

j 185.h MWe; 1.12" Hg B.P.; 598.5 !Nt; h0.7 F C.W. in; TTD = 24.8 F; l

cleanliness factor = 85.h%.

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Chemistry I

i The main coolant boron concentration was reduced from 772 ppm to 633 ppm to compensate for normal core depletion.

5 The main coolant pH averaged 5.39 during the period.

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

averaged 1.06 x 10-1 uc/ml and 0.02 ppm respectirely.

The main coolant tritium concentration averaged 2.97 ue/ml during l

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the report period, f

The iodine-131 specific activity averaged 5.43 x 10 h ue/ml and the lodine 131/133 atomic ratio averaged 2.26, indicating no significant change in the magnitude of fuel clad defects during the month.

A crud sample for the month collected on May 12, had the following radiochemical. analyses: dpm/mg crud Cr-51 Mn-54 Fe-59 5

6 1.36 x 107 7.57 x 10 1 96 x 10

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Co-58 C -60 Ag-110M 6

5.88 x 10 1.hh x 106

.h.18 x 105 A main coolant gas sample, collected on May 25, had the following radiochemical analyses: uc/cc Xe-133 Xe-135 Ar-41 1.68 1.07 x 10-1 5.34 x 10~1 Health and Safety Two shipments of spent fuel with respective total activities of 1h.h5 megacuries and 10.81 megacuries were made during the period.

Waste d!sposal liquid releases totalled 21,788 gallons containing 0.008 me of gross beta-gamma activity and 87.60 curies of tritium. Gaseous releases during the period totalled 1.593 curies of gross beta-gamma activity. Secondary plant water discharged totalled 477,371 gallons containing 0.066 me of gross beta-gamma activity and h.797 curies of tritium.*

Radiation exposure doses for Yankee plant personnel as measured by film badge for May, 1971 vere as follova:

Average accumulated exposure dose: 68 mrem I

Maximum accumulated exposure dose: 440 mrem i

A statement in regard to secondary plant discharges was omitted from the April, 1971 Operation Report No. 124. Such values for April were i

393,h65 gallons discharged, containing 0.0h1 me of gross beta-gn=ma i

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activity and 1.881 curies of tritium.

Operations Attached is a summary of plant operating statistics and a plot of daily average load for the month of May, 1971.

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YANKEE ATOMIC ELECTRIC COMPANY - OPERATING

SUMMARY

May 1971

. ELECTRICAL MONTH YEAR t -

"TO DATE-Gross Generation

'KWH 131,985,300 656,749,900.

12,152,621,200; Sta.-Service (While Gen. Incl. Losses)

KWH 7,886,243 39,231,690.

787,256,715=

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.Het Output

.KWH 12h,099,057-617,518',210 ~

11,365,364,h85 l:

Station Service 5 98 5.97-6.48 Sta. Service (While Not Gen. Incl. Losses) KWH 147,300' 340,883

.32,629,738?

Ave. Gen. For Month (Thh)

.KW 177,399.6

. Ave. Gen. Running-(721.92)

KW-182,825.h PLANT PERFORMANCE Net Plant Efficiency 28.98

-28.99

-28.51

' Net Plant Heat Rate btu /KWH 11,776

.11,772

-11,970 Plant Capacity Factor' 95 93 97 99

-76.02-4.

I Reactor Plant Availability.

97.19 98.71-

.84.54 8,'

NUCLEAR MONTH CORE IX TOTAL Hours Critical HRS 728.90 4,393.71 79,358.11 Times Scrammed 1

2 63 Burnup Core Average MWD /MPU 858.89 5,168.27

' Region Average-MWD /MTU A (INNER) 847.69 h,986.60 22,190.27

.E (MIDDLE) 1,003.3h.

~6,095.78 14,837.63 C (OUTER) 715.98 4,261.48 h,261.48 D (ZIRCALOY)

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