ML19351E307
| ML19351E307 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 06/22/1970 |
| From: | YANKEE ATOMIC ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML19351E306 | List: |
| References | |
| NUDOCS 8011280056 | |
| Download: ML19351E307 (7) | |
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Lj This report covers the operation of the Yankee Atomic Electric
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Company at Rowe, Massachusetts for the month of May,1970.
During the period plant load varied between 175.2 !E. and 185.9 MWe as the circulating water inlet temperature fluctuated between 61 F and hl F.
During the report period, accountable primary to secondary leakage developed, and at the end of the period had increased to approximately 97 gallons per day.
One, unscheduled, plant shutdown occurred during the period, initi-ated by a reactor scram and subsequent turbine trip on May 2 at 2355 hours0.0273 days <br />0.654 hours <br />0.00389 weeks <br />8.960775e-4 months <br />.
Further discussion of this shutdown is presented as Abnormal Occurrence No. 70-2, this report.
A second, scheduled, plant shutdown occurred on May 15 at 2157 hours0.025 days <br />0.599 hours <br />0.00357 weeks <br />8.207385e-4 months <br /> for the purpose of effecting repairs to the No. 1 feed water heater. The heater had been isolated from the feedwater system since May 12, due to ex-cessive tube leakage. Leakage by the isolation valves for No.1 feedvate.
heater precluded repair at power. Upon opening the heater, seven tubes were found to be leaking and were plugged. Following completion of repairs and reinstallation of the heater manway diaphragm and cos r on May 17, the turbine generator was phased on line and the plant was loau to Sho MWt at 1730 hours0.02 days <br />0.481 hours <br />0.00286 weeks <br />6.58265e-4 months <br />, that date.
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The fourth, Core VIII vapor c;ntainer air leakage surveillance period C/
was terminated, and the fifth such pe.od was co=menced on May 29.
Leakage during the entire report period was..artA1.
Class B and Class C vapor container penetration leak testing van commenced in May. At the end of the report period, approximately 70% of the pertinent penetrations had been tested with favorable results.
Plant Abnormal Occurrences Abnormal Occurrence No. 70-2 " Plant Trip" On May 2, 1970 the plant was operating at a power level of 598 MWt, when at 2355 hours0.0273 days <br />0.654 hours <br />0.00389 weeks <br />8.960775e-4 months <br /> the reactor scra=med; the turbine tripped; and the 115 KV oil circuit breakers opened.
A survey of the memory and scram sequence panels indicated that the trip was caused by a main coolant low flow signal. The No h main coolant pump flow indication in the control room was lov, confirming that a low flow signal initiated the trip.
Since the other loop parameters were normal, the pump was left in service.
The plant was placed in a hot standby condition, followed by an in-spection in the vapor container which revealed no abnormal conditions.
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The reactor was taken critical and the turbine was phased on line
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l at 0505 hours0.00584 days <br />0.14 hours <br />8.349868e-4 weeks <br />1.921525e-4 months <br /> on May 3.. The plant was loaded to h50 MWt and maintained at I
this load until May b when main coolant loop No. 4 was removed from service L
to permit internal inspection of the flow signal transmitter. A voltage
~ dropping resistor was found to have moved in its holder such that normal
. vibration could cause an intermittent partial ground on the primary coil of r
the transmitting LVDT. Since this may not have been the only fault, the i
entire LVDT was replaced 1,o pemit shop, testing. The amplifier was rec-
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brated and proper operation of the lov flow alam ana scram bistable was l
cont'irmed. The No. k main coolant loop' was returned to service and loading j
of tne plant to full power was completed at 23ho hours on May h.
j Plant Load Reductions May 12 (0900):
Load reduction to 176 MWe to permit removal from i
service of leaking No. 1 feed water heater.
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May 30 -(0915-1800):
. Load reduction to 110 MWe for reason of electrical maintenance in the Harriman Station switchyard.
ll Plant Shutdowns Shutdown No. 108-8-70: 5/2/70, plant. trip due to false signal from failed l
safe No. h loop lov flow signal transmitter. Total i
outage time:
5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />, 10 minutes.
4 Shutd~;n Fo. 109-8-70:
5/15/70, scheduled plant shutdown to permit plugging i
of leaking tubes in No. 1 feed water heater. Total
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outage time:
hl hours, h8 minutes.
Plant Maintenance The following is a list of pertinent plant raaintenance items j
perfomed by the plant staff during the month of May,1970.
i 1.
An electrical overhaul was perfomed on the motor for the shutdown j
cooling pump.
l 2.
A travel limit alam was installed on the Controlled Area yard crane.
.t 3.
The No. 1 charging pump was repacked, and refurbished plungers were installed.
h.
A new after. cooler was installed for the No.1 control air compressor.
5 Seven tubes were plugged in the No. 1 feed-water heater during the May 16.- 17 shutdown.
Instrumentation and Control-The following'is a list of pertinent instrumentation and control maintenance items perfomed by the plant staff during the month of May,1970.
- 1..The No. k main coolant lo'op flow transmitter LVDT was replaced.
3-i 2.
ihe range selector switch for the incore themocouple temperature recorder i
vns replaced; and the recorder was recalibrated as necessary.
Reactor Plant Performance The following parameters were determined by means of incore instru-l mentation:
598.0 int; 519.5 F Tavg; Control Rod Group A @ 68, B,C,D, @ 89 ;
31h ppm boron.
2.5 F =
q F
= 2.3 aH Minimum DNER 3.0
=
590 F Maxi =um Outlet Temperature
=
Secondary Plant Performance l
l Feedwater heater terminal differences were as follows:
l 11.8 F No. 3 i
No. 1 = 5.5 F No. 2 5.0 F
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Note: No.1 feedwater heater removed from service May 12, 1970.
l The Condenser performance was as follows:
I 183.8 !Ge; 1.70" hg. B.P.;
586.h !Gt; 50.h F C.W. in; TTD = 22 71 F; cleanliness factor = 83.22%.
Chemistry i
i The main coolant boron concentration was decreased from 361 ppm to 2h8 ppm during the period to compensate for core depletion. The average
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main coolant pH vas 6.h2.
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i The main coclant average gross beta-ga=mt acti*ity and crud level vere 1.09 x 10-1 ue/ml and 0.01 ppm respectively.
i The main coolant tritium concentration decreased from 1.98 ue/ml to i
1.63 ue/ml during the period due to dilution.
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The average iodine-131 specific activity was 3 99 x 10 ue/ml and the iodine 131/133 atomic ratio was 0.51 indicating the absence of detectable fuel defects, i
l A representative crud sample for the month, collected on May 11, l
had the following radiochemical analyses: dpm/mc crud.
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Cr-51 Mn-54 Fe-59 I
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k 2.95 x 10 5.32 x 10 1.03 x 10 Co-58 Co-60 Ag-110M h.12 x 10I D
6 9.86 x 10 1.46 x 10 A main coelant gas sample collected on May 26, had the following radiochemical analyses: ue/cc gas.
Xe-133 Xe-135 Ar-k1 6.12 x 1,-3 8.29 x 10 1.58
-3 Health And Safety One shipment of lov level radioactive vaste containing a total activity of 100.8 cc was made during the period. The shipment was made up of 57 drums and 118 ft3 of miscellaneous vaste materials.
Operation Report No. 112 (April,1970) reported one shipment of 56 drums of lov level vaste, containing a total activity of 109.5 me, was made during the period. The values stand corrected to read two shipments; 112 drums; and 265.0 me, respectively.
Waste disposal liquid releases totalled 26,2h0 gallons containing g
0.015 me of gross beta ga=ma activity and h7.35 curies of tritium. Gaseous f'
i releases during the period totalled 1.628 curies of gross beta-gamma activity.
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Secondary water discharged totalled 326,664 gallons containing 1.593 me of gross beta-ga=ma activity and 8.55 curies of tritium.
Radiation exposure doses for Yankee plant personnel, as measured by film badge, for the month of May 1970 were as follows:
Average accumulated exposure dose:
120 mrem Maximum accumulated exposure dose:
660 mrem Operations Attached is a summary of plant operating statistics and a plot of daily average load f3r the month of May, 1970.
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D.1 [iJ A !:J? MIS !OAD for May 1970 (a) Shutdown No. 108-8-70 (b) Shutdown No. 109-8-70 200 -
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YANKEE ATOMIC ELECTRIC COMPANY - OPERATING
SUMMARY
May - 1970 ELECTRICAL MONTH YEAR TO DATE Gross Generation KWH 124,558,400 605,303,300 10,820,961,80v Sta. Service (While Gen. Incl. Losses)
KWII 7,h73,981 35,920,058 705,924.922 Net output KWH 117,084,419 569,383,242 10,115,036,878 Station Service 6.00 5 93 6.52 Sta. Service (While Not Gen. Incl. Losses) KWH 323,029 1,224,995 30,132,92h Ave. Gen. For Month (Thh)
KW 167,h17 Ave. Gen. Running (696.29)
KW 178,889 PLANT PERFDRMANCE Net Plant Efficiency 29 12 29.62 28.47 Net Plant Heat Rate btu /KWH 11,720 11,522 11,987 4
Plant Capacity Factor 90.04 88.42 75.30 8
Reactor Plant Availability 5
99.78 92.h3 84.23 NUCLEAR MONTH CORE VIII TOTAL Hours Critical HRS 7h2.34 5,776.87 71,596.65 g
Times Scrammed 1
3 60*
Burnup Core Average M4D/fRU 806.08 6,61h.84 Region Average MdD/MrU A (INNER) 761.2k 6,045.23 25,976.13 B (MIDDLE) 919.74 7,588.h6 19,624.52 C (OUTER) 697.19 5,6T9.70 5,679.70 D (ZIRCALOY)
- Note: This number has carried an error of one since Operations Report No. 95
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