ML19351E159

Operation Rept 25 for Jan 1963

ML19351E159
Person / Time
Site:	Yankee Rowe
Issue date:	02/20/1963
From:	YANKEE ATOMIC ELECTRIC CO.
To:
References
NUDOCS 8011250683
Download: ML19351E159 (11)

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OPERATION ~ REPORT NO.'25 1

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JANUARY 1963 1

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Submitted by.

L it YANKEE ATOMIC ELECTRIC COMPANY j'

' Boston Massachusetts et-i February 20, 1963 i$-

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r-2 7,V This report covers the operation of the Yankee Atomic Electric Company plant at Rowe, Massachusetts for the month of January 1963.

During the first eight da; s of the month the plant remained at the licensed full power level of 5ho MWt. On January 9, the reactor power level was reduced to h85 MWt in order to stabilize plant conditions prior to conducting a boric acid test at power.

Minor leakage from the charging line relief valve increased sub-stantially on January 13, and investigation of the condition led to a plant shutdown on January lb, for replacement of the valve. The_ plant was held in hot standby for operator training and control rod drop tests while the valve replacement was made. Control rod groups 1 and 3 were drop tested and drop times were measured on these groups during the shutdown. In the ensuing startup, at'a load of approximately 20 Ele, a spurious reactor scram (7

occurred. It was observed at the time that control rod No.17 did not scram V

from its fully withdrawn position. After a thorough check and testing of nuclear instrumentation memory lights which gave no indication of the cause of the scram, it was concluded that the scram signal originated in the secondary plant. Rod No.17 was freed by driving it into the core approx-imately 3 inches with the mechanism pull down coil in service. In view of the core lifetime and shutdown margin available, it was decided that no hazard existed and preparations were made to return the plant to the line.

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Shortly thereafter plant load was restored following a routine

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startup and phasing of the generator to the line.

The discovery of a leaking primary system drain valve on January 15, coupled with the difficulty with No.17 rod the previous day led to a decision to remove the plant from the line to repair the valve and further test the control rods. After informing the Division of Licensing and Regulation of developments, all rods except No.17 were dropped once from the fully with-

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drawn position and operated perfectly. Rod No. 17 was dropped three times

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since the first drop showed that it did not start to fall until all other rods in its group had reached the fully inserted position. On the second and third drops, no difficulty was noted. The results of these additional tests were conveyed to the A.E.C. with a request to resume operations sub-ject to restrictions on control rod motion and with periodic testing. The request was approved and at 5:06 P.M. en January 15, the generator was rephased to the line and by 6:15 P.M. the plant power level was restored to h85 M4t.

The behavior of control rod No.17 was similar to that experienced with rod No. 9 during Core II st,rtup (Operation Report No. 21). These difficulties are at,tributed to interference between the control rod drive shaft locking cap and a weld at the upper extremity of the travel housing.

Since this potential interference can occur only at the fully withdrawn position (90 inches), it was decided to limit the maximum withdrawal of all rodsto887/8 inches. Also initiated during the period was a procedure

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. calling for' routine exercising at two week intervals of all control rods in Lthe =winm withdrawn position. This' procedure will be in effect for the remainder of Core II life and will consist of running in' individually a minimum of 18 rods which are at. the 88 7/8 inches withdrawn position.

Following the return of.the plant to the line on January 15, a power level of h85 Ifdt was established and maintained. ~ On January 2h,.

Commission approval of Proposed Change No. 31 was received thus-waiving temporarily the plant. technical specification provision relating to main welant boron concentration at power. By virtue of'the waiver, approval was granted to borat,e the reactor coolant up' to'h00 ppm boron at power levels up to 5h0 PMt.

On January 28, a boric acid solution was injected into the main-coolant system msulting in an ultimate concentration of approximately

.O-h00 ppm boron. At the end of the period the boric acid run was still in V

progress with the coolant boron concentration at approximately 396 ppm.

During the period twenty-three Core I control rods were loaded into a shipping can'in the spent fuel _ pit. Upon procurement of a shipping cask, the can and its contents will be shipped off-site for disposal. The remaining Core I control rod will be examined off-site under an A.E.C. contract.

Shipment of this rod is~ expected to be-made at a future date.

GV Nine new fuel assemblies were received ~at the site during the period bringing to 27 the total of new assemblies now in storage.

Plant Shutdowns

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Shutdown'No. 53-2-5 1/lh/63 A 16 hour1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> 58 minute shutdown for replacement of a leaking charging line relief valve.

-Shutdown No. W-2-6_

1/lh/63 - A 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> 33 minute shutdown resulting from a spurious reactor scram.

Shutdown No. $$-2-7 1/15/63

' A 6 hour6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> h minute shutdown for repair of leaking primary system drain valve and control rod testing.

Reactor Scrams Scram No. 33-2-3 1/1h/63 an automatic reactor scram from a power level of '92 FMt. - The reactor scrammed on a spurious signal believed to have originated in the' secondary plant.

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Maintenance

.Following is a-summary of major activities carried out by plant maintenance personnel during January.

1.

Replaced chargin line relief valve SV-209 as a result of excessive leakage.

2.

Fabricated and started testing a set of underwater lights for use in refueling.

-3.

Installed cooling coils in the upp,er motor bearing of all three-condensate pumps.

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Repaired generator hydrogen leaks at the gas dryer and-at several t'~l -

electrical penetrations.

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Inspected new control rod shipping can and loaded twenty-three used control rods in the can.

6.

Eliminated a flange leak in the right hand moisture separator.

7.

Insulated and neat traced the steam generator sample lines.

8 Performed tests to determine the qualities of a possible flux wire lubricant.

9.

Started reconditioning accessible sections of the flux wire system.

10. Replaced bearings and inspected turbine gland steam exhauster motor.

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Chemistry Because of a marked increase in the spent fuel pit ion exchanger effluent activity, the ion exch e capsule was replaped. The effluent activity decreased from h.0 x 10- nc/ml to 2.5 x 10-2 nc/ml following the change. Canning of twenty-three of the twenty-four Core I control rods resulted in a reduction in the specific activity of the pit water from 5.9 x 10-3 toh.5x10-hsc/ml. Removal of the remaining rod should result in a further reduction in the pit water activity.

Main coolant oxygen levels were below the point of-detection prior to adding boric acid to the main coolant system. Eighteen hours after boration, the oxygen content had risen to 200 ppb. Over the following six hours the oxygen level decreased to h0 ppb. A further reduction was noted and the oxygen levels were again below the point of detection by the end of

'.the period.

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-h-To establish equilibrium main coolant conditions for the start of.the bor'c acid test, the primary water purification system was shut down several day,* before the test began. As a result the main coolant specific activity increased from 1.3 x 10-1 activity increased from 2.8 x 10-3 pc/ml to 1.9 x 10 sc The Iodine-131

/ml to 2.7 x 10-2 pc/ml and the crud

-level increased from 0.26 ppm to.0.98 ppm.

ity reached equilibrium with no purification at h.8 x 10-2TheIodine-131sp/ml.

ecific activ-mc

?A main coolant gas analysis made before the boric acid -test indicated the following:

Ie 135-3.8 x 10 Sc/cc gas Kr - 85 1.5 x 10- pc/ccgas.

Xe -133 h.6.

Ec/cc gas C)

At the end of the period the main coolant boron concentration was V

396 ppm. In the ' January 28 to January 31 period no demineralized make up -

water was added to the primary system in order to maintain the boron con-centration as stable as possible.

Reactor Plant Performance On January lb, drop ti2ne measurement on 6 control rods chosen via pd -the periodic test schedule indicated normal' drops.- During the control rod drop tests conducted on January 15, the elapsed drop time was measured on

.the remaining 18 rods including rod No. 17 which showed evidence of sticking.

As mentioned previously, the first time rod No. 17 was dropped it did not fall until the other rods in its group had reached bottom. On the' succeeding drops, rod No. 17 released properly and the' drop time was within acceptable limits. The drop time from a 90 inch to a 6 inch position averaged 1.55 seconds during :these tests compared to 1.52 seconds at the start of Core II operation'and'1.h8 seconds' at the start of Core I operation.

Analysis of core reactivity during January indicated that the overall burnup rate for the' ten days prior to the start of the boron test was about half the' normal burnup rate. Variations in the' rate were observed, the most pronounced occurring after a load swing for power coefficient testin6 Following the load swing there was a period of approximately 2h hours with an above average loss followed by two days of reactivity gain.

The two. days prior to the start of the boric acid. test indicated a near nor-mal burnup rate.

totaled a 12 x 10-4 &y loss for the 2h hours following boric acid injection The react;Lvit 8.

A' gradual ga4.n in reactivity occurred during the next three days increasing core reactivity atla rate of approximately

- 3 x 10-h 6(O/_ day.

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V Turbine Plant Performance No difficulty was encountered during the period with the condenser

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circulating water siphon. An air removal pump, tank and piping connections

.are in-place with only the final connection to the air removal pipes in the circulating water discharge line remaining to be made.

Cooling coils were installed in the thrust bearing oil cavity of each. condensate pump during the month. High bearing temperatures had re-quired relatively frequent changing of oil and the cooling coils are designed to correct this condition.

Health and Safety Liquid waste with a total activity of 0.36 millicuries was dis-charged from the plant during January. Gaseous waste containing 2.6 curies was discharged during the same period. Two drums of solid waste containing approxinately 3.5 millicuries were prepared while no solid waste was shipped.

The concentration of waste products di9ei:arged from the plant was at all times well below the naximum permissible.

Seven packages consisting of main coolant liquid and crud samples p

taken during the boron test were shipped off-site for analysis during V

January. The total activity content of the samples was approximately 2 millicuries.

Following is a summary of radioactive waste discharges and ship-ments for the year 1962; Liquid 7.6 mil 11 curies Gas 21.7 curies j

Solid (517 drums) 1h80 millicuries Contaminated tools and equipment which had been stored in several ot.i door areas were moved into the new storage building'during January.

Typical radiation levels measured near the surface of the jacking mechanism, reactor guide studs and drWe shaft storage rack were 100-500 mr/hr(gamma) andh0-600mr/hr(beta). Levels of 20-50 mr/hr (gamma) and 5-10 mr/hr (beta) were measured on the stacking plates and the reactor head gasket lifting fixture. The building has been posted as a high radiation area and a radiation work permit is required for entry.

of 2 x 10 gn air sample taken from the incinerator stack indicated an activity

.to7x10-7pc/cc. The act,1vity was identified as Ag-110m and is believed to be due to the burning of a section of hose which had been in the spent fuel pit. The radiation level on the hose was 3 r/hr.

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-Radiation levels in the area of the spent fuel pit during loadirg of Core I control rods into a storage and shipping can were on the order of 5 to 15 mr/hr. Levels'6f 10 mr/hr were measured on the manipulator crane, h5 mr/hr in the vicinity of the cooling pump and up to 150 mr/hr near-the hydraulic. Jacking pump.

The following contact radiation levels were measured during January:

Location

- Radiation Level on Contact No. 'l Charging Pump 35 mr/hr

'No. 2 Charging Pump 17 mr/hr No. 3 Charging Pump.

30mr/hr Charging Line (in pip' chase).

22 mr/hr Main Coolant Bleed Line (in pipe chase)-

~80 mr/hr' Activity Dilution Decay Tank 100-1000 mr/hr

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Waste Holdup Tank 100 1800 mr/hr

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Oas Surge Drum 0.15mr/hr Shutdown Cooling Pump 80mr/hr No.1 Purification Pump Drain Line 2 r/hr i

No. 2 Purification Pump Drain Line 1 r/hr Low Pressure Surge' Tank Discharge ~Line 300 mr/hr Low Pressure Surge Tank Bottom

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Ion Exchange Pit; 0.5-15 mr/hr Overflow from a main coolant sample sink caused a minor spill of main coolant sample water on the floor of the sample cubicle. The water ran down the cubicle floor drain and to the primary building sump tank system.

The total activity in the overflow liquid was 20. mil 11 curies and t k affected area was decontaminated after drainage of the. vater was completed. No sig-nificant personnel exposure was involved. To prevent such overflows in the l

future, the cubicle will be under visual observation durirg periods when the sample ~line is discharging to the sample, sink.

. Personnel exposure for Yankee plant personnel as measured by film badges for the fc11owing period 9 were:

Average Exposure Maximum Exposure Year 1962 2020 mr h790 mr Fourth Quarter of 1962 262 mr 1180 mr December 1962

~ 31 mr 170 mr' Continuous monitoring of off-site airborne activity during Janu -

ary indicated levels consistent with pre-operational values.

Special Tests'

. On the morning of January 28, ~ a boric acid solution was injected into.the main coolant system initiating a test to demonstrate the. use of boric acid in. the reactor coolant at power and in ' concentrations' up to '

h00 ppm of boron.

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With the exception of a-brief load swing for power coefficient

. determination, the reactor power level.was maintained essenticlly constant-for several-days prior to the test at the test power level-of h85 MWt.

4 Boration was effected smoothly and the desired concentration of 390-h00 ppm borc,n was achieved within a few hours. At a main coolant average temperature of 512 F, the pre-test rod group positions were as follows:

Group 1-887/8 inches withdrawn 2

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887/8 5

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During.boration Group 5 was withdrawn to 88 7/8 inches followed by gradual withdrawl of Group 2 which reached 65 $/8 inches some five hours after establishing the test boron concentration. The corresponding average coolant tempera %re was $1h0F.-

At the end of the period, with the test still in progress, the boron concentration remained between 390 and h00 ppm with Group 2 rods with--

drawr. to 671/8 inches and all other groups withdrawn to 88 7/8 inches.

L Tave, was 51h.5 F.

4-No oper.ating difficulties were encountered in the January 28 -

January 31 pericd. A complete report of the boro t test will be made after.

its conclusion.

Design Changes

. O The fo11ewins teer chemeee in 9 ent dee18n were comp 1eted durime 1

January:

I 1.

The waste gas surge drum pressure transmitter was relocated from a point outside the gas surge drum cubicle to an indoor-location in the gas compressor room. Relocation of the transmitter will prevent its exposure to severe temperature changes.

2.

A low level alarm was added to the waste gas header loop seal outlet leg. The alarm was added to detect water 1eakage from the loop seal and is set to respond when the outlet leg water level drops two inches below normal with an inlet leg pressure of six inches of water.

3.

The high neutron flux alarm on power range channels 6,7 and 8 has been-modified.slightly. The' alarm set point har, been lowered and g()

the alarm will now operate between 100% and 108% of power and provide a warning-that one of the bistables may be in a scram

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Changes in Operating Procedure

. One temporary change in opersting procedure was instituted during.

January. To reduce the possibility of :entrol rod sticking as discussed earlier. in-this report, the maximum rod withdrawal will be limited to 88.7/8 inches rather than 90_ inches. Furthermore, all rods in the maximum withdrawn position will be exercised at two week intervals. This self.

. imposed change in procedure will be in effect for the remainder of Core II.

life.

Plant Operations

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Attached is a' summary of plant operation statistics for the month of January 1963, and a plot of daily average plant load for the same period.

' Minor corrections' have~ been made to the Plant Operating Factor, To Date O

figure and the Equivalent Reactor Hours @ $1t0 MWt, To Date figure. The adjustments were occasioned-by revisions in the MWt output of Core I.

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1 IANKEE ATOMIC ELECTRIC COMPANT - OPERATING

SUMMARY

JANUARY 1963 EECTRICAL MONTH YEAR TO DATE Gross Generation KWH 112,516,'m 112,$16,000 1,813,988,000 Sta. Service (While Gen. Incl. Losses)

KWH 7,lll. Y 7,1h3,$0h-137,900,071 Net Generation KWH 105,372,h96 10$,372,h96 1,676,087,929 Station Service 6.35 6.35 7.60 Sta. Service (While Not Gen. Ir.cl. Losses)

KWH 18F:1.38 185,138 1h,153,976 Ave. Gen. For Month (7hh HRS..)

W 151,231 Ave. Gen. Running (718.h. HIS. )

W 156,620 PIANT PERFCRMANCE Net Plant Efficiency 29.h1 29.bl Net Plant Heat Rate Btu /WH 11,60h ll,60h Lbs. Steam / Net KWH 13.85 13.85 Circulating Water Inlet Temp.

Maximum F

37 Minimum 0F 33 Plant Operating Factor 89.18 89.18 6h.03 NUCEAR MONTH CORE II TO DATE Times Crit,ical 2

29 291 Hours Critical HRS 738.82 3228.3h 16,b75.77 Times Scrammed 1

3 33 Equivalent Reactor Hours @ $h0 MWt HRS 663.5 287h.6 10,791.7 Average Burnup of Core MWP/mtU 717.7 310).6 Control Rod Position at Month End Equilibrium at h85 MNt (h00 ppn boron)

Group 1 Rods out-inches 88 7/8 Group 2 67 1/8 Group 3 88 7/8

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Group h 88 7/8 Group 5 88 7/n Group 6 88 7/8

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YANKEE ATOMIC ELECTRIC COMPANY DATLY AVERAGE LOAD for JANUARY 1963

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(b) Shutdown No. $14-2-6 (c) Shutdown Ho. 55-2-7 i

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