ML19351E157

Operation Rept 26 for Feb 1963

ML19351E157
Person / Time
Site:	Yankee Rowe
Issue date:	03/29/1963
From:	YANKEE ATOMIC ELECTRIC CO.
To:
References
NUDOCS 8011250679
Download: ML19351E157 (19)

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YANKEE NUCLEAR PC'dFR STATION OPERATION REPORT NO. 26 J

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Submitted by YANKEE ATOMIC ELECTRIC COMPANY Boston Massachusetts March 29, 1963 O

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This report cov9rs the operation of the Yankee Atomic Electric (j

Company plant at Rowe, Massachusetts for the month of February 1963.

The plant remained in continuous operation throughout the priod and with the exception of a temporary load reduction on February 3, the reactor power level cas naintained at h85 Mrit until February 28, when power was increased to $h0 MNt.

The boric acid test at power, which commenced January 28, was still in progress at the beginning of the month with a main coolant boron concentration of approximately h00 ppm. Addition of demineralized make up water to the primary system on February 6 reduced the boron concen-tration to 360 ppm and a second make up addition on February 13 further reduced the boron concentration to 3h2 ppm. During a routine surging of the pressurizer on February lh, for the purpose of main coolat mixing, an oxygen concentration of 3.7 ppm was found in the main coolant.

It was noted that increases in the coolant oxygen concentration n(")

closely followed pressurizer surging operations. Furthermore, the oxygen concentration diminished quite rapidly when the cycling operation was terminated.

On February 15, boron removal from the main coolant was initiated to allow establishment of nomal nain coolant purification and to nerform additional chemical testing in regard to the presence of oxygen 4.. the main coolant system.

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By February 18, the main coolant boron concentration had been reduced to less than 1 ppm and periodic pressurizer surging was continued to explore the apparent relationship between the surging and the coolant oxygen level changes The investigation continued through the end of the period and the results are discussed in the CHEMISTRY sectica c# this report.

1 Borce removal on February 15. ended a 19 day period during which (V

the reactor had operated at power with boron concentrations as high as h00 ppm, A aiscussion of the boron test is included in this:eport in the SPECTAL TESTS seetion.

As described in the January 1963 Operation Report, 23 Core I control rods were inserted in an aluminum container and stored in the spent fuel pit pending their shipment off-site for disposal. Durirg the first week in February intermittent bubbling from the area of a bolt hole in the cover of the container was discovered. A water sample obtained from with4.n the container indicated 600 ppb soluble silver (from the control rods) and negligible A1. Visual inspection of the interior of the container and its cantats using binoculars disclosed no unusual conditions. It was concluds fm an evaluation of data obtained that the intermittent gas discha-ge was the result of rad 4.olitic decomposition of the water in the gLI k

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container. This condition will be eliminated during shipment of the spent control rods since the water will be drained from the container prior to shipment.

At the beginning of the period the renaining Core I control rod was placed in a shipping can and stored in the spent fuel pit. This control rod will be examined off site at a future dato under an A.E.C.

contract. The stainless steel can has been designed for wet shipment of the rod and since it is pressure tight, has a safety valve incorporated in it.

Upon discovery of the gas formation in the aluminum container, a pressure gage was attached to the s4ngle rod can. By the end of the period, the internal pressure had increased to approx 4.mately $ psig, still considerably below the safety valve relieving pressure of 20 psig.

During February, the first of fourteen Core I fuel assemblies

,n, was shipped for inspection and examination off site under an A.E.C. contract.

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Before loading the assembly in the cask, a " dry-run" was conducted to check out the procedure to be followed in the " hot" loading. The spent asembly was placed in the cask on Februar 26, and following decontamination

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and imoection of the cask, it was placed on a trailer and left the site on Febr0ary 27.

Nine fuel assemblies for use in Core III were delivered to the plant during the period. A total of 36 new feel assemblies are now in m(,)

storage at the site.

No reactor scrams or plant shutdowns occurred during February.

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Ma4ntenance Following is a sumnary of major activities carri9d out by plant maintenance personnel during February.

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1.

Installed a te.porary sample point on the pressurizer vent for steam phase sampling of the pressurizer.

2.

Repacked No. 3 charging pump.

3.

Removed closure bolts and cover from aluminum contol rod shipping container for investigation of gas formation within the container. Following tre investigation the cover was replaced but not bolted d wn.

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Installed a pressure gage on the stainless steel, single control rod can.

$. Started installing insulation in tha spent fuel pit building.

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- 6. Replaced a ruptured rubber expansion joint in the suction of No. 1 condensato pump.

7.

Installed check valves in the condensate pump gland seal-water lines t6 prevent overpressurizing the seal water system.

8.

Cleaned No. '1 Jacking pump solenoid valve and installed new coils.

9.. Installed a slight glass in the leak off line from-No. 3 charging pump.

10 Replaced a dsfective lightening arrestor on the 2.h KV.

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Installed a metering orifice in the spent fuel pit purifi-cation line and a 0-100 gpm flowmeter.

12. Replaced the mercury cell on the narrow range pressurizer level recorder. The former battery had leaked causing a ground on the level signal.

O ce 9 etea the 471 8 er the re1er1ex ee187= +=dteetere-1 13.

Each flux wire drive new has its own posi?im indicator.

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Inteichan@dthe transmitters ani main control board gages on initial pmssure regulator pressure ani load 3imit pressure. The load limit and governor pressure rages on -

the main control board now have the same range n4 king comparison easier.

O Chemistry At the beginning.of the period the main coolant remained in a borated condition (~h00 ppm). Additions of demineralized make up water-to the primary system on February 6 and %, resulted in diluting the boron concentration to 360 ppm and 3h2. ppm mapectively. On February 15,' boron removal was initiated and by February 18, the main coolant boron concen-tration had been' reduced to less than 1 ppm..

Intermittent high dissolved oxygen levels were noted in the main coolant during the period. A considerable effort was dimeted to inves-tigating A oxygen situation during the per4 od and a description of the investigation follows.

l Main Coolant Dissolved oxygen Investigation

~ Main coolant dissolved oxygen concentration is normally measured once per day.. The normalresult of this analysis is a main coolant-oxygen concentration varying.between negative and $ ppb. On several occastor E :

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-h-g fo11owing a deborat<on after a cold shutdown and during the first boron.

test at power,' dissolved oxygen concentrations of up to 300 ppb had been-observed.

On the day following the start of the second boron test at power, measured oxygen levels between h0 and 210 ppb were noted. During the.next four days normal concentrations were found,(negative to 5 ppb.) Values up to 200 ppb were observed at times during the second week of the boran test; however, these values rapidly decreased to negative within one to two hours.

It was also noted that the highest oxygen concentrations were detected immediately after pres'surizer level cycling. (The pressurizer is intentionally.

cycled with a borated main coolant system as'well as during boration and 4

de-boration to maintain uniform boron distribution in the main coolant system.

1 Under normal operating conditions, the' pressurizer leve1 is not cycled.)

On February 1h, a series of oxygen analyses were 'perfomed concurrent with

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pressurizer cycling and a maximum oxygen concentration of.3700 ppb was ob-served.

In order to pursue the oxygen investigation, boron was removed from the main coolant system starting on February 15. Since the appearance of l

measurable oxygen concentrations was intermittent and appeared to be related to pressurizer cycling, the investigation centered about intentional pressur-4zer cycling ace ompanied by main coolant oxygen analyses.

The.t sating confirmed that oxygen levels did increase following cycling.and tha t the concentration diminished rapidly thereafter. Further-more, as testing continued beyond the first two days, the measured peak-oxygen concentratun following a surge was successive 1y smaller as indicated below Max. 02 Concentration Fol1owing Surge 4

O February 18 16* ppb

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February 19-3h0 ppb February 20 80 ppb 4

On February 20, samples were also obtained from the vapor space in the pressuriser. ~ After removing. the condensible gases, the 02 content of the non-condensible gases amounted to betweep 0.2 and 3.M.' On February 21, the pmssurizer solenoid relief valve was opened allowing discharge from the pressurizer vapor space to the low pressure surge tank. Vapor space sampling

- for oxygen from this point through the end of the month indicated 0.1 to 0.2%

0 in the non-condensible gas'with the exception of one test which indicated 2

1% 0. The main ecclant oxygen concentration during the same period stab-:

2 ilized at 5-10 ppb following surging of the pressurizer.

I During the course of the testing, pressurizer cycling was accom-plished by varying the main coolant, liquid volume with the charging pumps and also thermally.,Various pressurizer heater combinations were also

- O emn1ered hut no corre1ation hetween ex18en 1 eve 1 end methed of sur81ns or heater combination _was evident.

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-5 gO Reviewing the results It was apparent that oxygen hau

'ilated in or had been produced in the pressurizer. Only by agitating the _iqaid in the pressurizer through cycling were significant oxygen levels found in the main ecolant and then only for relatively brief periods of time. The presence of boric ac4d in the main coolant or in the pressurizer is e. possible contributor to the oxygen problem. In the test work to date no other contri-but6rs stand out as possibilities.

Regardle.1s of the mechanism by which oxygen accumulates in the pressurizer, it would appear advisable to provide a controlled gas vent from the pressurizer vapor space to the low pressure surge tank. Since September 1962, when various pressurl:cr valves were reconditioned, no leakage path for non-condensible gases in the vapor spac.e of the vessel has existed. It is felt that a suitable vent will provide n desirable degree

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of control over the accumulation of any non-condensible gases in this location.

v Reactor Plant Perfornance The following were determined by means of in-core instrumentation measurements at a power level of h85 MWt, control rod groups 1, 3, h, 5 and 6 at 88 7/8 inches and group 2 at 66 0/8 inches with h00 ppm boron in the main roolant system:

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F 30

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Moderator temperature coefficient data measured at peak xenon conditions during Core TI shutdowns are tabulated belows (n)

Shutdown No. 52-2-h (11-h-62) dF

(-2.h3 + 0.0h) x 10~b d (O

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System Conditicas:

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= 513.3 F avg.

Xe poisoning = ~ 3.7%d /0 928 MWD /MTU Cora II Avg. Burnup

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Grps. 6, h, 2 @ 90 inches Control Rod Positions

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Grp.,3 @ 37 7/8 inches o

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V Shutdown No. 53-2-5 (1-lh-63)

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(-2.2 + 0.1) x 10 d(O d t'

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dT oF System Conditions: T

= $12.5 F avg.

Xe poisoning = u 3.5% df 2718 WD/MTU Core II Avg. Bernup

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Control Rod Post.tions = Grps. 6, h, 2 @ 90 inches orp. 3 @ 67 7/8 inches

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A comparable measurement on Core I indicated:

(-2.0 + 0.2) x 10-b d(O dP

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$1h F System Conditions: T

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1h75 WD/MTU Core I Avg. Burnup

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Control Rod Positions = Grps. 6, 3, 1 @ 90 inches Orp, h @ 2h 0/8 inches Core reactivity behavior before, during and after the boron test is discussed in the "SPECIAL TESTS" section of this report.

Turbine Plant Performanca Preparations were made during February for further analysis of the main steam line vibration. Pressure taps will be installed in selected locations along the steam lines to assist in identifying the source of the vibration.

Secondary plant performance dam were acquired when No.1 feedwater heater was removed from service to permit repair of a leak in the heater vent line.

A reduction of 1.6% in plant thermal efficiency occurred as a result of bypassing the heater.

Based on refined calorimetric techniques, the total MHWt output of Core I was zucalculated during the period. The revised output is approx-imately 2% higher than previously determined and is primarily the result of

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corrections..to periods of operation at gross generator outputs below 100We.

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~O Health and Safety Liquid ' waste with a total activity of 0.09 millicuries was dis-charged from the plant during February. Gaseous waste containing 3.62 curies was discharged during the same period. Six drums of solid waste.

j containing approximately 9.8 millicuries were prepared while no solid waste was shipped. The concentration of waste products discharged from the plant was at all times well below the maximun permissible.

i Twelve packages of main coolant liquid and crud samples containing approximately 6 millicuries were shipped for off site analysis.

1 During the period the steam generator blowdown tink was flushed and drained to the waste disposal tanks. The"maximun radiat4.on level on contact before drainage was 30 mr/hr at-the bottom of the blowdown tank.

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Immediately after drainage it was 3 mr/hr and 15 mr/hr one day later,

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Radiation levels measured at a distance of 1 cm. from the open top i

.of a 500 cc cylinder of condensed vapor from the pressurizer were 15 mr/hr 4

gamma and 30 mr/hr beta.

c During February, spent fuel assembly A-25 was loaded'in a cask and shipped off site for examination. General radiation and contamination

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or the are=t r e1 vit vr+er to 1o a4"s "ere 5 to 15 r/wr and1,000toh,000dpm/ft. respect 4.vely. No increase in either radiation cr contamination was noted in the immediate area during transfer of the cask

~i from the spent fuel pit to the decontamination pad.

4 levels of 2,000 to 15,000 dpm/ft.gd been placed on the decontamination pad After the loaded cask h i

were measured on the sides and 1.6 x 10o dpm/ft.2 on the bottom of the cas levels were reduced to '100 to 1,000 dpm/f t.g. Following decontamination,2 on the' sides and 700 dpm/f t.

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on the bottom.

i The radiation level on the spent fuel cask, loaded and ready for shipmentwas2.0mr/hn, maximum,'oncontact.

Personnel exposures for Yankee plant personnel as measured by.

film badges for the month of January 1963, indicated 182 mr (average exposure) and 900 mr (maximum individual exposure).

Continuous monitoring of off site airborne activity,during 7ebru-ary indicated levels consistent with pre-operational values.

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l-A routine. radiation survey during the period resulted in the following general area and contact radiation neasurements:

t Waste Disposal Building Gas Stripper Cubicle 20mr/hr General area

. 0as Stripper 50mr/hr Contact Evaporator Cubicle lhar/hr General area Evaporator h5-100mr/hr Contact Incinerator Pit 5-10mr/hr General area Incinerator Ash Funnel 150mr/hr Contact I

' Primary Auxiliary Building i;

charging Pump Cubicles 1-20 mr/hr General area l

Charging Line (Suction) h0-50mr/hr Contact Purific tion Pump Cubicles 10-h0mr/hr General area L

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Purification Pump Tailpipes 500-600mr/hr Contact Shutdown _ Cooling Pump Cubicle 5-15mr/hr General area Tailpipe Discharge Side of S.C. Pump 250mr/hr Contact Valve Room-MC Dieed Line 650mr/hr (Max.) Contact Low Pressure Surge Tank Cubicle 150 mr/hr.

Entrance Plant Operations O

ist eaed 1 rr er P t Per ste= t t< t4== rer the 1

month of February 1963, and a plot of daily average plant load for the same period.-

Special Tests Core II Operation at Power with Boron Shim Control O

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The boron shim control test on Core II was performed to demon-strate the use of soluble boric acid in the primary coolant as a supple-mentary control method while operating the reactor at power. The test wa-conducted to verify the feasibility of using supplementary boric ac'd control as a means of extending the lifetime and reducing power costs for I

pressurized water reactor cores in general and specifically, as a proof.

test for the mode of operation planned for Yankee Core III operation.

The design of Core IIT requires the use of boric acid for supplementary reactivity control to replace xenon poisoning during early core operation at power. This requires the use of about LOO ppm of boron in the primary coolant at power until equilibrium xenon poisoning is I

established.~ This design criteria was established for Core III as a l

reasonable extension of the_ Core I and Core II operati.on which used boron for supplementary reactivity cons /1 during periods of operation at low power and reduced coolant tanperatares.

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2.0 Baclotround Tnformation Yankee rou.tinely obtains and analyses detailed core reactivity data to evaluate the observed core behavior and analytical techniques for predicting core behavior. These analyses have shown excellent agreement over long term periods of several weeks; however, during short term intervals, slow reactivity transients have been observed which are difficult to explMn using the usual simp 14fied reactivity models. Such reactivity transients have been observed during Core I and Core II operation in conjuction with a change in reactor power level (including hot shutdowns) or reactor power distribution and have occurred slowly over several days with magnitudes up to approximately 0.h % dP. These transients are believed to be the result of one or a combination of the following:

1.

Changes in the heat transfer properties of the UO2 pellets p

or th'e pellet to clad gap with a resultant change in fuel V

temperature and doppler coefficient losses.

2.

Changes in reactivity importance weighting of fission pro-ducts or fissionable materials due to redistribution within the fuel rods.

3.

Fission product transients for materials (other than Ie-135 and Sm-lh9) which are not treated explicitly in h3 the analytical calculations.

It seems likely that. transients of this nature can superimpose their effects on any boric acid test, since control rod position and I

therefore, power di.stribution are changed substantially as boric acid I

is added or removed.

In addition to the transients described above, wh4ch occur l O e1e 17 ever ever 1 aer, the 91 et a e aemo tretea e reeet+vit7 ver4 tie =

resulting from changes in the chemistry of the primary coolant. Testa conducted in March 1962 and again in December 1962 indicated that an increase in the pH of the primary coolant associated with the presence of ammonium hydroxide resulted in a gradual increase in core reactivity of day.hpto0.h%69wh4.choccurredoveraperiodofaboutonehalf 0.3%

Following restoration of the normal neutral primary coolant chemistry, the core reactivity gradually returned to normal over a period of several days. This reactivity increase is believed to have resulted from one or a combination of the followings 1.

Removal of a neutron absorbing material such as boron or l

control rod corrosion products from the surfaces of the fuel rod due

.,o the increase in pr4 mary coolant pH and the resulting decrease in neutron absorption in the core.

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Change in heat transfer propert'es of crud deposited on the surfaces of the fuel rod due to the increase in primary coolant pH resulting in decreased fuel temperatures and doppler coefficient losses.

.The detpi).ed results of tests performed to determine core reactivity behavior during primary coolant chemistry changes are reported in the Yankee Nuclear Power Station Operation Report No.15 for March 1962 and Operation Report No. 2h for December 1962 During the operation of Core I, a test was performed using supplem'entary boric acid shim control at power which demonstrated the abil-ity of the plant to operate in that manner. During this test, the boron was increased from 0 to about h00 ppm. The plant operated at h00 to 300 ppm for one week, following which the boron concentration was reduced from 300 to O ppm using normal plant controls and procedures. Operation of the (d_')

plant throughout this test was normal and all control systems. functioned very satisfactorily. The maximum rate of change of reactivity during the test occurred when major boron concentration changes were effected in the primary coolant system and were lower than those encountered during normal operat'onal xenon poisoning transients. An unexplained long term reactivity transient occurred auch that the possibility of gradual hideout of boron in the core could not be positively ruled out. The test was reported in detail in the Append 4x of Yankee Nuclear Power Station Operation Report No.10 r~N for October 1961.

V 30 Summary of Core IT Boron Shim Control Test The reactor power level was zuduced from $h0 Elt to h85 MWt on January 9,1963, in order to stab 4.lize plant conditions prior to conducting the boron shim control test. Steady state operation was inter-rupted by plant shutdowns on January 1h,1963, and January l$,1963, for o

maintenance work on primary valves which resulted in a disturbance of core V

reactivity conditions with an unexplained reactivity loss of approximately 0.2% d p This core reactivity disturbance had not stabilized when approval was received from the USAEC on January 2h, 1963, for performance of the test.

On January 28, 1963, core reactivity was considered to be suf-ficiently stabilized to begin the test and boric acid was added to the primary coolant using normal plant. equipment to achieve a boron concentration of h00 ppm. Boration was accomplished by cor.tinuous operation of eno charg-ing pump at minimum flow rate with pump suction alternated between the concentrated boric acid storage tank (for 5 minutes) and the safety injection storage tank (for 10 minutes). This resulted in a maximum boration rate o' about 600 ppm / hour and an average boration rate of about 200 ppm / hour.

about 2 x 10~ gen rate corresponded to a rate of change of reactivity of average borat d9 and was by far the highest experienced during the minute 7V test. The performance of plant controls and instruments was very satisfactory, resulting 4.n a smoothly accomplished boration.

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kj During tne boration cycle, a second charging pump was operated near full flow while taking suction from the Low Pressure Surge Tank to provide borop mixing in that tank. The boron concentration in the pressurizer was maintained near equi 14brium with the primary coolant by periodically cycling the piessurize water level to 10 inches above and below the normal level of 120 inches. These operations resulted in main-taining quite uniform boron concentrations in the prinary coolant and in all auxiliary systems. In order to maintain a constant boron concentration 4n the primary coolant for as long as possible, the Low Pressure Surge Tank (LPST) was initially filled to a level about 10 inches above its normal control point. No makeup was added to the primary system until the LPST level had fallen about 10 inches below its normal control point. At this point, mkeup was added mnually using unborated demineralized water supplied through an integrating meter. This allowed a precise calculation of the expected boron concentration after makeup, for use in core reactivity balances.

(V7 During the test, it was necessary to make up to the LPST on 2/6/63 and again on2/13/6?. The calculated boron concentration following mkeup agreed very well with the boron concentration determined by chemical analysis of the primary coolant.

Dr. ring the boron test period, there was no bypass primary coolant purification and only part tire feed and bleed. Purification was terminated on 1/16/63; a six to ten hour feed and bleed schedule commencedon1/22/63. In the interim time until the 1/28/63 boration, p)

MC chemistry stabilized; in particular, no oxygen was observed with diis

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mode of operation.

The accompanying data presents the status of major chemical and radiochemical values before, during and after boration. It should be noted that more detailed infornation will be available when samples collected by Westinghouse APD ara spectrographically analyzel.

/%Q The main coolant system pH was consistently measured as 6.h, wh4ch is about 0.8 pH units higher than might be expected. The sodium-2h nuclide was 4 dent 4f4ed in the main coolant and a preliminary Westinghouse AFD result indicated a 0.3 ppm sodium concentrati.on in the primary water. This sodium concentration results from an impurity in the boric acid and lack of cation removal. In addition, it is believed that the system was borated a sufficient length of time to build up a small concentration of B-10 (n -4) lithium. Ammonia determination with borated water requires the use of distillation apparatus; this equipment is not available at the site and Westinghouse AFD agreed to run the tests on their samples. Qualitative tests indicated that if anmonia concentrations did exist, it did not exceed tenths of ppm levels.

The reactor power level was reduced to 2h0 IEt (75 IMe gross) for a few hours on 2/3/63, due to a scheduled outage of one high voltage distribution line to the plant for electrical maintenance.

h' On 2/15/63, boron removal from the main coolant system was initiated in preparation for establishment of normal main coolant i

. m(d purif* cat *on and chemistry test 4ng associated with the detect 4.on of s'g-n'f4 c' ant oxygen in the mat.n coolant. Boron removal was accomplished snoothly using normal plant equipment and normal plant boron removal procedures. The boron concentration was reduced to less than 20 ppm in less than 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after the beginning of dilution. The reactor power level was maintained at h85 Kdt until 2/28/63 to continue the study of core reactivity effects. At that time reactor power level was returned to the licensed value of 5h0 Kdt.

The core reactivity behavior observed during this test period is presented graphically in the acconpanying figure. The plot of unexplained reactivity versus time represents the total of all observed core reactivity effects which cannot be related to known core ree.ctivity influences from change in coolant temperature, coolant pressure, coolant boron concentration, control rod position, reactor power level, xenon p

poisoning, or core barnup. The unexplained reactivity plot was normalized U

to 0.0% at the time of 4nitiation of boration on 1/28/63. Following initial boration to h00 ppm, the core experienced an unexplained reactivity loss of about 0.1% d/O whi?h occurred in one day. Thi s was.

followed by an unexplained increase in core reactivity of about 0.55% 6t0 which occurred uniformly over a nine day period. During the following seven days of operation at high boron concentrations, there was no change in the unexplained core reactivity indicating that the plant wac undergoing normal reactivity depletion due to power operation.

During boron dilution on 2/15/63, there wts an unexplained react *vity loss of about 0.7% 8 9 which occurred unt.formly over a two and one-half day interval. This unexplained loss remained for a period of about five days after boron removal and then some of the loss was regained as the core operated for a period with abnormally low reactivity depletion due to burnup, h.0 Summary and Conclusions The Yankee plant has operated very satisfactorily at power with boric acid dissolved in the primary coolant fcr supplementary shim control.

Two separate boron shim control tests have been performed to demonstrate the practicability of such operation, one durmg Core I operation and one during Core II operation. The general conditions and results of these two tests are summarized below:

4 Plant Conditions Core I Test Core TI Test Duration of power operation 7 days 18 days with boron Boron concentration (ppm) 3}0 to 320 h00 to 3h0 Average Core Power (MWt) 380 h85 d

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Plant Conditions Core I Test Core II Test Heat Flux in Average Channel 81,500 108,000 (BTU /HR-SQ.FT.)

4 Heat Flux in Maximum Channel 200,000 200,000 l

- (BTU /HR-SQ.FT. ) '

Maximum Heat Flux in Core 295,000 290,000 (BTU /HR-SQ.FT.)

l Temperature Rise in 28.h 36.2 Average Channel (OF)

Temperature Rise in Maximum 85 83 Channel (OF)

O Average Core Burnup (MWD /MTU) h250 3h50 Primary Coolant Purification Cation Resin None Duration of Primary Coolant 32 HRS / DAY 8 HRS / DAY Feed & Bleed Operation Primary Coolant pH 6.1 6.h Unexplained Reactivity About 0.6%

About 0.5%

Behavior after Boron Addition d p Loss Og Gain Unexplained Reactivity About 0.h%

About 0.7%

after Boron Removal 69 Gain 6pIosa C) 1,com,1usio,, the method of supp1ementa,y bo,o,,h,,,co,t,,1 planned for Core III operation has been tested and shown to result in satisfactory plant performance. The following specific conclusions can be made:

1.

Present plant systems and controls are more than adequate for contemplated Core III operation. The reactivity control sybms operated smo,,,,aly and effectively at all times during the test. Control requirements for reactivity i

insertion and removal rates were great,est during baron

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addition and dilution phases. While the reactivity changes l

during boron additien'and removal were relatively slow, they were three or foul times greater than those expected during normal operation on Core III. The plant systems have been shown to be capable of achieving and maintaining l_

N prescribed boron concentrations. Primary coolant temperature i

p eni pressure controls and indication all functioned well.

3 The secondary plant performance was unaffected by this mode l-of operation.

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Primary coolant chemistry conditions were acceptable for Core III operation. No significant increase in plant radioactivity levels were observed as a result of operation with the borated coolant. Primary coolant activity and crud levels were not significantly affected by the test.

Oxygen was observed for short periods in the coolant following pressurizer cycling, but was rapidly consumed by recombination with the excess hydrogen in the prima 7 coolant. Further testing is in progress to ascertain

.whether or not oxygen is directly associated with boric acid or is caused independently by other plant operation.

3.

The unexplained reactivity variations observed during the test are accepttble for Core III operation. Reactivity variations such as those experienced during the test were of such small amounts and occurred at such slow rates that hs they represent no operating problem. Large plant load chang.3s and large, boron concentration changes have been shown to result only in very slow changes in unexplained reactivity behavior. Core reactivity conditions observed prior to boron shim operation were duplicated following such operation indicating that no permanent reactivity' effects occur as a result of operating with large quantities of boron in the primary coolant at power. The unexplained

(#)

reactivity trend which occurred during the second boron shim operation at power were observed to terminate after about ten days and subsequent operation followed expected reactivity behavior indicating that probably very long term l)ron shim operation could be achieved without complication.

h.

Unlike the Core I test the Core II boron test gives no

(')

indication of the possibility of boron hideout during the U

test. If anything, the results are more s4m41ar to earlier high pH tests during which reactivity had been shown to increase gradually.

5. Considering the results of both boron tests and high pH tests the only general conclusion possible at this time seems to be that within rather narrow limits the reactivity of the Yankee core is affected over periods of time by the particular water chemistry existirg.

Ob

1TSTRY DATA - h CORE TT BORO. h 3T

( )

MAIN COOLANT FERIOD I PERTOD II PERIOD TIT FERTOD IV 1/9/63 to 1/16/63 1/16/63 to J,./28/63 1/28/63 to 2/1$/63 2/15/63 to 3/1/63 Continuous 25 gpm 1/16-Purif4 cati on System 13 orated Cont 4nuous 25 dpm feed and bleod Terminated Continuous Feed and bleed on feed and biced 25 gpm feed and bleed 25gpm6to10hr/ day Continuous 30 apm Cont 4nuous 30 gpm No purification Purification Purification 1/22-Feed and bleed on 2/15-System deborated 25 gpm 6 to 10 hr/ day Uo Purification Grosa Sp Act mc/ml 1.2 x 10~1 1.h x 10~1 1.7 x 10~1 7.5 x 10'

.I-131

' 2.9 x 10-3 n:/ml 2.6 x 10-3 h.$ x 10-2 2.2 x 10-2 Crud level o,1g o,1g o,17 o,lo Ppm 2

neg to $

neg to $

neg to 3700 1600 to neg Diesolved 0 ppb D4ssolvedsilveg 4 10 4 10 4 10 4 10

& nickel ppb _t__

Crud Analyses dpm/rg Date Date Date Date 1/9/63 1/16/63 1/21/63 1/28/63 1/29/63 2/h/63 2/26/63 0

0 0

6 6

6 6

C7 $1 7.5 x 10 6.7 x 10 9.0 x 10 8.8 x 10 6.0 x 10 11.7 x 10 h.6 x 10 5

5 b

5

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6 6

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6 6

6 6

6 6

6.1 x 10 6.0 x 10 3.5 x 10 3.0 x 10 5.8 x 10 2.h x 10 Fe-$9 6.7 x 10 Co 60

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,h.$ 'x 105 h.h x 105 5

5 y

Ag-110m 8.1 x 10 6.8 x 10b 1.$ x 105 9.8 x 10b h.$ x 10b 5

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O O

O O

O YANKEE ATOMIC EIECTRIC COMPANI - OPERATING

SUMMARY

FEBRUARY 1963 EIZC1RICAL MONTH YEAR TO DATE Gross Generation KWH 102,50h,500 215,020,500 1,916,h92,500 Sta. Service (While Gen. Incl. Losses)

KWH 6,58h,800 13,728,30h 1hh,h6h,871 Net Generation KWH 95,919,700 201,292,196 1,772,00/,629 Station Service 6.h2 6.38 7.5h Sta. Service (While Not Gen. Incl. Losses)

KWH O

185,138 1h,153,976 Ave. Gen. For Month (672 HRS.)

KW 152,536 Ave. Gen. Running (672 HRS.)

KW 152,536 FIANT PERFORMANCE Net Plant Efficiency 29.h0 29.h1 Net Plant Heat Rate Btu /KWH 11,608 11,60h Ibs. Steam / Wet KWH 13.77 13.82 Circulating Water Inlet Temp.

Maximum F

37 0F 33 le n1=ri

.02-Plant Operating Factor 89.89 89.51 65 NUCIEAR MONTH CORE II TO DATE t

Times Critical 0

29 291 Hours Critical HRS.

672 3900.3h 17,1h7.77 Times Scransmed 0

3 33 Equivalent Reactor Hours @ Sh0 MWt HRS 60h.1 3h78.7 11,395.8 Average Burnup of Core MWD /ttU 653.5 3763.1 Control Rod Position at Month End Equilibrium at

$h0 MWt, $13 F (T avg.)

Group 1 Rods out-inches 887/8 Group 2 0

Group 3 88 7/d g

Group h 887/8

?

Group 5 715/8 Group 6 88 7/8 1

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