ML19351E190

Operation Rept 72 for Dec 1966

ML19351E190
Person / Time
Site:	Yankee Rowe
Issue date:	01/25/1967
From:	YANKEE ATOMIC ELECTRIC CO.
To:
Shared Package
ML19351E189	List: ML19351E188 ML19351E190
References
NUDOCS 8011260118
Download: ML19351E190 (9)

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[ NORMA Q YANKEE NUCLEAR FCWER STATION Filo copy OPS 1ATION REPORT NO. 72 For the month of DECH4 bht,1966 O

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Submit,ted by YANKEE ATOMt

._V;TRIC COMPAN,Y _

Boston Massachus gE January 25,196 /[

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p,' q 2-This report covers the operation of the Yankee Atomic Electric Company plant at Rowe, Massachusetts, for the montn of Decemoer 1966.

et the beginning of the period tne plant was operating at approx-im:tely 18h Mie. This was gradually increased to 186 M4e as circulating water temperature decreased fron h50F to approximately h00F. As 3 result of the increase in primary to secondary learage at sn e<ponential rate (3h gpd to $20 gpd from December 1 to December 22) tr.e de:1; ion was made to isolate the suspect No. h steam generator.

At 2130 hours0.0247 days <br />0.592 hours <br />0.00352 weeks <br />8.10465e-4 months <br />, Decenner 22, reduction in plant load to h50 NWt (139 MWe) was initiated; h30 NRt being the maximam permissible power during three loop operation. By 2200 hours0.0255 days <br />0.611 hours <br />0.00364 weeks <br />8.371e-4 months <br /> no. h loop isolation was completed.

The loop was initially msintsined at operatt.g temoerature and p-essure while an attempt was made to determine the laak rate of the isolated steam generator. This determination wr 2 unsuccessful in that the secondary side boron concentration increased f on 77 ppm to approximately 12hD ppm indi-cating the posrible occurrence of chemical hideout and channeling of leakage water directly to the blowdown line. By the end of the month tne calculated y

primary to secondary leakage of the operating loops was approximately 20 gpd, ccmparable to the rates encountared prior to the Core V-V1 refueling shutdown.

At 1505 hours0.0174 days <br />0.418 hours <br />0.00249 weeks <br />5.726525e-4 months <br />, on Decemoer 2h, the reactor sc rammad. Turbine Trip and Rod Drop memory lights were displayed. However, plant process instrumen-tation indicated that these were a consequence of the sc sm rather than the causative factors.

Pressurizer paessure and level cecreased simultaneously at the moment of the ceram as did the flux Jevels en both uncorepensated ion chnmbers being monitored on the recorder. No flux tilt was observed as would 7,

be expected as a result of a decpped rod. The scram was considered to be of a spurious nature. 3y 1"$7 hours, the reactor had been taken e-itical and the turbine phnsed on the line, At 18h5 hours plant load was approximately 1M We.

This load wao maintained until 0650 hours0.00752 days <br />0.181 hours <br />0.00107 weeks <br />2.47325e-4 months <br />, Dweriber 25, at which time load was increased to 139 M4e.

Centrol rod exereires were conducted on Decenber 28 furnishing further assurance of prcper control rod operation, position and position indic. tion. During the condcet of the exercise it was spec:.fically netwf

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that rod moverent csured a flax charge on at lesst one of the urcompersated

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ton che.mber chsnnels.

On Decenter 29, centrol rod groups B, C ; and D ware banked at 87 3/8" as the seccnd step of the Core VI m ximum withdrawal linitation program for distribution of guide block wear.

At 2132 hours0.0247 days <br />0.592 hours <br />0.00353 weeks <br />8.11226e-4 months <br />, on Decer.ber 28, tha reac tor again scrammed with the following memory lights dispicyed: Lov F rerscrizer Presstra. Lew Flow, Turbine Trip and Red Drop. Inspection of plant process ins trunentation once more revesled no abnormal conditions prior to the scram.

Pressurizer pressure was normal. The subsequent drop of pressurizer pressure and level was indica-tive of another spurious reactor scram. Investigaticn and analycis of the previous spurious scran en December 2h. hcd lead us to the belief that the loss of Flow scram circuit could be suspect. The circuit was then operating in the two-cut-of-four loop scram logic mode and consequently in the '! half-fired" state with No. h 1 cop isolated.

Inasmuch as tre plant had not previously teen operated on three Icops for ary extenced perico of time in the past, it was highly probable that this circuit was permitting currer;t leakage to the

.. scrcm bistsble magnetic amplifiers and ccnsequently causing spurious scrams.

Prior to resctor startup on Decenter 28, the Loss of Flow scram circuit was returned to the one-out-of-four loop scram logic mode and a test signal for j

the isolated No. h loop inserted to simulate nornal conditions. The initia-tien of a scram by loss of flow on any one of the operating loops v s veri-fled. By 2339 hours0.0271 days <br />0.65 hours <br />0.00387 weeks <br />8.899895e-4 months <br />, December 28, criticality was achieved and the turbine thsned on the line. At 0815 hours0.00943 days <br />0.226 hours <br />0.00135 weeks <br />3.101075e-4 months <br />, December 29, plant losd was approximately 139 MWe.

One shipment of spent fuel was made during the month of Decemoer.

On the sixth the spent fuel shipping cask was loaded with ten elements and the cask shipped on December 9 This shipment is the sixteenth in the series of spent fuel shipments, bringing the number of elenents shipped in the ten element ccsk to 156 and the total number of elenents shipped to date to 172.

The vapor centainer peretration leakage testing program centinued into this reporting period. Included in the penetrations successfully tested during the perici were the vapor container heatirg cystem and the valve sten le-k-off system. The vapor contciner air leakage rate was normal throughcut the neriod.

Plant Shutdowns ShutdcEn No. 86-6-1 12/2h/66 A 2.88 hour0.00102 days <br />0.0244 hours <br />1.455026e-4 weeks <br />3.3484e-5 months <br /> shutdown resulting frem a reactor neram.

Scrsm No. 53-6-1 22/2h/66 A spuricus reactor scram from a newer level of h50 M4t.

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Shutdtwn Nc. 87-6-2 12c28'66 A 2.12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> shutd wn resulting fron a reactor scram.

Scr m Nc Sh-6-2 12/26/66 A spurious reactor scram from v power level of h50 MWt.

l'isnt Fbi ntent.nce

,,( 'j The following ic a list of the major plant naintenance items per-formed by the pl;nt staff daring the month of December,1966:

1.

A small circulating water cunp was installed on the cooling water jacket of Nc.1 cont"ol air ccmpressor to maintain the jceket at an even temperature and prolong the life of the carbon pistor rings.

2.

The installation of a cross connection between the potable water supply ord the service wuter mani fold on the tu-blne ;ir coolers wss completed. This inst 311ation will n Ecw cooling of the turbine oil during turbine co.sstd;wn in the event that se"vice water pumos,rc unav-il able.

3.

Strainc-barkets were fab-icated for use in improving tne tear.

"ng wate-fi:tering system for tha -i rcula ting w.ter pumps, b.

Insuintion -2reved : rom the bleed : team lines during the Core V-VI refueling shutdown w 2n re pl,ced.

b No. 2 boiler feed pump was repacked.

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A lenk in the gas syctem of No.1 statirn service transformer

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was repaired.

7 Fabrica. tion of a new af terecoler for No. 2 control air compres-sor was started.

Instrumentation and Control The follewing is a list of the major instrument, Lion and centrol m4iatenance items performed ty the plant staff during the m3 nth of December, 1966:

1.

T'r.e main coolant pressure channel calibration vna checked.

2.

The leskage resistance and sensitivity of the apare BF3 detector wss determined.

3.

A defective te2cflex drive relay was replaced.

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Vibration tests of the circulating water pumps were conducted.

5 Repair of the control room net output indicator was completed.

Reactor Flsnt Performance Core reactivity depletion prior to three loop operation was normal at approxir.stely 0.8% A K/K per 1000 M4tD/MTU.

As a result of the large boren went ration swings in the main coolant system subsecuent to three loop oper-swion, calculations of reactivity depletion have not yielded consistent results.

The report of the Core V-VI refueling, component inspection has been comp:eted in draft form for issue next month.

The following usrameterc were determined by means of in: ore instru-("';

rentation at 6C0 M4t, $26.9o? Tsvg,1255 ppm boron c.r.d control rod groups P,C and D at 87 and group A st 821/8:

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^ v 1.?" : Outlet Temperatur?

Mecondary Flant Perforn,nce Feedw-ter hester termin 1 difference at 165 Mde,1.6$" Hg back-precaure, 5270F Tnyg:

1. 1 - 7.60F

1. 2 - 16.60F

1. 3 - 16.00F Cerdencer termin'l differeree:

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-h-Chemist q At the beginning of the period, the primary to secondary leak rate was increasing exponentially. Oross activity levels of steam generator water indicated that the major leakage was occurring in the No. h steam generator.

On December 22,1%6, No. h loop was isolated from the main coolant system; at this time, the estimated primary to secondary leak rate was $20 gpd. After the No. h loop was isolated an attempt was made to ascertain the leak rate in the steam generator while operating temperature and pressure were maintained.

The determination was unsuccessful in that the data indicated an increase in the steam generator water boron concentration from 77 ppm to 12h0 ppm. This data in conjunction with erratic phosphate and tritium information indicated a possible hideot t condition and a channeling of leakage water directly to the blowdown line. The primary to secondary leak rate evaluation will be continued with the No. h loop isolated.

Initial data at the end of this re-port period indicates a substantial reduction in the 3eak rate of the operat-ing main coolant system. However, equilibrium conditions have not been attained.

The main coolant boron concentration had decreased from 1363 ppm to o

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1287 ppm by December 22.

Following No. h loop isolation, the boron concen-tration varied between 1287 ppm and 1395 ppm. This erratic performance was due to leaPage of main coolant into the more concentrated borated water in the No. L toop.

The bleed of h*c. h luep water, to maintain reduced loop pressure,.'nto the low pressure surge tank resulted in erratic coolant boron concentrations.

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The average main coolant iodine-131 concentration was 1.6 x 10-5

\\ J uc/ml and the I-131/I-133 atomic ratio was 0.77 The average system crud level was 0.26 ppm. Following the control rod exercises on December 28, the crud level increased to 0.7h ppm. Silver-110M was detected in the coolant crud for the first time since Core III operation.

A main coolant crud sample on December 5 had the following radio-f.l chemical analysis: dpm/mg crud.

Cr-51 h.h x 10 Fe-$9 1.6 x 106 6

6 Hf-181 3.8 x 105 Co-58 6.0 x 10 6

6 Mn-$h 1.1 x 10 Co-60 2.0 x 10 b

Ag-110m 2.0 x 10 A main coolant gas sample on December 21 had the following radio-chemical analysis:

ue/cc gas:

Xe-133 7.6 x 10-3 Xe-135 9 5 x 10-3 A-bl 1.8 x 10~1

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Health snd Saf ety l

Three shipments of radioact:ve wast a were made during the period.

The shipments accounted for a total cf 21h e crs 'urshielded) with a total acttvity of 600 me.

The third shipment censt sted of tnree drums, each in J

a five ton shippirg c ask, Ine total acu vity cf the three casks was 950 mc.

1 Lne shipment cf spent fuel was cnde during the period, consisting of ten elements with a total activity of 1 395 megacuries.. Ormma radiation i

levels on contact with tne cask were generally less than 2 mr/hr with a maximum of 6 mr/br at the valve box.

Neutron radiation levels at one meter were approximately 0.1 rrad/hr fast -ith ro detectable slew reutron levels.

Beta-gamma contamination levels shcwed a maximum of 2 x 10-9 carles per 100 cm2-There was no cetectable alpha :ct. tar.natien.

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During Eecambcr tbe waste dispora; 1:cu d releases totalled

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195,000 gallons conta:narg 22.61 m: cf gross reta ganna activity and 193.75 curies of tritium Gasaous vaste re2 eases cu-rg me same per:od totalled 13h>h m: of gross oete-gamma a-::vity-O In addit or

'.o tre etcve liquid vaste releasa:, a tctal of 166,000 gallons cf water were d:scharged f rom the sacondary plant.

The total gross beta-gamma and tritium activities raleased from the secondary plant were 35 9 u: and 30 53 curler, respect:vely j

l Radiation exposere deses for Yankee plant pe r 'or.nel, as measured by film badge, for the mentn of Decemba, 1966, wera-

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Average ece cmulat uc exposure cos e 98 mrem Fhximcm accumulated exporure dose 687 mren.

Operations The followtng Fmergarey :nstructier was rev sec and reissued during U 505 B 10 1ctal Im cf KunC:clw i

Attached is a summary cf plant cparatu g m st a r t::s and a plot of

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daily average load fo-the conth cf Ia:ecter, 1966 I

KEE ATOMIC COMPA!U DAILY AVERAGE ICAD for DECEMBER,1966 200 -

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Ioad reduction for three loop operation.

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d (b) Shutdown No. 86-6-1 A

(c) Shutdown No. 87-6-2 m

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YANKEE ATOMIC ELETRIC COMPANY -- OPERATING SUMKtRY DEEMBER,1966 ELETRICAL

}0 NTH YEAR TO DATE Gross Generation WH 126,Y06,500 1,371,619,600 6,362,h60.500 Sta. Service (While Ge::. Incl. Losses)

Wil 7,506,91h 83,610,328 h30,022,822 Net Output Wil 119,199,586 1,288,009,272 5,932,h37,678 Station Service 5.92 6.10 6.76 Sta. Service (While Not Gen. Incl. Iosses)

Wii 19,208 1,553,889 23,795,h67 Ave. Gen. For Month (7hh hours)

W 170,30b Ave. Gen. Running (738.98 hours0.00113 days <br />0.0272 hours <br />1.62037e-4 weeks <br />3.7289e-5 months <br />)

W 171,h61 PIANT PERFORMANCE Net Plant. Efficiency 29.17 28 53 28.h6 Net Plant Heat Rate Bru/WH 11,700 11,962 11,991 Plant Operating Factor 91 55 85.89

't 33 Reactor Plant Availability 99.60 89 58 61 99

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NUCLEAR 10NTII CORE VI TOTAL Hours Critical HRS 7hl.0h 1,3hl.29 h5,066.97 Times Scrammed 2

2 Burnup Ora Average WD/MPU 819.61 1,h80.71 Region Average ND/MPU A (INNER) 810.12 1,hp5.%

18,268 h6 B (MIDDLE) 981.63 1,782.68 9,h57.97 C (OUTIR) 658.29 1,176 70 1,176.70

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