ML19345A346
| ML19345A346 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 03/23/1962 |
| From: | Coe R YANKEE ATOMIC ELECTRIC CO. |
| To: | US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 8011190164 | |
| Download: ML19345A346 (5) | |
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1 Pronosed Chance rio. 21 YANKEE ATOMIC ELECTRIC COMPANY YAriRT. E
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Attention: Division of Licensing and Regulation n
Referenec License No. DFR-3 (Docket No. 50-29) p ( i. e A,.
Dcar Sirs:
pursuant to paragraph 3.A of License No. DPR-3, as amended, Yankee Atomic Electric Company hereby requests authorization to make the folicwing changes FROPOFFD CHANG:
Reference is made to Section 226 of the license applica-tion, "Electriccl System", and particularly to drawing c699-TE-1D which fcilons page 226:1 of the text. 7lc propose to change the electrical supply for the radiation monitoring and feedwater control rystems from the exist-ing 120 volt AC vital but to a statien s.orvice bus 1ccaticn.
We further propose that conncctica of this equipa2nt be made to a feeder connected to the 460 volt station service bus designated as "'.001 - Bus I;o.
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This feeder precently supplies items of equipner.t such at the valve cpcratcrs for the safety injection cyctec, the centrol red selcction and program controls, tio. I main transformer and other essential 120 volt AC instru-mentation which are vital to the ncrmal and safe operaticn of the plant.
Reasons for Chance: Review of a rccent spurious reactor scram, its causes and possible action to prevent a recurrence, indicates that a rearrangement of electrical feeds. to certain process instrumentation is desirable. Further study has shown that elimination of the air particulate monitoring and feedwater control system electrical cup-plies fica the AC vital bus is feasible tince informatien displayed by this equipment need not be continuous during a total loss of power condition. As indicated in the paragraph belew, " Safety Considera-tiens", -- electrical supply is re-cstablished to the inst;
'ntation after a short time interval during which manual twitching is accomplished.
It is, therefore, proposed that the above electrical feed rearrangement be executed in order to cffectively reduce the exposure of the A0 vital bus to electrical grounds.
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. U.S. Atomic Energy Coci:nission Proposed Change No. 21 Attn.: Div. of Lic, and Reg.
March 23, 1962 Coc=cnwealth of Massachusetts Suffolk, es March 23, 1962 Then personally appeared before ce Roger J. Coe, who, being duly sworn, did state that he is a Vice President of Yankee Atomic Electric Com-pany, that he is duly authorized to execute and file the f oregoing request in the name and on behalf of Yankee Atomic Electric Company, and that the stater.ents therein are true to the best of his knowledge and belief.
John Jy/ Mack Notary Public q
My C h ission expires February 8, 1968 l
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U.S. Atomic Energy Co::cission proposed Change No. 21 Attn.: Div. of Lic, and Reg.
March 23, 1962 Safety Contiderations:
In our opinion, the proposed change does not present significant hazards considerations not described or implicit in the license application as amended to June 23, 1961, the date of issuance of Amendment No. 3 to License No. DPR-3, and oces not affect the accident analysis set forth in Section 4 of the license application.
Continuity of electrical supply to the relocated radiation moni-toring and feedwater control system circuits is assured by a firm 450 volt source provided with automatic throwover equipment between two 480 volt feeders connected to different bus sections. The bus sections are, in turn, supplied from different high voltage transmission lines.
In addition, the relocated radiation monitoring and feedwater control supply systems will each be provided with a break-before-make switch, the alternate switch position providing an electrical feed from the inverter. In the event of loss of both transmission lines, the switch is manually positioned to the inverter supply.
Schaduline of Chanoa: This change will be made at the time of the next refueling operation.
The proposed change requires authorization by the Co: r.ission pursuant to paragraph 3. A of the licence, since it involves a change in the design specifications of the reactor whir:h are set forth in the license appli-cation and incorporated by reference in the technical specifications.
(See paragraph B.2 of Appendix A to License No. DPR-3.)
Enclosed herewith at supporting information for the proposed change, in draft form, are superseding pages for the license application, 1
as fcilows:
9699-FE-lD (to supersede Revision No. 7) 226:3 (tosupe:secepage226:3dsted9/15/59)
Upon authorization oi this change and upon completion of the work superseding pages will be submitted in final forn as an amendment to the license application. Their incorporation in the licence application will bring the document up to date so that it will reflect the actual physical condition of the plant.
Upon inspection of the accompanying drawing 9699-FE-lD, it is also noted that a pressurizer watthour meter electrical feed is also con-nected to station service f.CC1 - Bus No.1.
This installation was accom-plished prior to the issuance of facility license No. DPR-3 on July 29,1960, but subsequent to the submission of the Final Hazards Sur.ary Report on Ecptember 15, 1959. The accompanying drawing now shows the actual physical connections of electrical equipment 5t the plant.
Respectfully submitted, Yt :.EE ATOMIC ELECTRIC COMPANY MQKrE fiogo'r; pre. Cop, J
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o 226:3 DRAFT Station Service Station service power is supplied through three forced air-cooled transformer units. Two are of equal rating, 5.0/6.25 mva,115/2.h kv, 3 phase, 60 cycles and are connected one each to the 115 kv lines; while the third 5.0/6.25 nya,18/2.h kv, 3 phase, 60 cycles is connected to the out-door section of the generator bus. Each of these units normally supplies one section of the 2,h00 and h80 v bus, the latter through a 750 kva, 2,h00/
h80 v, 3 phase, 60 cycles self-cooled transformer.
The 2,h00 v indoor metalclad switchgear is equipped with 150 mva interruptirg capacity air circuit breakers and consists of three sections' of bus, normally operated independently, with the two bus tie breakers open.
Care has been taken in assignment of loads, so that the main station auxil-iaries are divided between the three sections with the main coolant pumps lo-cated one each on bus sections No. 2 and No. 3 and two on bus section No. 1.
The htter bus is fed from the generator. This arrangenent for the main coolant pumps was made so that, in the event of turbine trip, at least 50%
of normal main coolant flow will be maintained for 30 to 60 see from the inertia of the generator directly without switching or from bus sections No. 2 or No. 3 by manual transfer.
The safety injection system pump motors are connected, one each to bus sections No. 2 and No. 3.
Therefom, loss of the turbine generator due to mechanical or electrical faults or reactor scram does not affect the electrical supply to these units.
The h80 v indoor metalclad switchgear consists of three sections of bus, normally operated independently, with the two bus tie breakers open. -
Again the loading arrangement for each bus provides maximum reliability of operation of the plant by assuring to alternate pieces of equipment separate sources of supply from different bus sections. However, for single items of equip ent which are vital to the normal and safe operation of the plant, a firm h60 v, 3 phase source is supplied by providirg autenatic throwover fac-111 ties between two hSO v feeders connected to different bus sections. The equipnent Wich is supplied by this source is the valve operatero for the safety injection systems, the control rod selection and prograr:aing controls, No.1 main transformer oil pump motors and essential 120 v a-c instrunentation, exclusive of those supplied from the 120 v a-c vital bus. This supply also serves as an emergency source for the 120 v a-c vital bus, but must be switched into service manually.
2 Fcr nuclear, pressurizer, main coolanb and various princry process instrumentation which is vital for control and supervision during all phases cf phnt operation, a separate 120 v, single phase, 60 cycles supply is furnishe d.
This source, known as the 120 v vital bas, employs a synchronous inverter set which consists of a 10 np,125 v, shunt would dimet current motor directly connected to a 5 kw,120 v, single phase, 60 cycles generator.
The inverter is designed to. crerate continuously from the 125 y station battery and is supplied with voltage regulatira equipment which controls the excitation of the generator and motor, so as to limit the alternating cu~ rent voltage and frequency variations to plus or minus 3 and 1% respectively.
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