ML19309A885
| ML19309A885 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 03/28/1980 |
| From: | Lundvall A BALTIMORE GAS & ELECTRIC CO. |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19309A886 | List: |
| References | |
| NUDOCS 8004010463 | |
| Download: ML19309A885 (3) | |
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BALTIMORE GAS AN D ELECTRIC COM PANY P. O. D O X 1475 B A LTI M O R E. M A RYL A N D 212 03 March 28, 1o80 ARTHUR [. LUNOVALL,JR.
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Su p*Lv Office of Nuclear Peactor Berulation U. S. Nuclear Regulatory Comission Washington, D. C.
20555 Attn:
Mr. D. G. Eisenhut, Acting Director Division of Operating Peactors
Subject:
Calvert Cliffs Nuclear Power Plant Units Nos. 1 & 2, Dockets Nos. 50-317 & 50-318 NRC Recuirenents for Aux Feed Systens Referencer:
(n) NRC letter dated 11/7/79 fron D. G. Eisenhut to A. E. Lundvall, Jr., Auxiliary Feedvater Sycten.
(b) BG&E letter dated 12/13/79 from A. E. Lundvali, Jr.
to D. G. Eisenhut, same subject.
Gentlemen:
Reference (a) snecified certain requirements concerning the desicn, operation and testing of the Auxiliary Feedvater Systens at Calvert Cliffs.
Reference (b) provided our schedules and connitments for inolenentation of those requirenents. The following is a more detailed description of our proposed design changes to satisfy the long-tern requirements of Reference (a).
In order to satisfy the requirements of Reconnendation GS-5, the existing auxiliary feedvater systen vill be modified so that it can function during a loss of AC power. The existing steam supoly notor-operated valves (MOVs) vill be renlaced with fail-onen air-operated valves.
Each valve actuntor dic.nbracn vill be vented throuch two nornally closed, fail-open, solenoid vrJves such that either solenoid valve can vent the dianhragm. One rolenoid valve vill be deenergized on receint of a channel A AFW actuation signal.
The other solenoid valve vill be deenergized on receipt of a channel B AFV actuation signal.
As discussed in Reference (b) concerning reconnendations GL-1, the existing steam turbine systen vill also be modified to acconnodate automatic isolation of a runtured stean generator by the addition of two redundant Luxiliary feedvater isolation valves in each AFW header in series with and unstrenn of each AFW reculating valve.
Each isolation valve vill be a nornnlly-onen, fail-open, air-onerated valve with the air sunnly backed up by an accumulator.
One isolation valve upstrean of the intact stean bb I
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Mr. D. G. Eicsnhut f&rch 28, 1080 generator vill be closed on receint of a channel A " steam generator runture signal" (SGRS), and the other isolation valve vill be closed on receint of a channel B SGPS.
A SGRS would be generated if a lov level signal is received on a steam renerator concurrent with a signal sicnifying that the cressure in that steam renerator is lover than the nressure in the other steam generator by a certain predetermined value.
Auxiliary feedvater to an intact steam generator vill be automateially fed on low level in either steam generator. Steam nenerator level was selected for auto initiation because it is a direct indicator of the capabil-ity of the generator to act as a heat sink for the reactor coolant system.
The auto start signal vill be locked in and vill be resettable only when both steam generator levels are restored above the lov level setnoint.
The steam turbine driven auxiliary feedvater pumns vill be brought un to a maximum sneed on generation of a punn star' signal. The auxiliary feedvater regulating valves vill be set to a predetermined position when the need for aux feed is established. The system vill allow the operator to take remote manual control of the regulating valves.
Full remote manual control of the system by the onerator vill be retained. System design allows auxiliary feedvater to be automatically or manually initiated. Manual initiation can be acconolished using either of two nuchtuttons or by individual valve control handsvitches, all located in the control roon.
Automatic shut-off of aux feed on a high SG level signal vill urevent overfeeding a steam renerator. On detection of high level the isolation valves in the auxiliary feedvater header vill shut.
All AFW pumps vill continue to run.
As originally proposed in Reference (b), an electric-notor driven aux feed pump train vill be added to back-un the existing, turbine driven aux feed nunn train in resnonse to Pecommendations GL-2, GL-3 and GL-5.
The motor driven train vill be housed in a new seismic Class I, missile and tornado nroof building.
Both the existing and the motor-driven trains vill drav vater through senarate suction headers from condensate storane tank No. 12 which is also housed in a seismic Class I tornado and missile nroof structure.
The normal source of nover for the new AFW nunn and auxiliaries vill be offsite tower. Diesel generator nover vill be automatically pro-vided when offsite power is unavailable.
Enclosure No. 1 is a simplified P&ID showing the motor-driven and steam-driven trains of the integrated aux feed system as currently proposed. Enclosure No. 2 is a sinnlified logie diagram for the integrated aux feed control system.
The estimated ccanletion date for the total effort, which involves construction of the new building, procurement 'and installation of equinment including diesels, pumps, valves, switchgears, cable, controls, and instru-mentation, and installation of piping, is January 1,1983.
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. o A safetv-related locked-in auto-start of the existing steam turbine driven auxiliary feed rumns on icv level in either steam generator vill be innlemented by January 1, lo81. Detection of a runture and automatic isolation of the ruutured renerator will~not be in service by January 1, 1981 due to tine constraints associated with delivery of hardware.
h e system nronosed for next January 1 vill be a safety-related version of the control crade system installed to meet the January 1,1980 MEEG 0578 requirements except that auto-start will occur on low level in either steam generator rather than on loss of =ain feedvater. This is an interim measure to be installed to meet the January 1,1981 mmEG 0578 requirements.
The complete logic system including auto isolation of a ruutured generator vill be implemented as soon as possible thereafter.
In order to accomplish these modifications on a timely basis, we vill need your comments tromptly.
If you have any questions, please call us through our IEC Pro.1ect Manager, Mr. E. L. Conner, Jr.
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J. A. Biddison, Esquire G. F. Trowbridge, Esquire Messrs. E. L. Conner, Jr.
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