ML20009C953

Submits Info Re Auxiliary Feedwater Sys Mods,In Response to NRC .Mods to Condensate Storage Tank Level Sys, Supplemented by Operating Procedures,Will Ensure That Adequate Supply of Makeup Water Is Available to Pumps

ML20009C953
Person / Time
Site:	Calvert Cliffs
Issue date:	07/15/1981
From:	Ash R BALTIMORE GAS & ELECTRIC CO.
To:	Clark R Office of Nuclear Reactor Regulation
References
NUDOCS 8107220225
Download: ML20009C953 (5)

Text

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BALTIMORE OAS AND ELECTRIC CHARLES CENTER. P.O. BOX 1475 BALTIMORE, MARYLAND 21203 ELECTRIC ENGINEERING July 15, 1981 oEPARTMENT 1

Office of Kuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C.

20555 Attn: Mr. Rabert A. Clark, Chief Operating Reactors Branch #3 Division of Licensing

Subject:

Calvert Cliffs Nuclear Power Plant Units Nos. 1 & 2; Dockets Nos. 50-317 & 50-318

_ Auxiliary Feedvater System Modifications

References:

(a) Letter from D. G. Eisenhut to A. E. Lundvall, Jr.

dated 7 November 1979, NRC Requirenents for Auxiliary Feedvater Systems at Calvert Cliffs Nuclear Power Plant.

(b) Letter from A. E. E,undvall, Jr. to 't.

A. Clark, same subject dated 18 November 1980.

Gentlemen:

Reference (a) forvar led for our action certain generic and plant-sp cific Auxiliary Feed ater System (AFWS) recommendations that resulted from the NRr's Bulletins and Orders Task Force Review. Also contained in Reference (a) were four additional short term recommendations which had not been reviewed by NRC for specific applicability to Calvert l

Cliffs Nuclear Power Plant. We have been considering all of the above recommendations in our ongoing design upgrade of the Calvert Cliffs AFW systems.

In response to Additional Short Term Recommendation No. 1, concerning redundant condensate tank levt.1 indications and alarms, we vill be making modifications to cui systems as described below.

At present, as shown in Figure 1, Condensate Storage Tank (CST)

No.12 has a local level indicator and-a leval transmitter which provides level indication and alarm at the Auxiliary Shutdown Panels (ASPS) and in the Control Room. In coniuaction *.ith the Auxiliary Feedvater (AFW) nodi v cations. as discussed in reference (b), we vill be installing r' additional level transmitter for CST No.12 and providing redundant indication in the control room and at'the ASPS, as shown in Figure 2.

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Mr. R. A. Clark Page 2 July 15, 1981 The following design criteria vill be met for the purchase and installation of the equipnent.

1.

The equipment vill be supplied in accordance with the IEEE requirements for class 1E equipment; i.e., IEEE 323-7h for environmental qualification.

2.

Complete isolation vill be provided between redundant circuits.

3.

ASP indication vill be concletely isolated from the control room, b.

The system vill meet the seismic criteria of I103 3hh-75 with the exception of the cable routing to the level transmitter of the CST.

This cable vill be routed through the non-seismic turbine building and existing pipe tunnel outside to the ccndensate tank area.

5 The system vill be single failure proof, with the exception of local indication.

6.

There vill be redundant indication in the control room and at the ASPS. In addition, the local level indicator is available.

Dual alarm capacity is installed.

7.

The cable routing vill meet -he physical separation criteria of IEEE-384.

8.

Each indicator vill be povered from a separate vital AC power source.

9.

The level indicators vill cover the fu]l range of CST level.

No reccrding cf instrumentation readout information vill be provided.

These modifications to the CST level system, supplemented by our operating precedures is discussed belov, vill ensure that an adequate supply of makeup water is available to the AW punps:

1.

CST No.12 has local and control room indication. These instruments are checked and logged every four hours by both the Control Room Ooerator and Outside Operators. This provides two independent level checks every shift. Any discrepancies betve-the two readings would be resolved.

2.

During any event where loss o* IP4 takes place, Abnormal Operating Procedure 15 (AOP-15) is effective. An operator is required to go to CST-12, check the valva line-up and CST-12 local level indication, and make preparations to switch from CST 12 to CST 11 (CST 21 for Unit 2).

Should both level indications be lost fnr CST 12 or if the control room indications were not in agreement with local level, an operator would be required by AOP-15 to take the same action as above.

u Mr. R. A. Clark Paga 3 July 15, 1981 3

If power was interrupted to the level transmittern, the indicaters would fail lov and the alarm would activate. This vould give the operator positive indication that the instrumen-tation had failed, and he vould take the actions as detailed in item 2 above.

h.

Should the loss of level indication occur during AFW pumo eneration, the operator vould have a backup control room alarm for low yuep suction pressure (existing). There is also discharge pressure and AFW flov indication in the cct. trol room.

If the operator were to receive these alarms or low discharge preasure or lov flow indication, he vould trip the AFW pumps to avoid damage, have the outside operator verify the level in CST 12 or change the lineun to CST 11 (CST 21) if necessary, and then rentart the F4 pumps. If the AFW pumps of the nfrected unit were damaged prior to tripping, AFR could So supplied 'via the cross-connect from the other unit's electrie driven AFW pump.

Although we are sending this letter for your information, in the interest of r.aintaining our schedule for the AFW modifications, if you have any comments or questions concerning our design, please contact us as soon as nocsible.

Very truly yours, R. F. Ash Chief Nuclear Engineer RFA/nmn Fnclosure cc:

J. A. Biddison, Esquire G. F. Trowbridge, Esquire

• %ssrs. E. L. Conner, Jr. - NRC J. C. Ventura - Bechtel P. W.

ruse - CE bec: Monsrs. R. H. Kent R. E. Denton/D. W. Latham R. F. Ash / File P. E. Katz/R. M. Stark A. R. Thornton G. S. Pavis R. M. Douglass W. C. Holston C. H. Cruse /C. J. Yoder J. E. Macklin/J. L. Lawson R. C. L. Olson R. P. Heibel L. B. Russell

e Mr. R. A. Clark Page 3.

July 15,1981 j

3.

If power was Interrupted to the level transmitters, the indicators vould fail lov and the alarm would activate. This-vould give the operator positive indication that the instrumen-

-tation had failed, and he would take the actions as detailed in item 2 above.

k.

Should the loss of level indication occur during AFW pump operation, the operator would have a backup control room alarm for lov i aq)-

suction pressure (existing). There is also. discharge pressure and AFW flow indication in the control roca. - If the operator i

vere to receive these alarms or lov dischaege pressure or low flow indication,' he vould trip the AFW pumps to avoid damage, have the outside operator verify the level in CST 12 or change the lineup to CST 11 (CST 21) if necessary, and then restart the AFW pumps. If the AFW pumps of the affected unit were damaged prior to tripping, AFW could be supplied via.the cross-connect from the other unit's electric driven AFW pump.

Although we are sending this letter for your information, in the interest of maintaining our schedule for the AFW modifications, if you have any comments or questions concerning our design, please contact us as soon as possible.

Very truly yours, R. F. Ash Chief Nuclear Engineer RFA/smn Enclosure cc:

J. A. Biddison, Esquire G. F. Trowbridge, Esquire j-

- Messrs. E. L. Conner, Jr. - NRC J. C. Ventura - Bechtel P. W. Kruse - CE i:

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