ML20195G569

Forwards Response to Generic Ltr 88-03, Steam Binding of Auxiliary Feedwater Pumps. Operating Procedures & Temp Monitoring Thermocouples Are Permanent Mods & Will Be Maintained in Effect

ML20195G569
Person / Time
Site:	Mcguire, Catawba, McGuire, 05000000
Issue date:	05/26/1988
From:	Tucker H DUKE POWER CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
REF-GTECI-093, REF-GTECI-NI, TASK-093, TASK-93, TASK-OR GL-88-03, GL-88-3, IEB-85-001, IEB-85-1, TAC-67226, TAC-67227, NUDOCS 8806280054
Download: ML20195G569 (4)

Text

-_.

7

, f ie ,

Dtmn POWER Goxvm

• P.O. HOX 33180 CHARLOTTE. N.C. 28242 HALH. TUCKER- tztzenoxz m e rans m ut (704) 073-4SlM swtaan raceumos May 26.,1988 ,

y U.S. Nuclear Regulatory Commission Document-Control Desk Washington, DC 20555

Subject:

McGuire Nuclear Station Catawbc Nuclear Station Docket Nos. 50-369 and 50-370; 50-413 and 50-414 NRC Generic Letter 88-03 Steam Binding of Auxiliary Feedwater Pumps Gentlemen:

Mr. F. A. Miraglia's (NRC/0NRR) February 17, 1988 letter (Generic Letter 88-03) concerned resolution of generic safety issue 93, "Steam Binding of Auxiliary Feedwater Pumps". This generic letter was issued to inform of the staff's resolution of the subject generic safety issue and to request (as a minimum) continued implementation of the monitoring and corrective procedures previously identified for interim resolution of this issue in NRC/0IE Bulletin 85-01.

Bulletin 85-01 requested that certain licensees and all construction permit holders implement procedures both for monitoring the AFW piping temperatures for indication of possible backleakuge and for restoring the pumps to operable status if steam binding were to occur. The bulletin was not issued for action for all holders of operating licenses for PWRs because the staff had determined that a number of them had already taken actions that would minimize the occurrence of the AFW pump steam binding problem at their plants.

Consequently, the bulletin was issued for action to Catawba Unit 2 (which had a construction permit at the time), and was f or information with respect to ,

Catawba Unit 1 and McGuire Units 1 and 2. However, the generic letter requested that all addreasees (including Catawba Units 1 and 2 and McGuire ,

Unita 1 and 2) provide a letter of confirmation to the NRC within 90 days of receipt of the generic letter indicating that the procedures discussed in the generic letter (i.e. those of Bulletin 88-05) are in place and will be maintained. This confirmation was requested even for addressees who were not issued the bulletin for action because the staff believes that they would rely.on these procedures as part of the actions to minimize the occurrence of the AFW pump steam binding problem.

Accordingly, this letter constitutes the requested confirmation for McGuire Units 1 and 2 and Catawba Units 1 and 2, as further described in the attachments.

(e 8806200054 DR 080506' p ADOCK 05000:169 PDR ( l k . _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . . _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ __. ___ __.__._.___.__.___ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ . . _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ . _ . _

.4 i

Document Control Desk '

May 26, 1988 -

Page 2 I declare under penalty of perjury that the statements set forth herein are true and correct to the best. of my knowledge. Should there be any questions concerning this. matter or if additional information is required, please advise.

Very truly yours, la A nsf Hal B. Tucker PBN/93/ bhp Attachments xc: Dr. J. Nelson Grace Regional Administrator U.S. Nuclear Regulatory Commission Region 11 101 Marietta St., NW, Suite 2900 Atlanta, GA 30323 Mr. W.T. Orders NRC Resident Inspector McGuire Nuclear Station Mr. P.K. Van Doorn NRC Resident Inspector Catawba Nuclear Station Mr. Darl Hood Office of Nucient Reactor Regulation U.S. Nuclear Ret,ulatory Commission Washington, DC 20555 Dr. K.N. Jabbour Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555

.~ ,

- DUKE POWER COMPANY

. McGUIRE NUCLEAR STATION, UNITS 1 AND 2 RESPONSE TO NRC GENERIC LETTER NO. 88-03 Action Item 1: Maintain procedures to monitor fluid conditions within the AW nystem each shift duririg times when the system is required to be operable. This monitoring should ensure that fluid temperature at the AFW pump discharge is maintained at about ambient levels.

Response: During the period that check valve backleakage was a problem, McGuire would monitor the piping upstream of check valves with a pyrometer. McGuire maintained a temporary log in order to trend the temperature change. During replacement of the check valves, McGuire installed strap-on thermocouples on the piping which provided Operator Aid Computer (OAC) alarms and input to a auxiliary feedwater (CA) system graphic for monitoring temperatures. The operators responsible for making daily rounds in the area of the _ CA Pumps check the suction and discharge piping by touch and then document this on their roundsheet.

Action Item 2: Maintain procedures for recognizing steam binding and for restoring the AFW system to operable status, should steam binding occur.

Response McGuire currently has operating procedures which require monitoring of check valve temperatures and provide a maximum temperature limit (depending on whether CA Pump is running or not running). If temperatures approach these limits, the procedure directs cooling of the pipinr by either running the pump of isolating the associated line. (CA is then declared inoperable). If temperature exceeds these limits and steam formation is indicated, then the discharge isolation valve is closed. The line is refilled with condensate water and vented before returning to service.

The above mentioned operating procedures, roundsheets, Operator Aid Computer (OAC) Alarms, OAC Graphics, and temperature monitoring thermocouples are permanent modifications and will be maintained in effect.

I l

a

. DUKE POWER COMPANY CATAWBA NUCLEAR STATION, UNITS 1 AND 2 RESPONSE TO NRC GENERIC LETTER NO. 88-03 Action Item 1 Maintain procedures to monitor fluid conditions within the AFW ,

system each shift during times when the system is required to be operable. This monitoring should ensure that fluid .

temperature at the AFW pump discharge is maintained at about ambient levels.

Response: Currently, Catawba is relying on temperature indications on the Operator Aid Computer (OAC) fed from strap-on thermocouples mounted on the piping upstream of the check valves that could allow backleakage. These temperature indications have the capability to alarm and alert the control room of backleakage.

In addition, these temperature indications are monitored daily by the operator while in Modes 1, 2, and 3. In the event that the computer is not in service, the rounds sheets and procedures specify that temperature readings are to be taken locally using a hand held pyrometer.

Action Item .2: Maintain procedures for recognizing steam binding and for restoring the AFW system to operable status, should steam binding occur. i r

Response: Catawba currently has operating procedures which require a check of the temperature of the discharge piping of all three Auxiliary Feedwater Pumps. These procedures require the venting of the pump if temperatures exceed the possible flashpoint based on system design and operating parameters. If temperatures near the check valves or at the pumps approach the flashpoint, operators are directed to cool the piping downstream of these pumps.

1