BECO-87-195, Submits Current Status of Improvements Being Implemented in Response to NUREG-0737,Item II.F.2 & Generic Ltr 84-23. Improvements Include Instrumentation for Reactor Water Level Sys & Installation of Analog Trip Sys

Submits Current Status of Improvements Being Implemented in Response to NUREG-0737,Item II.F.2 & Generic Ltr 84-23. Improvements Include Instrumentation for Reactor Water Level Sys & Installation of Analog Trip Sys

ML20237A136
Person / Time
Site:	Pilgrim
Issue date:	12/08/1987
From:	Bird R BOSTON EDISON CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
RTR-NUREG-0737, RTR-NUREG-737, TASK-2.F.2, TASK-TM BECO-87-195, GL-84-23, TAC-45159, TAC-60936, NUDOCS 8712140284
Download: ML20237A136 (4)

Text

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NUREG-0737, II.F.2 gi GL 84-23 BOSTON EDISON Executive Ofhces 800 Boylston street Boston, Massachusetts 02199 December 8, 1987 Ralph G. Bird BECo 87- 195 senior Vice Pn:sident - Nuclear U. S. Nuclear Regulatory Commission Document Control Desk Kishington, DC 20555 License DPR-35 Docket 50-293 REQUEST FOR ADDITIONAL INFORMATION NUREG-0737. ITEH II.F.2 (TAC 45159)

References:

1. Telecon (BECo 4.87.064), G. Whitney (BECo) to T. Huang (NRC), l August 3, 1987, subject: as above.

2. BECo letter 84-200, H. Harrington (BECo) to D. Eisenhut (NRC),

November 28, 1984, subject: Generic Letter 84-23: Reactor Vessel Hater Level Instrumentation in BHR's.

3. BECo letter 85-099, H. Harrington (BECo) to D. Vassallo (NRC),

May 28, 1985, subject: Generic Letter 84-23: Reactor Vessel Hater Level Instrumentation in BHR's.

4. Letter, D. Vassallo (NRC) to H. Harrington (BECo), June 11, 1985, subject: hUREG-0737 Item II.F.2, Inadequate Core Cooling Instrumentation.

5. Letter, R. Auluck (NRC) to J. Lydon (BECo), March 3, 1987, subject: Analog Trip System (TAC 60936).

Dear Sir:

This letter provides the current status of two improvements Boston Edison Company (BECo) is implementing for Pilgrim Nuclear Power Station in response to NUREG-0737, Item II.F.2 and NRC Generic Letter (GL) 84-23. The improvements are: the instrumentation for the reactor water level system and the installation of an analog trip system in place of mechanical level indication equipment. Status was requested in Reference 1.

References 2 and 3 describe the actions BECo is taking to improve the reactor water level instrumentation and install the analog trip system. Reference 4 acknowledged receipt of References 2 and 3 and indicated the BECo proposed improvements were consistent with the recommendations in GL 84-23. Reference 4 concluded with a request for BECo to provide the documentation required for Item II.F.2 and any appropriate Technical Specification changes. In letters dated February 27, 1986 and October 20, 1986, BECo submitted the appropriate Technical Specification changes. These changes were approved as Amendment No.

99 to the Pilgrim operating license in Reference 5.

hg0N 8712140284 87'208 DR ADOCK 050 3 \ g s\g

BOSTON EDISON COMPANY-U. S. Nuclear Regulatory Commission December 8, 1987

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l Effective 9/24/87 the hardware installation for both modifications is

. complete. By. the end of Refueling Outage #7, BECo expects to: complete plant

! testing, finish implementing the applicable procedural changes, and finish the required training. The Analog Trip System modification was installed under Plant Design Change (PDC) 84-70. A summary description of the modification is included as Attachment 1. The Reactor Hater Level System modification was installed under PDC 85-07. A summary description of the modification is included as Attachment 2.

BECo believes the information provided in response to the references listed above completes the response to NUREG-0737 Item II.F.2. If any additional information can be provided, please contact us.

1 R. G. Bird JFS/jcp/1289 Attachments: 1. Summary Description of Analog Trip System Modification

2. Summary Description of Reactor Hater Level System cc: Mr. R. H. Hessman, Project Manager Division of Reactor Projects I/II Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission 7920 Norfolk Avenue Bethesda, MD. 20814 U. S. Nuc7, ear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406 Senior NRC Resident Inspector Pilgrim Nuclear Power Station

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ATTAC4 MENT 1 TO BECO 87-195

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SUMMARY

DESCRIPTION OF ANALOG TRIP SYSTEM MODIFICATION The Analog Trip System (ATS) is a multi-channel signal conditioning system with built-in calibration capabilities. It provides accurate, easily calibrated, trip output signals for processes remotely monitored by 4-20 ma transmitters. The trip unit output signal drive can be used as an input to relays for equipment initiation and annunciator interface. An auxiliary 1-5 volt DC analog output is available for driving external moni toring or recording equipment.

Certain engineered safeguard sensor trip inputs for the Reactor Protection System (RPS), Primary Containment Isolation System (PCIS), and Emergency Core Cooling System (ECCS) are being changed from contact switches to analog '

transmitters with electronic trip units and output relays. These changes are being made to provide for continuous monitoring of the affected variables, to improve testing procedures and capabilities, and to improve operational characteristics such as fewer instrument testing-related scrams and fewer instrument valving errors.

Selected signals (i.e. reactor water level, reactor pressure, and drywell pressure) are being combined into common transmitters with multiple slave trip units.

The system is an electronic trip unit system which is testable in place. It incorporates a readout for each sensing loop that continuously displays the parameter being monitored during operation of the plant. In addition, the test current is displayed numerically with high resolution to achieve setpoint accuracy requirements imposed by system specifications.

Envi ronmentally-quali fied Rosemount Model 1153 Series B (output Code R) nuclear grade transmitters are being installed as the sensing devices, providing tha input signals to the trip units. These transmitters provide precision pressure measurements i r, nuclear applications requiring reliable performance and safety over an extended service life. These transmitters are ,

1 specified to be tested per IEEE 323-1974 for environmental qualification and  !

IEEE 344-1975 for seismic qualification. )

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ATTACHMENT 2 TO BECO 87- 195 '

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SUMMARY

DESCRIPTION OF REACTOR HATER LEVEL SYSTEM MODIFICATION' NRC Generic Letter 84-23 requires Pilgrim Nuclear Power Station to implement improvements that will reduce level indication errors caused by high drywell temperatures. These improvements include mitigation of inaccuracy effects due

.to reference leg overheating by reduction of the vertical drop inside the drywell.

This modification will remove the existing Yarway heated reference columns from the drywell, and install new cold reference legs outside the drywell. To 1 obtain a minimum vertical drop inside the drywell, two new primary containment liner penetrations are being installed. This will result in a reference leg vertical drop inside the drywell of approximately l'0".

.The new reference leg vertical drop will approximately equal the variable leg vertical drop inside the drywell, which will make the associated reactor water level instruments almost entirely independent of drywell temperature. The feedwater reference legs will not be modified but will maintain their original plant configuration.

New local reactor water level indicators are being installed at the transmitter racks replacing the old indicators. The new instruments are for local indication and are safety related for pressure boundary purposes. They are installed on racks containing other safety related components and are structurally supported to satisfy Seismic Class I criteria. Also, the density compensation to the feedwater control system level instrumentation will be removed to reduce the mismatch between the Feedwater Control Level Monitoring System and the new cold reference leg level monitoring system.

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