ML20211H821

Submits Results & Highlights of Technical Discussions with Instrumentation & Control Staff of Baltimore Gas & Electric Co,Calvert Cliffs Npp,On 990511 & 0714

ML20211H821
Person / Time
Site:	Calvert Cliffs
Issue date:	07/27/1999
From:	Calvert J NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES)
To:	Bahadur S NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES)
Shared Package
ML20211H825	List: ML20211H821 ML20211H843
References
NUDOCS 9909020184
Download: ML20211H821 (3)

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i MEMORANDUM TO: Sher Bahadur, Chief Engineering Research Applications Branch Division of Engineering Technology Office of Nuclear Regulatory Research m ._.

FROM: John A.Calven,SeniorI&C Engineer 50 Engineering Research Applications Branch //

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Office of Nuclear Regulatory Research { g ,/g]

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SUBJECT:

MEETING SUMMARIES OF RESEARCH STUDY ON THE CALV.ERTO  ?  :

CLIFFS NUCLEAR PLANT DIGITAL FEEDWATER SYSTEM Eg

References:

(1) letter, June 23,1999: John W. Craig, Office of Nuclear Regulatory, u B w

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Research, Director of the Division of Engineering, to Kevin Cellars, Baltimore Gas and Electric Company, Manager of the Nuclear Engineering i Department. Attachment i The purpose of this letter is to report the results and highlights of technical discussions with the Instrumentation and Control (I&C) staff of Baltimcre Gas and Electric (BGE) Company's Calven '

Cliffs Nuclear Power Plant. The subject was our research study on the reliability modeling of their digital feedwater system.

Summarv We held two meetings at the Calven Cliffs Nuclear Plant. In the first meeting on May 11,1999, we gave a presentation to the BGE I&C staff about the research objectives. Our cooperative research partner, the University of Virginia Electrical Engineering Department, also presented the technical over iew of the digital modeling they would use in the study. As a result of this meeting, BGE agreed to panicipate in the research study and we sent an acknowledgment letter to BGE (Reference 1). Attachment 2 lists the date, time, place and attendees at this first meeting.

We held the second meeting, called the Technical Interchange Meeting (TIM) No.1, on July 14, 1999, to discuss the functional details of the digital feedwater system, to receive the technical documentation, and to establish technical contacts. We received most of the documentation. The If h

proprietary documentation is awaiting arrangements from the vendor. The University of Virginia can use the received documentation to start the functional study of the system prior to modeling.

Attachment 3 lists the date, time, place and attendees of the second meeting.

l Obiectives of Digital Reliability Modeline Research John Calven discussed NRC's objectives regarding the digital reliability modeling research. By Ok i using design data from Calven Cliff's digital feedwater system, the NRC and its cooperative research member, the University of Virginia, are able to test prospective digital modeling techniques. The 0 .:,.MN l 9909020104 990727 i PDR ADOCK 05000317 j P PDR

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main benefit to BGE is first-hand exposure to the new analysis technology. Attachment 4 contains the slides from Mr. Calvert's presentation.

Digital Modeline Techniaue e Dr. Barry Johnson, of the University of Virginia presented excerpts from the digital reliability and safety modeling presentation that he gave to the NRC Advisory Committee on Reactor Safety (ACRS) on May 3,1999. He provided an overview of the digital modeling technique developed at the University of Virginia's Center for Safety-Critical Systems and described the process of modeling digital systems. He also prer,ented some results of past digital system studies using the digital modeling technique. The technique is unique in that it can model the actual software executing on the digital hardware. Most techniques model either the hardware or the software, but not both together as they are in an actual application. This allows modeling the effect of the interaction of hardware and software. Attachment 5 contains the slides from Dr. Johnson's presentation. j BGE Perceived Benefits of Dicital Modeline and Implementation BGE mentioned that a possible benefit of such modeling technology is a balanced approach towards capturing digital system faults in the design and operational stages. BGE also mentioned that the installed digital feedwater system has a significant, positive impact on the plant's core damage frequency. The main reason is that the faster algorithmic response of t!'e digital system helps prevent loss of feedwater after a plant trip so that feedwater is available for decay heat removal and alternate means do not have to be brought into play.

Plant Documergugn Bruce Geddes, of Baltimore Gas & Electric, presented overviews of the digital feedwater system and the digital feedwater controller. Design documentation, such as system / software requirements specifications, manuals, drawings, system design descriptions, and hazard analysis, were shown.

Some of the items are proprietary to ABB-CE, and arrangements to use those documents are expected soon. The University of Virginia took the documents that were not proprietary for their use in the study project. Attachment 6 is the Digital Feedwater (DFW) Documentation Inventory.

Dicital Feedwater Lab Bruce Geddes provided a tour of the digital feedwater lab. The lab contains the replicas of the digital feedwater controller and a simulator to drive the controller. This lab is used by BGE to validate the correct operation of the digital feedwater controller modifications before they go into the plant. The possibility of the University of Virginia using the lab was also discussed.

Attachments: As stated i Distribution: See next page l DOCUMENT NAME: g:\erab\jcalvert\jccmin2 To enceive a coat of this document, indicate in th i bor: "C" = Copy wthout ettschmentleneloswe "F* = c1Dv with attachment'encloswe 'N' = No copy 0FFICE ERAB/RES l ERAB/RES l l NAtiE JCalvert %g, SBahadur M DATE 7/fp/99 # R M /99 0FFICIAL RECORD COPY

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