ML20210H263
| ML20210H263 | |
| Person / Time | |
|---|---|
| Issue date: | 05/28/1997 |
| From: | Miller D Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-3032, NUDOCS 9708130323 | |
| Download: ML20210H263 (7) | |
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Don,Millor - 5/28/97
.g fD48lh/q7 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS MANUTES OF THE JOINT MEETING OF THE ACRS SUBCOMMITTEES ON INSTRUMENTATION AND CONTROL SYSTEMS AND COMPUTERS AND ON ELECTRICAL POWER SYSTEMS OCTOBER 8, 1996 ROCKVILLE, MARYLAND INTRODUCTION The ACRS Subcommittees on Instrumentation and Control Systems and Computers and on Electrical Power Systems met on October 8,
- 1996, at 11545 Rockville Pike, Rockville, MD, in Room T-2B3.
The purpose of this meeting was to continue the review of the proposed Standard Review Plan (SRP) Sections and, Branch Technical Positions (BTPs) related to digital instrumentation and control (I&C) systems.
The Subcommittees also reviewed the status of NRC programs to address equipment vulnerabilities to lightning and other transients.
The entire meeting was open to the public.
Mr. Michael T. Markley was the cognizant ACRS staff engineer for this meeting.
The meeting was convened at 8:30 a.m. and adjourned at 4:00 p.m.
ATTENDEES ACRS D. Miller, Chairman R. Seale, Member G. Apostolakis, Member W.
Shack, Member J.
Barton, Member E. Quinn, ACRS Consultant T. Kress, Member M. Markley, ACRS Staff Princioal NRC Soeakers S. Agarwal, kES*
M. Chiramal, NRR*
F. Coffman, RES P. Loeser, NRR J. Wermiel, NRR Office of Nuclear Regulatory Research Office of Nuclear Reactor Regulation No written comments or requests for time to make oral statements were received from the public.
Approximately six members of the public attended the meeting.
A complete list of meeting attendees is in the ACRS Office File and will be made available upon request.
p{()f The presentation slides and handouts used during the meeting are e
attached to the office copy of these minutes, j
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9708130323 970811 PDR ACRS 3032 PDR
Joint I&C Subcommittee
-2 October 8, 1996 Minutes Chairman's ooenina Remarks Dr. Don W. Miller, Chairman of the joint Subcommittee, convened the meeting at 8:30 a.m. and stated that the purpose of the meeting was j
to review the proposed Standard Review Plan (SRP) Sections and Branch Technical Positions (BTPs) Guides associated with digital It.C systems, and to review the status of NRC programs to address equipment vulnerabilities to lightning and other transients.
He j
said that the staff is requesting a letter from the ACRS regarding the acceptability of issuing the proposed SRP Sections and BTPs for public comment.
NRR Presentation Mr. Matthew Chiramal, Senior Advisor, Instrumentation and Control Branch, NRR, discussed the proposed update to the SRP Sections.
He reviewed the " ground rules" for the SRP Chapter 7 Update and provided an overview of the SRP Sections and associated BTPs.
He provided detailed discussion of the reactor trip system (SRP Section 7.2), data communications systems (SRP Section 7. 9), and guidance for performing software reviews (BTP-14).
Significant points made during the discussion includes e
Ground rules include maintaining existing regulatory bases, incorporating lessons learned from advanced light water reactor reviews and digital retrofits, and incorporating industry operating experience.
The SRP Chapter 7 Update contains criteria for NRC reviewers to evaluate licensee submittals of digital upgrades for both operating plants (retrofits) and future advanced reactor designs.
Reviewers of license amendment applications will determine the scope and depth of each review based on the safety significance and complexity of the proposed change.
This guidance will benefit licensees in better understanding the NRC process for acceptance of modifications and will provide more information for 10 CFR 50.59 safety evaluations, o
Defense-in-depth and divernity is required for reactor trip systems and engineered safety feature actuation systems, e
Review of 'SRP Section 7.2, Reactor Trip System, requires coordination with multiple NRC technical branches (i.e., broad organizational review and involvement).
l
Joint I&C Subcommittee October 8, 1996 Minutes e
SRP Section 7.9, Data Communication Systems, covers systems other than point-to-point cables (e.g., multiplexed systems involving optical ftber and electric cable t 'cansmission).
Data communication systems support more than one I&C system.
This-section instructs staff reviewers to pay special attention to the quality of components and modules, software quality, system performance, and reliability, e
Branch Technical Position-14, Guidance on Sof tware Reviews for Digital Computers-Based Instrumentation and Control Systems, provides guidance for the staff to perform safety determi-nations and to confirm that software was developed in accordance with acceptable software development standards, that plans were followed through an acceptable life cycle, and that the process produces acceptable design outputs.
The guidance does not require that applicants lock-in detailed designs.
The Office of Nuclear Regulatory Research has developed several regulatory guides associated with the appropriate SRP Sections and BTPs.
These guides endorse various IEEE Standards which provide methods acceptable to the staff in meeting NRC requirements, e
There are four groups of BTPs: (1) BTP 1-9 are existing BTPs, (2) BTP 10-13 reflect lessono learned from operating reactor
- reviews, (3) BTP 14, 17, 18, 19, and 21 deal with digital system issues, and (4) BTP 16 discusses level of detail for design certificatior applications.
Mr. Paul Loeser, NRR, presented pn overview. of-the Babcock and Wilcox STAR System reactor protection system digital upgrade.
The STAR System has four chann<. tis and it is unique becauso it contains four dif ferent microprocessors per channel. The sof tware for these microprocessors were developed independently by two different manufacturers.
The primary-review criteria for the STAR System were those includee in IEEE Standard 279-1971,
" Criteria for
- Protection Systems for Nuclear Power Generating Stations," and the guidance provided in the old Sections of the SRP 7.1 and 7.2.
Mr.
Loeser presented the STAR System as a case study to illustrate how an actual review would be-conducted by the NRC staff using the SRP and associated guidance.
RES Presentation Mr. Satish Aggarwal, RES, provided an overview of the NRC program for the development of a proposed regulatory guide to address protection for equipment vulnerability to lightning and other transients. Significant points made during the discussion include i
Joint 1&C Subcommittee 4-October 8, 1996 Minutes During previous discussion regarding this matter in 1992, the e
ACRS agreed with the staf f's conclusion that operating plants were adequately protected against lightning at this time, and that rulemaking was not warranted.
- However, the staff proposed to develop a regulatory guide and the ACRS agreed that this approach was apr>ropriate.
e The staff has not yet endorsed any industrial standards for equipment protection against lightning. The staf f still plans to develop a regulatory guide to sddress concerns in this area.
Regulatory requirements (General Design Criteria) include requirements for protection against natural phenomena (lightning is natural phenomena).
This includes basic design principles for protection of electrical power systems, and instrumentation and control systems from the effects of lightning (e.g.,
high voltage spike, direct hit and high frequency electrical transients propagating into the plant from the transmission line or switchyard, electrical distribution system and I&C systems),
The objective for the development of the regulatory guide is e
to provide guidance for lightning protection for all plant structures and components including the switchyard.
Final issuance of the regulatory guide is scheduled for December 1998.
The staff plans to brief the ACRS on the draft regulatory guide in September 1997 and the proposed final guide in July 1998.
Mr. Franklin Coffman, RES, discussed the status of Brookhaven National Laboratory risk screening study on Instrumentation and Control Systems.
The study included the evaluations of relative effects on risk from environmental stressors, including electro-magnetic interference associated with lightning.
He noted that this study concluded that digital I&C systems are vulnerable to lightning and other transients.
Subcommittee ouestions and CQmm2nt.A The Subcommittee extensively discussed the process for conducting reviews.
Drs. Apostolakis and Miller asked who determines the depth of each review and how to ensure consist' ncy.
The staff e
stated that the individual reviewers determine the depth of review in consultation with their supervisors.
The staf f also stated that the SRP guides the reviewer through the evaluation process but emphasized that judgement is required at each step of the review.
Joint I&C Subcommittee October 8, 1996 Minutes Dr. Apostolakia expressed the view that the guidance does not assure accuracy, consistency, and completeness for the staff reviews of licensee submittals.
The etaff described the review process and stated that the guidance provides a basic statement of what the reviewer should look for in conducting the review.
The Subcommittee questioned the level of details provided in the regulatory guides related to digital I&C systems.
Dr. Apostolakis expressed concern over acceptance criteria in BTP-14 and expressed the view that the documents were too general and that IEEE Standards were dif ficult to follow, Dr. Apostolakis reiterated his concern regarding the staff's emphasis on process versus product.
The staff stated that tha review should focus on requirements l
specification to reducq the reliance on finding problems during the testing phase.
Mr. Quinn added that the quality of the test procedures ensures that the process approach to software development works effectively.
Dr. Miller asked if the STAR System hardware /sof tware were reviewed as a system and whether the SRP/BTPs criteria were used for the l
review.
The staff stated that the STAR System was submitted as a l
Topical Report and that the safety evaluation report (SER) was issued prior to the SRP Chapter 7 Update.
The Subcommittee discussed the level of review for regulatory guides relative to that normally provided in SERs for industry sponsored Topical Reports.
The staff stated that a regulatory analysis was performed for each regulatory guide, but indicated that a formal SER was not completed.
At the close of the meeting, Subcommittee Members provided their observations and concerns.
Many of the specific issues were discussed in earlier Subcommittee meetings and noted in the ACRS letter dated June 6, 1996.
These include:
The level of detail provided in the regulatory guides.
The linkage between SRP Chapter 7 and other SRP Chapters, The balance in the guidance between the review of the design e
process and the assessment of the product.
Graded approaches based on importance to safety.
e Subcommittee Recommendations The Subcommittee requested the NRC staf f to address the above noted observations and concerns during the full Committee meeting, October 10-12, 1996.
The Subcommittee plans ACRS plans to continue its review of the SRP Update, BTPs, and regulatory guides.
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Joint I&C Subcommittee October 8, 1996 Minutes hiU;kground Material Provided to the committee for thic Meetina e
Draft Standard Review Plan, Chapter 7,
" Instrumentation and Controls," August 199E revision, e
Letter dated June 21, 1996, from J. Taylor, EDO, to T. Kress.
ACRS Chairman, Subj
" Regulatory Gaidar.ce Documents Related -
to Digital Instrumentation and Control Systems" Letter dated June 6,1996, from T. Kress, ACRS Chairman, to J.
e Taylor, EDO, Subj: " Regulatory Guidance Documents Related to Digital Instrumentation and Control Systems" e
Memorandum dated August 5,
1996, from J.
Calvo, NRR, to L.
Shao, RES, Subj
" Continuation of Developing Regulatory Guide on Lightning Protection for Nuclear Power Generating Stations" o
Letter dated February 24, 1993, from J.
Taylor, EDO, to P.
Shewmon, ACRS, Subj Response to ACRS letter dated December 17,
- 1992, regarding Petition for Rulemaking on Electrical Transients, PRM 50-56 Memorandum dated January 31, 1996, f rom Thomas E. Murley, NRR, to E. Beckjord, RES, Subj: "NRR Users Need for Development of a Regulatory Guide on Lightning Protection for Nuclear Power Plants" e
Report dated December 17, 1992, from P. Shewmon, ACRS, to I.
- Selin, Chairman, N.1C,
Subj "NRC Staff
Response
to the Petition Submitted by Richard Grill for Rulemaking on Electrical Transients, PRM-50-56" o
Memortndum dated September 16, 1996, from F. Miraglia, NRR, to E. Jordan, CRGR, Subj : " Request f or Review of Updated Standard Review Plan Chapter 7,
Instrumentation and Controls," and attachments e
Letter dated August 3,1995, f rom B. Boger, NRR, to J. Ta:' lor, EDO, Subj: " Safety Evaluation for Topical Report BAW-10(
D.
' STAR System Components for Reactor Protection System Digit.wl Upgrades, September 1994,"
e Technical Report L-1908, T6,
" Risk-Based Prioritization of Environmental Stressors Which Can Af fect Advanced Digital ILC Equipment in Nuclear Power Plants," dated March 1996 e
NUREG/CR-6316, Volume 1 of 8, " Guidelines for the verification and Validation of Expert System Software and Conventional Software," dated March 1995 l
t 7,.
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Joint;IEC Subcommittee
--7 October 8,-1996 I
4 Minutes t
2-ii NOTE:
Additional details of this meeting can-be obtained from i-a transcript of this meeting available in the NRC Public
~
Document Room, 2120 L Street,- N.W., - Washington, D.C.
20006, (202) 634-3274,- or can-be-purchased from Neal.R.
. Gross & Co., Inc., Court Reporters and. Transcribers,1323-Rhode Island Avenue, N.W., Washington, D.C.
20005, (202) 4 234-4433.
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