ML19305A481
| ML19305A481 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/04/1979 |
| From: | Wenzinger E Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19305A478 | List: |
| References | |
| NUDOCS 7907260458 | |
| Download: ML19305A481 (7) | |
Text
. _ _ _
N 8
4 UNITED STATES
- h
[
g NUCLEAR REGULATORY CCMMISSION O
WASHINGTON, D. C. 20065
\\
jE
~
\\"w]
APR 4 1979 MEMORANDUM FOR:
IAEA DISTRIBUTION FROM:
E. C. Wenzinger, Alternate U.S. Representative, IAEA TRC-Design
SUBJECT:
REPORT OF IAEA MEETINGS IN LONDON AND VIENNA, JANUARY 22 TO FEBRUARY 2, 1979 Purcose - Two meetings were held during the reporting period.
A task group of memoers of the TRC-Oesign and members of the author group on SG-08,
" Safety Related Instrumentation and Control Systems," met in London on January 22 to 26, 1976.
The purpose of this meeting was to complete review of TRC comments on 08 and to prepare a revision to 08 in response to the coments received from TRC members.
The full TRC-Oesign met in Vienna from January 29 to February 2, 1979 (1) to review Member States' comments on SG-03, " Protection Systems And Related Features In Nuclear Power Plants,"
3 (2) to review SAG comments on 50-07A, " Emergency Electrical Power Systems,"
and (3) to review comments on the scope of SG-Oll, " Selected Design Safety Principles."
~
Summary At the meeting in London on SG-08, " Safety Related Instrumentation and Con-trol Systems," the guide was revised in response to all the comments which had been received from TRC members.
This guide addresses "non-safety" reactor control systems and safety related instruments and controls which are not covered by SG-03 (on protection systems). A separate set of require-ments on "non-safety" control systems and a separate set of requirements on safety related I&C was prepared.
A new draft of 0-8 was cnspleted and was distributed at the TRC meeting during the week of January 29 to February 2, 1979.
At the meeting in Vienna the only guide to be discussed in detail was SG-03,
" Protection Systems and Related Features In Nuclear Power Plants." The discussions on SG-07A, " Emergency Electrical Power Systems," was not begun because nearly the entire time was spent on 03.
The principle reasons for the extensive time spent on 03 was the number of comments received on 03 1
(aoproximately 200) and the absence of the chairman of the TRC for 03 (Paul Wolff of UK), *ho was ill.
Ed Cobb of the UK (chairman of the TRC for 08) substituted for Mr. Wolff.
In addition, the principle FRG representative was George Fischer who had not participated in previous 03 discussions.
790726o4s l
t
{
IAEA Distribution 2
APR 4 1979 The discussion of all the comments on 03 was completed and resulted in extensive wording changes in the document.
To the best of my knowledge no principles were altered in the rewrite.
A re-reading will be needed to confirm this. The document will now be sent to the SAG for final approval.
Only one technical issue remains.
I believe the section on qualification should recuire testing to confirm qualification of safety systems' equipment (see Discussion).
The TRC did discuss one other topic, the scope of 50-011, " Selected Design Safety Principles." The scope was revised extensively.
The reason for the extensive revision was that each TRC member seemed to have a difficult idea of wnat the guide should cover.
The guide will cover topics of general interest to all TRC-Oesign guides.
It will basically be a detailed exten-sfon of the Code of Practice on Design in some areas.
I objected to work on this guide, in deference to work on other guides (e.g., containment, fuel design, primary system) but except for the representative from India 1
(Mr. Mehta) no one else agreed to change the scope of 011 to ar.other topic.
I had also objected when the 011 scope was originally prepared (November i
1978).
Our SAG member should object to the 011 scope at the next SAG meet-l ing on the basis that (1) the present scope of 011 nearly duplicates work
'aiready done in other guides and (2) more important guides will not be worked on if the current scope is adopted.
The next meeting of the TRC is being scheduled for Tokyo, Japan, if a formal invitation by the Japanese is received shortly.
Topics will be SG-04,
" Protection Against Internally Generated ;41ssiles and Their Secondary Effects In Nuclear Power Plants," and SG-05, " Man Induced Events." This meeting will be held April 30 to May 4, 1979.
This will be the last TRC meeting for the scientific secretary, Mr. Herschel Specter, who is return-ing to DOE in June 1979.
The following meeting will be held in Vionna, October 22-26, 1979.
Topics will be SG-07A on emergency electric systems and SG-06, " Ultimate Heat-Sink and Its Directly Associated Heat Transport Systems.
I currently plan to attend the October meeting in Vienna.
Mr. Norberg plans to attend the April meeting.
A list of attendees of the London and Vienna meetings is attached.
Discussion l
I.
SG-08, " Safety Related Instrumentation and Control System" This guide was discussed at the meeting in London on January 22-26, 1979.
l The principal purpose was '.o complete a first revision of this guide in response to comments received from TRC members in writing and comments received from the TRC at the TRC meeting in Vienna in November 1978.
l 1
1 I
j
IAEA Distribution 3
APR 4 1979 The principal difficulties associated with this guide were (1) defining the scope of equipment to be covered and (2) defining the requirements applicable to each set of equipment covered by this guide.
Regarding scope, this guide is an attempt to prepare a set of requirements aimed at I&C equipment which is not part of the safety system (or protec-tion system) but is important enough that it can be considered important to safety.
In the U.S.,
some of this equipment has been referred to, at times, as Class 2E.
As currently written, the guide attempts to break the covered equipment into two major categories:
(1) Reactor Control Systems and (2) other I&C systems important to safety which are not part of the safety system or are not covered by other specialized guides such as 02 on Fire Protection, 07A on Emergency Electric Systems, and 09 on Radiation Monitors.
Separate requirements and recommendations are given on the con-trol systems and on the other I&C systems in 08.
Figure 1 in 08 gives a detailed breakdown of 08 coverage.
The " requirements" in this version of 08 on reactor control systems are only eluded to.
The reason for covering these systems are as follows:
(1) failures in the reactor control systems may impose a demand for action by the protection system, i.e., control system failures are " postulated initiating events" for the protection system.
Clearly, frequent demands on the protection system must not be allowed (see Sections 2, 2.1 and 2.2 of 08); (2) Reactor Control Systems must maintain process variables within certain limits if safety analysis assumptions are to be maintained valid.
Extreme changes in control system performance must be made highly unlikely.
08 calls for specification of test and alarm provisions commensurate with expected failure rates of control system equipment.
08 also notes that some Member States place reliability goals on reactor control systems.
The remainder of the 08 guide is devoted to other safety related I&C.
This includes equipment in fuel handling and storage -I&C system, monitors of the state of safety systems, ultimate heat sink I&C, control room design, etc.
Excluded is safety system equipment, covered in 03, emergency power system I&C', covered in 07, and special requirements unique to systems, such as radiation monitoring (covered in 09) and ultimate heat sink I&C (covered in 06).
Requirements on the equipment covered by 08, but not Control Systems, is divided into three categories.
These categories are based on conse-quences of failure and the time available for operator action.
Category I, high consequences and a short timescale (1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> or less), calls for redun-dancy. Category II suggests (uses "may") redundancy, and Category III sug-gests redundancy is unnecessary. General requirements are also included on separation of redundant 08 equipment, qualification, testing and cali-bration, maintainability.
Except for redundancy requirements and recom-mendations, and power supply requirements, all the rest of the 08 provisions apply across the board (again, except for control systems).
l IAEA Distribution 4
APR 47979 While this revision of D8 is only a small step toward defining a set of requirements somewhere between Class IE and non-safety equipment, it is a beginning.
The IEEE has tried, and failed to prepare a document on 2E equipment.
Perhaps with NRC staff assistance and IEEE participation, a viable 08 guide can be developed for U.S. as well as international use.
A copy of 08 is available from the undersigned.
Comments are invited for use in preparing the next revision.
II.
SG-03, " Protection System and Related Features" A little more than four full days were spent reviewing nearly 2/3 of the two hundred comments received from Member States on this guida.
Previous to the meeting, Mr. P. H. W. Wolff (U.K.), Chairman of the TRC for 03, had reviewed all the comments received.
He had proposed to the TRC, in writing, a proposed resolution for each comment.
Nearly 1/3 of Mr. Wolff's proposals were accepted as proposed. Another 1/3 were more or less accepted with minor changes after discussing the points at issue.
The final 1/3 were discussed and the comments were resolved in some manner other than that which Mr. Wolff had suggested.
Three major points were discussed which merit reporting individually.
(1)
In previous discussions, the U.K. and, more strongly, the FRG representative argued long and hard for mandatory provisions in the guide on " fail-safe" design. Other members, particularly myself and to a lesser degree the Indian representative (Mr. Mehta), argued that such requirements were unde-sirable.
At this January 22, 1979 meeting, in response to a number of Mem-ber States' comments against provisions mandating or suggesting fail-safe design, the FRG representatives, without significant stated reasons, agreed without argument to delete the fail-safe provisions.
(2) Considerable discussion took place on the provisions of the guide con-cerning removal of signals from the safety system for non-safety system use.
(See Section 7.8.4 of 03 and 4.7 of IEEE Std 279.) After numerous proposed rewrites, the text was shortened slightly and the explicit recuire-ment for an isolation device was removed.
In my view, the revised text will also require an isolation device where the signals are electric in nature.
This point was brought up by Dr. Cobb who was substituting for Mr. Wolff, who was ill.
Neither Dr. Cobb nor or Dr. Fischer (FRG) had attended previous TRC mestings on 03.
Neither Dr. Cobb nor Dr. Fischer appeared to be familiar with the details of tha hardware practices in this area in either their country or ours. Afcer learning of the basic principles involved, they both argued strongly for stating the basic principles rather than the solution to the problem which has been to require use of isolation devices, at least in the U.S. and Canada.
Since the revised text will also necessitate use of isolation devices, although not explicitly, I feel we can live with the revisions as worked out by the TRC.
ATTENDEES OF TASK GROUP MEETING ON 0-8 Dr. E. C. Cobb Nuclear Power Co, UK Chairman TRC-Oesign for 0-8 Mr. C. Norpeta Power Research Institute Czechoslovakia Author Group Member Mr. J. L. Petrie Nuclear Installation Inspectorate, UK Author Group Membs.-
IEC Representative Mr. F. Reisch Swedish Nuclear Power Inspectorate Author Group Member Mr. S. K. Mehta Bhabha Atomic Research Centre, India TRC Member Mr. E. C. W nzinger NRC, USA e
TRC Member Mr. Z. Hatle IAEA i
1 l
i g
- +.
IAEA DISTRIBUTION
~ - ~ ~
E. 'X. Cornell (MNSB 6209)
J. D. Lafleur (MHS8 8502)
H. X. Shapar (MN88 9604)
'X. Pedersen (H,1015)
R. 'F. Fral ey (H-1016)
. W. Gamill (P-328A)
~
R. B. Minogue G. W. Rivenbark
- 1. C. Roberts W. M. Morrison
..S. Richardson J. A. Ngrberg J. L. Milhoan
',E. C. Wenzinger IAEA File B. H. Grier, Director
' Region I, USHRC 631 Park Avenue King of Prussia, PA 19406
\\
9 3
.o..%
d~.
-~
-..~
TRC-DESIGN MEETING ATTENDEES Mr. E. M. Yaremy, Canada, TRC Substitute Chairman Mr. J. Skrabal, Czechoslovakia Mr. G. Ganouna-Cohen, France Dr. J. Fischer, FRG Mr. G. Redondo, FRG' Mr. S. Mehta, India Mr. S. Ischizuka,' Japan Mr. E. C. Wenzinger, US Mr. G. Van Reyen, CEC Mr. I. Tiren, ISO Mr. P. Cormoult, IEC (France) 2