ML17297A549
| ML17297A549 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 07/02/1981 |
| From: | Rosenthal J Office of Nuclear Reactor Regulation |
| To: | Rosa F Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8107090226 | |
| Download: ML17297A549 (10) | |
Text
REGULA Y INFORMATION DISTRIBUTIO SYSTEM (RIDS)
ACCESSION NBR! 81 0 FACIL>STN 50, 528 STN~50 529
, STN 50 530 AUTH~,NAME',
ROSENTHAL"iJ', E RE C I P ~ i>>!AMEI ROSA iF ~
7090226'.
DOC ~ DATE: 81/07/02 NOTARIZED; NO Palo-Verde Nuclear Stat(on<
Un)t ii Ar)zona Publ)
Palo Ve'rde Nuclear Station< Unit 2i Arizona Publ)
Palo Ve'rde Nuclear Station~
Unit 3i Arizona Publi AUTHOR AFF ILIA/ION Instrumentation',
Control Systems"Branch RECIPIENT AFFIL'IATION Instr umentation, L Contr ol Systems Branch DOCKET 0500 8
05000 29 05000530
SUBJECT:
- Discusses-8106'17 18 independent-design r eview in Phoeh~xpAZ
~
Industr y 8
NRC! are learning to integrate oper atingiemer gency test procedures 8 plant Tech Specs w/hardware'ISTRIBUTI N
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8>07090apg 8)07pp PDR ADOCK 05000528 53o PDR fiEhORANOUll FOR:
F. Rosa, Chief, Instrumentation 8 Control Syst ms Branch Division of Systems Integration FROt4:
SUBJECT:
J.
E. Rosenthal, Instrumentation
& Control Systems Branch Division of Systems Integration PALO VERDE IDR (INSTRUMENTATION AND CONTROL)
An "Independent" Design Review (IDR) of the Palo Verde instrument and
'ontrol systems was conducted by Arizona Public Service on June 17, 18, 1981 in Phoenix Arizona.
'I view the IDR as an effective means of communication between the applicant
- and staff.
The verbatum transcript provides a useful public record and relieves the staff of tedious note taking.
Presentations were made by Bechtel.
The IDR board was predominantly com-prised of APL staff who appeared to be well informed.
The APL staff has been working with Bechtel for some time now.
I believe the APL staff learned little, if any, from the formal presentations.
question and answer periods were worthwhile for APL and the NRC staff.
The theme of this IDR was a
demonstration of conformance with Commission regulations, and supporting
- guidance, rather than a review of the design per say.
Within this context, extended, structured meetings, attended by a well prepared NRC staff, and perhaps with a transcript, may be more effective, especially for the staff, than the more formal IDR process.
The CESSAR IDR (June 2, 3, 4) and the Palo Verde IDR will be followed by a joint meeting in July.
Me will also conduct drawing reviews and a site visit prior to our issuance of an SER.
The July meeting will attempt to fill gaps between the CESSAR and Palo Verde IDR's.
The'staff will issue a
meeting agenda following review. of the IDR transcripts.
Some preliminary observations seem appropriate:
(1)
The industry and the NRC staff is learning to integrate operating, emergency, and test procedures and plant technical specifications with the hardware.
This link was considered throughout the Palo Verde IDR.
Failure to as extensively consider this link was a
shortcoming of the CESSAR IDR.
Contact:
J. Rosenthal X39434
t I
(2)
The CESSAR IDR covered CE's scope of supply.
The Palo Yerde IDR tended to cover those systems entire1y within Bechtel 's scope of supply.
Our fo1thcoming meetings and drawing reviews, especially the drawing reviews, wi) 1 attempt to bridge the gap (for example between ESF actu-ation relay contacts, CE scope, and actuated
- device, Bechtel scope.)
Containment pressure and temperature control following a design basis event (LOCA, SLB) is to be accomplished using the Containment Spray System.
bo credit is taI;en for the Containment (Fan/Chiller) Cooling System.
The containment normal ACU fans are normally powered from 1E buses.
and load shed upon generation of a Safety Injection Actuation Signal.
Upon system level actuation signal reset, the ACV fans are to be automatically reinstated on lE buses.
Such automatic reinstatement is not in concert with the guidance of IE Bulletin 80-06.
(4)
It may be prudent to modify the system such that automatic rein-statement of 'this system on 1E buses does not occur, and require that the operator confirm availability of the system pr ior to manual loading on the 1E buses.
Fai1ure to reinstate normal containment cooling may result in containment spray actuation.
An action clearly undesirable from a commercial/plant availability standpoint.
It would appear that this system is not considered essential with-in the narrow context of confirming the adequate sizing of emergency safety features, containment spray, to mitigate design 'basis events, but is considered essential within the broader context of plant oper-
- ations, including emergency, procedures.
The system may be acceptable as designed, or may require some modifica-tion, or may require upgrade to a fully qualified safety system.
A con-sistent interdisciplinary rationale seems in order.
CSB and DHFS should review these design aspects (CSB will review chiller isolation as part of its normal review effort}.
Bechtel supplied system for generation of Containment Purge Isolation Actuation Signal, Fuel Building Essential Yentilation Actuation Signal, Control Room Ventilation Isolation Actuation. Signal, and Control Room Essentia]
Filtration Actuation Signal, are 1 of 2 logic,systems.
Bypass of one actuation channel is permitted.
Interlocks exist to prevent isolation of both channels.
Bechtel presented its rationale to per-mit unlimited operation with one channel in bypass.
Incorporation of some'time limit in the plant technical specifications may be in order.
AEB should review this aspect of the design.
. *Air Cooling Unit.
I I
1 (5)
(6)
(7)
(s)
The safety equipment status system as described meets the intent of R.
G. 1.47, Bypassed and Inoperable Status Indication for Huclear Power Plant Safety Systems, and appears to meet R.
G. 1.75, Physical Independence of Electric Systems.
The indicating panels were designed some time ago and may not meet today's perceived needs.
Disp1ay formats should be reviewed by HFEB.
Several other systems change state after ESF actuation signal reset.
Further justification of the current design is needed.
The operator will monitor compliance with linear heat generation rate and departure from nucleate boiling ratio limiting conditions for oper-ation using the Core Operating Limit Supervisory System (COLSS).
COLSS is executed on the plant computer.
COLSS is classified as a "control system not required for safety."
s l COLSS software is provided by CE.
A verification and validation pro-gram (including software integrity protection) is needed at APS.
The extent of this program should be consistent with its function, maintenance of the plant within LCO's.
The program need not be as extensive as re-quired f'r the CPC's which are part of the RPS.
APS is to describe their program.
APS was informed that the control system is to be modified to permit achievement of cold shutdown from the control room consistent with RSB BTP 5.1.
The IDR board has taken this matter as an open item (as are several of the other items discussed) and will respond.
Instrumentation and controls located at the remote shutdown panels, ESF Switchgear and from local stations which would be required to maintain the plant at hot shutdown and bring the plant to cold shutdown were enumerated at the IDR meeting.
Instrumentation and controls on the remote shutdown panel and in the ESF switchgear
- area, appear to be of sufficient extent and redundancy to maintain the plant at hot shutdown.
The ESF switchgear area is adjacent to the remote shutdown panels.
The system appears based on our review to-date, to be designed in conformance with R.
G. 1.75 and GDC 19.
In order to achieve cold shutdown from outside the control room, local controls must be employed.
DHF should review the suitability of the physical location',of these controls, vis a Vis, plant procedures.
Without access to plant procedures, ICSB cannot confirm that instrumenta-tion and controls located on the remote shutdown panels are of sufficient extent.
These procedures are yet to be written.
Since the procedures will reflect the availability of existing equipment, the classical chicken and the egg syndrome is at work.
I will request that O'S inform ICSB of changes to the remote shutdown panel which may be re-quired as procedures evolve post SER.
(10)
Manual ESF override on the equipment level and the effect of system level ESF reset on equipment override is indicated to the operator by red, white, green, and absence of backlighting of ESF device switches.
DHFS should review the suitability of this scheme.
(11)
Palo Yerde does not employ an active containment vacuum relief system.
It is my understanding that it is APS's intent to operate with 8" containment vent valves open.
CSB should re-view this aspect.
Should continuous operation with open vent valves be deemed unacceptable, an active containment vacuum relief system, such aC employed at Waterford-3, may be necessary.
(12)
Inadequate core cooling instrumentation has not been designed.
APS will comply with the requirements of HUREG-0737.
It is 'not clear to me whether these items should be considered SER open items or SER confirmatory items.
(13)
Control system failure studies are "in review" and were not dis-cussed at the IDR.
I believe some discussion of the intended scope of these studies, prior to the SER,is appropriate.
cc:
H. Denton R. Mattson P.
Check M. Srinivasan V. Moore.
T. Speis H. Butler R. Houston Dunning V. Mech (ANL)
N. Kondic J.
Kerrigan C. Grimes
.,-,-g,-:-'
J.
E. Rosenthal Instrumentation 8 Control Systems Branch Division of Systems Integration
I