ML20055G995
| ML20055G995 | |
| Person / Time | |
|---|---|
| Site: | General Atomics |
| Issue date: | 07/19/1990 |
| From: | Asmussen K GENERAL ATOMICS (FORMERLY GA TECHNOLOGIES, INC./GENER |
| To: | Weiss S Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20055G996 | List: |
| References | |
| 38-1579, NUDOCS 9007250030 | |
| Download: ML20055G995 (5) | |
Text
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&': '- l[*L-.o ; M July 19, 1990 ~
38-1579 Dr. Seymour H. Weiss, Director Non-Power Reactor, Decomnissioning and Environnental Project Directorate
-Division of Reactor Projects - III, IV, V
.and Special Projects o
Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Cmntission Washington, DC 20555
Subject:
Facility License No. R-38, Docket No. 50-89
References:
1.
Weiss, Seynour H.
(U.S. NRC) letter to Keith E. Asmussen (General Atcznics), "RE*.riew ' of Cmputerized Control System,"
Docket No. 50-89, dated June 12, 1990.
E
~2.
" Safety Evaluation under 10CFR50.59:- Microprocessor based:
Instrumentation and Control System for the General Atcxnics TRIGA Mark I Reactor," GA Document 'IRF-252 (Decerdser,1988).
3.
"NM1000 Software Functional Specification," GA Document E117-1001, GA Proprietary Information (March, 1989).
4.
"NM1000 Software Verification-Program," GA' Document E117-1002, GA Proprietary Information (March,1989).
5.
General Atcznics-Capany Policy Manual, Policy No.1201.3.
n 6.
"TRIGA CSC Review Meeting on the Mark I Camputerized Control System: 10CFRSO.59 Application,"' GA Internal Memorandum No.
CED:693:AMB:88 (December 20, 1988) from TRIGA Criticality Safeguards Comnittee to R. A. Dean.
7.
Asmussen, Keith E. letter no. 38-1520 to U.S. NRC (Attention:
Mr. Alexander Adams) " Docket No. 50-89: Reactor Facility License No. R-38; Affidavit with Request for Protection of
-.ksw.
Proprietary Infonnation," dated February 22,-1990.-
N
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Dear Dr. Weiss:
1 28E b.g-
-This letter is in response to your letter (Ref. 1) summarizing the results of 8vr the NRC review of General Atomics' (GA) 10CFR50.59 safety analysis supporting SO :
.the installation of a microprocessor based instrumentation and control (I&C)
~ox,
system on GA's TRIGA Mark I research reactor (Ref. 2).
As required in your referenced letter, and pursuant to 10CFR50.90, appropriate changes to the 07 Mark I's Technical Specifications are being subnitted.
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Qv)~M,gw 0
pRIVE, SAN DIEGO. CA 92121 1194
/MRO 5o-PO. BOX 85608. SAN DIEGO, CA 92138-5608 (619) 455-3000 q
10955 JOHN JAY HOPKINS I
y
y Dr. Seynour & Weiss, Director -
July 19,-1990 Page 2 38-1579 While these changes are being subnitted to satisfy the requirments put forth in your letter, GA respectfully rejects your staff findings that the ccuputer-ized control system cannot be installed under 10CFR50.59.
We continue to stand by our findings, that the installation of this I&C system involves (i)-
no unreviewed safety questions, (ii) does not require any changes to the tech-nical specifications, and hence, (iii) meets the criteria for installation un-der application of 10CFR50.59.
GA's TRIGA Criticality Safeguards Comnittee (CSC) rigorously analyzed and reviewed the installation of the ccuputerized console and concluded that the use of the new system did not result in an un-reviewed safety question, for the following reasons:
1.-
All safety related scrams continue to use signals which are hardwired to their respective sensors.
2.
Added safeguards have been provided t.o cover operation with conputers.
The system is designed so tht if software failure conprcanises the ability of the couputer to present accura'e information to the operat6, r.nen hardwired displays - independent o1 the ccuputer displays -- are at all times available to the operator to detennine operating conditions.
3.
Watchdogs and self. checking. functions af the ccuputers and other enhance-ments provide a level of overall safety at least as high as, and probably
. greater than, the original analog contro s.
4.
The worst failure of the software which may cause the rapid uncontrolled withdrawal of all control rods produces no fuel' failure or other damage to the core.
5.
The design basis accident has not changed.
It is further noted that research reactor consoles have never been required to meet specific standards on environmental or seismic qualification, surge with-stand capability or electrcanagnetic interference referred to in your letter, nor is'it considered necessary for such consoles to neet such qualifications.
The modifications to the R-38 research reactor facility under question were reviewed by, anong others, the TRIGA CSC, to ensure that the proposed modifi-cations neet all criteria of 10CFR50.59.
The CSC is one of GA's " standing" safety ccmnittees established under ccupany policy (Ref. 5) and the Mark I's (R-38) Technical Specifications (Section 9.2).
The charter of the TRIGA CSC includes the review, evaluation and approval, as appropriate, of the nuclear and radiological aspects of pertinent modifications, experiments and. pro-cedures for the GA TRIGA reactors (R-38 and R-67). The ccumittee is appointed by, and reports to, a cognizant Senior Vice President who acts for the chief Executive Officer in this capacity. Ccmnittee members (presently ccuposed of
E Dr. Seymour H. Weiss, Director July 19, 1990 Pap 3 38-1579 seven expert % -i:t leart four are required) are knowledgeable in reactor opera-tions and safety, with education and experience in various fields directly applicable towards ensuring safe operation of the facility. This cmmittee is charged with the re @ ns!bility to review and approve - or disapprove - 10CFR
'50.59 applications: schnitted by the-facility, and has the expertise avaihble to do so.
If necesse n, it can, and does, call upon outside experts to assist in the decision-making progress.
Based on the documents subnitted, and :the results of a emprehensj.ve nulti-phase te-2 program approved by the Ccmnittee at each step and.:arried out by the facility on the new systan, the emntittee made its decision in Decenber,1988 (Ref. 6), that no, unreviewed safety o
questions existed with respect to the use of the microprocessor based I&C system, in a stand alone node, for the TRICA Mark I reactor.
It also found that no changes to the R-38 Technical Specifications were required to allow its use as a dedicated rer: tor control system.
The reactor safety ccanittee has reviewed your recent letter (Ref.1), and has reaffirned its original de-termination that use of the microprocessor based I&C system to operate the TRIGA Mark I reacto'. poses no unreviewed safety questions, and that it does not require any changes to the Technical Specification.
During the develognent and testing phases for the microprocessor based I&C system, the cvgnizant NRC project managers were kept fully inforned by GA of our det - N tion that a 50.59 approach could - and would - be used for the final installation of the cmputerized console. Discussions were held on sev-eral occasions _with NRC staff over a three year period before the actual in-sta11ation took place.
At no time was any contrary guidance or suggestions offered by NRC. One inportant observation pointed out to the NRC was the fact that on two prior occasions, control consoles (other than the original) were
-installed on CA's R-38 reactor by successfully applying the provisions of 16CFR50.59.
The first of these was as radical a r.parture frcan the original console'as the cmputerized control system appears to the NRC staff today.
The original R-38 console had electronic circuitry which relied only on hard vacuum tubes, while the first replacement used all transistorized circuitry, which raised in some circles at that time, the same questions of proven reliability and safety.
Nevertheless, the first and then the second replace-nent consoles were installed under 50.59 applications, after thorough scrutiny by the TRICA Criticality Safeguards Cmmittee.
The NRC found those applica-tions of ' 10CFR50.59 to be acceptable.
With this precedent and the very thorough, detailed review of the 50.59 application by the present Safety Cmutittee, CA determined and continues to maintain that no unreviewed safety questions exist, no changes to the R-38 7tchnical Specifications are neces-sary,.and therefore, the console installation under application of 10CFR50.59 was proper and justified.
Notwithstanding our findings, outlined above, that the cmputer console can be installed under application of 10CFR50.59, and CA's wish to avoid lengthy appeals processes to resolve the differences between CA's and your staff find-
t Dr.ISeynour H._ Weiss, Director July 19, 1990 Page 4 38-1579 ings, we request'a change to the R-38 Technical Specifications pursuant to the requirement in Reference 1 and under 10CFR50.90.
We request that you amend
- the R-38 Technical Specification to incorporate: (1) watchdog tiraer scram requirements (reactor. scram upon detection of error or failure in software nodules) - to the Mininum Required Safety' System Scrams - (Table I), and (ii)' to clarify the requirement that no nore than one of the required two independent power. level scram channels in Table I shall be a digital scram channel. - The-proposed changes to Table I are attached.
A copy of the safety evaluation' report-(SER) for installation of this console (Ref. 2) is enclosed to support these changes.- References 2 and 3, which support this. SER, are incorporated herein by reference. These two dccunents (Refs. 3 and 4) have been previously provided to NRC (Ref. 7) anct have been withheld from public disclosure pursu-ant.to-10CFR2.790.
Along with the above request. for change related to installation.of the can-puterized consolo, GA requests a change to the wording of section 5.2.3(a) and (b)cof the R-38 Technical Specifications.
This latter change - unrelated to-the first request - is to allow the use of portable ganma sensitive instru-ments other.than ion chambers, e.g. G-M detectors during repair to the radia-tion nonitoring systans.
This change in wording will give the-facility the flexibility to use other kinds of ganna sensitive instruments for both-reactors (R-38 and R-67) operated by GA.
The suggested wording - which parallels ~ the wording in the R-67 'Ibchnical Specifications - is as follars; changes _are highlighted in bold print:
L
-5.2.31
' The following monitoring systems shall be operable during reactor l.
operation or when work is done on or around the reactor core (Pur l
mriods-of time when maintananna ar repair to the radiation noni-l
' taring systems is king performed,' the intent of this PHinaH nn l.'
wi.11 be satisfied if the installed systan is replarwl as naadad with i-alternative or portable genna-sensitive instruments having their own i
L ale =a or which shall be kept undar visual observation.):
H
- a. An area radiation monitoring syntan capable of activating the j
evacuation alarm.
- b. A continuous monitoring systen for aihna radinactivity hav-ing a readout and audible alarm which can be heard in both the reactor and control roans. -
L We trust the above requests will meet with your approval. We would be happy to L
- provide additional information or answer any questions your staff may have on this request. 'Please contact the undersigned at (619)455-2823, or Dr. Junaid
- Razvi, Physicist-in-Charge of the TRIGA Reactors Facility, at (619)455-2441 if there are additional questions or nore information is needed.
.t e
,}
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e.;..
,:Dr.-Seymour H. Weiss, Director July 19, 1990 Page 5:
38-1579 s
A check in the amount'of $150 for the. adninistrative fee associated with this request is enclosed.
Finally, please note that Mr. Alexander Adams was con--
tacted by telephone on July 10, 1990 and an extension in time to subnit this Lletter,was requested and granted. It was mutually agreed to subnit this letter the week of July 16, 1990.
Very truly yours, Keith E; Asmussen, Ph.D.
Manager, Licensing, Safety'and Nuclear Cmpliance KEA:shs
Enclosures:
- 1) GA Check No. 2576896 for $150
- 2) Proposed revised Table I of R-38 'Ib::hnical Specifications-
-u 3). Safety Evaluation Report: Docmaent No. 'IRF-252 dated Deculer, 31988,- (Ref. 2) cc: Mr. Alexander Adams, U.S. NRC Headquarters-(w/o encl. 1 & 3)
Mr. John B. Martin, Administrator, U.S. NRC Region-V (w/o encl.1 & 3)-