ML20245K867
| ML20245K867 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 04/25/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20245K863 | List: |
| References | |
| NUDOCS 8905050196 | |
| Download: ML20245K867 (4) | |
Text
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o UN!TED STATES E.g j
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,j WASHINGTON, D. C. 20555
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SAFETY. EVALUATION BY-TIJE OFFICE.0F NUCLEAR. REACTOR. REGULATION RELATED.TO. AMENDMENT NO. 93 TO FACILITY.0PERATING LICENSE.NO..NPF.6 ARKANSAS POWER AND. LIGHT.CONPANY ARKANSAS NUCLEAR ONE.. UNIT.NO.'2 DOCKET N0. 50-368 INTRODUCTION _N By letter duted December 12, 1986, Arkansas Power and Light Company (AP&L or the licensee) requested amendments to the Technical Specifications (TSs) appended to Facility Operating License No. NPF-6 for Arkansas Nuclear One,(Unit 2 (Ah0-2).
the requirement to complete verification tests for the Combustion Engineering Systems Excursion Code (CESEC).
The CESEC code has been developed by CE for analysis of normal and abnoresl (non-LOCA) occurrences in pressurized water reactor nuclear steam supply systems (NSSS). The program is used in licensing safety analyses and for best (stimate predictions of the dynamic response of the NSSS.
The CESEC code was utilized for the FSAR safety cnslyses for the ANO-2 plant.
Curing the operating license review for ANO-2 the staff reviewed the use of the CESEC code End surr.crized its findings in the portion cf the staff Safety Evaluation Report (SER) addressing the reactor coolant pump rotor seizure. The staff's SER finding were stated as follows:
"Our review of the C3EC code has progressed to the point that there is reasonable assurance-that the ar.a fysis results dependent on CESEC will not be appreciably altereo by sny methodology revision that may be required as a result of the staff's further review of the code. The parameters used as input to the applicant's analysis were reviewed and found to be suitably conservative. The results of the analysis showed that less than two percent of the fuel rods experienced departure from nucleate boiling. This assures that the fuel damage will be trinimal and that there will not be consequential loss of core cooling capability. The analysis shewed that the maximum pressure within the reactor coolant and nr.ain steam systems dio not exceed 110 percent of the design pressures."
The staff concludes that the plant design is acceptable with regard to possible seizure of a rotor of a reactor coolunt pump subject to the receipt of a ccuitment from the applicant to perferin confirmatory tests in support of the utilization of the CESEC and C0AST codes for the ANO-2 analyses. The staff will require that a description of the test program be submitted for review. Some of the verification tests are expected to be conducted in the b
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preoperational test program while others will be performed at a specified level of power. The staff will require, as a part of the commitment noted above, that the needed data and test results, obtained with proper instrunienta-tion, will be. submitted to the staff and will also be used by the applicant to confirni the pretest predictions by the CESEC and COAST codes. The results of our completed program will be applicable to ANO-2.
I Subsequent to the issuance of the SER further progress was made on this issue which was reported in Supplement 2 to the SER as follows:
"In our Safety Evaluation Report we stated that we had conpleted our review of the analysis of an instantaneous seizure of the re. actor coolar.t pump rotor, as evaluated by the computer codes CESEC and TORC. We concluded that the plant design, in this regard, is Lcceptable subject to (1) the receipt of a commitment form the applicant to perform confirmatory tests in support of the utilization of the CESEC code for the ANO-2 analyses, (2) receipt of a description cf tie test program, and (3) submittal to the staff of the actual test data and results obtained with proper instrumentation which confirnis pretest predictions l
n.ade by the CESEC code."
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The licenseo submitteo (1) a list of the tests to be performed in a letter i
dated March 13,1978,(2) the pretest predictions and a copy of the test procedure by the letter dated July 13, 1978, and (3) additional information on startup test results from another operating reactors startup testing programs by letter dated April 5,1978. We have addressed our requirements for the submittal.of the test data and results in a conditicn to the operating license.
This information will be obtained by the licensee during the startup and power ascension testing program when the tests are to be conducted.
We conclude that the licensee has acceptably satisfied our requireinnt for information, as stated in the Safety Evaluation Report, to be provided prict to the issuance of the operating license. We have addressed our requirements fc11owing the issuance of the operating license in a cordition to the ciertting license.
Issuance of Supplement 2 to the SER was concurrent with issuance of the operating license. The operating license included a condition as follows:
I "2.C.3(g) Verification of Transient Analysis Code The licensee shall cornplete tests to verify the use of the CESEC Code during the initial startup and power ascension testing program and submit the results for Commission review and approval.
The CESEC verification test results shall include an analysis of the uncertainties associated with the test instrun.entation and a demonstration that the test instrumentation was adequate for the intended purpose."
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, In response to this condition to the licensee conducted four types of tests during the initial Ah0-2 power ascension program. Thefourtestsincluded(1) turbine trip, (2) four pump loss of flow, (3) full length CEA drop, and (4) a past length CEA drop. The test results were reported by the licensee's letter dated March 27, 1981.
DISCUSSION Tne AN0-2 plant specific aspects of the tests relate to whether ur not the tests call into question the validity of the CESEC code as an analysis tool for conducting adequate safety analyses of the ANO-2 plant. As stated above, we l
concluded, with publishing of the SER, that reasonable assurance then existed "that the analysis results dependent on CESEC will not be appreciably altered by
, any methodology revision that may be required as a result of the staff's further reviews of the code". The purpose of the license condition was to require the licensee to develop and provide additional information, in the form of actual plant test results, in support of conclusions already reached by the licensee that CESEC it an appropriate analysis tool for ANO-2.
EVALUATION We have examined the li,ensee's submittal dated March 27, 1981 which reports the test results and ccmpares the results to the CESEC pretest predictions.
We find no.information in the submittal that required reperformance of safety analyses or any revision of the ANO-2 Technical Specifications (e.g., Safety Limits, Limiting Safety System Settings (LSSS), Limiting Conditions for Operation (LCO).
The license condition addresses the uncertainties associated with the test instrumentation and a demonstration that the test instrumentation was adequate for the intended purpose. The licensee stated that the test data was recorded with a PDP-11 minicomputer and the existing plant instrumentation. The existing plant instrumentation mentioned is part of the reactor protection system and engineered safety feature systems; therefore the uncertainties have been conservatively considered in the determination of the LSSS and LC0's. The test recording instrumentation is described in additional detail in the EpRI report NP 1708 "NSSS Transient Tests at ANO-2" prepared by Combustion Engineering, Inc., May 1981. This information indicates that instrumentation recorded the test date with an acceptable degree of accuracy.
On these bases reconfirm the conclusion maae in the SER that there is reasonable assurance that the analysis results dependent on CESEC will not be appreciably altered by any methodology revision that may be required as a result of the staff's further review of the code. We reconfirm our approval of the use of the ecde in current safety analyses which support operation of the AND-2 plant in accordance with the current Technical Specifications. Accordingly we find that all parts of the AN0-2 license condition have been satisfied and the condition may be deleted from the license.
4-j ENVIRONitENTAL CONSIDERATION The amendment involves a change in the installation or use of a facility 1
component locatad within the restricted area as defined in 10 CFR Part 20.
The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant
-increase in individual or cumulative occupational radiation exposures.
The Commission has previously issued ~a proposed finding that the amendment involves no significant hazards consideration and there has been no public comment on such finding. Accordingly..the amendment meets the eligibility criteria for' categorical exclusion set forth in 10 CFR Section 51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environmental impact statement or environ-nental assessment need be prepared in. connection with the issuance of the amendment.
CONCLUSION The staff has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in_ compliance with the Commission's regulations, and the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public..
Date:
April 25, 1989 Principal Contributors:
R. Martin J. Guttman C. Poslusny