ML20235E735
| ML20235E735 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 07/01/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20235E722 | List: |
| References | |
| RTR-REGGD-01.045, RTR-REGGD-1.045 NUDOCS 8707130067 | |
| Download: ML20235E735 (2) | |
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION EVALUATION OF RCS LEAK DETECTION FACILITv OPERATING LICENSE N0. OPR-51 ARKANSAS POWER AND LIGHT COMPANY ARKANSAS NUCLEAR ONE, UNIT N0. 1 DOCKET NO. 50-313 INTRODUCTION By letter dated October 14, 1986 (ICAN108607), Arkansas Power and Light Company (the licensee) submitted a comparison of the Reactor Coolant System (RCS) leakage detection systems installed at Arkansas Nuclear One, Unit 1 (ANO-1) to the individual items contained in Regulatory Guide (RG) 1.45.
In response to a request by the staff, additional information was provided in licensee letter of March 20, 1987 (ICAN038704).
BACKGROUND On May 12, 1986 a revision was made to General Design Criterion 4 (GDC-4) which stated that "the dynamic effects associated with postulated pipe ruptures of primary coolant loop piping in pressurized water reactors may be excluded from the design basis when analyses demonstrate the probability of rupturing such piping is extremely low under design basis conditions." The staff reviewed the B&W Owners Group reports BAW-1847, Rev.1, and BAW-1889P which apply " leak-before-break" technology as an alternative to designing against dynamic loads associated with postulated ruptures primary coolant loop piping.
The staff evaluation concluded that an acceptable technical basis was provided to elimi-nate, as a design basis, the dynamic efforts of large ruptures in the primary i
coolant system loops of ANO-1.
The evaluation was sent to the licensee by letter dated February 18, 1986.
The letter also stated that information should be submitted to demonstrate that the leakage systems installed at ANO-1 comply with RG 1.45.
That information was submitted via licensee letters of October 14, 1986 and March 20, 1987.
EVALUATION The regulatory position of RG 1.45 states that RCS leakage should be identi-fiable to the extent practical. The licensee has demonstrated that the leak RCS detection systems are designed to meet this position by conforming to the following criteria specified in RG 1.45:
1.
Leaks frcm identified and unidentified sources are monitored separately.
2.
Leaks from unidentified sources be monitored with an accuracy greater than one gallon per minute.
3.
Three separate detection methods are n ed by the RCS leak detection system-sump level measurement, inventory balance and radiation monitoring (both airborne particulate and gaseous radioactivity).
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4.
Intersystem leakage is monitored by several different methods including radioactivity monitoring.
5.
Each RCS leak detection system employed for determination of unidentified leakages is sufficiently sensitive to detect leaking of one gallen per minute in less than one hour.
6.
The RCS leak detection means for airborne particulate radiation monitoring and one of the redundant reactor building sump level indicators are quali-fied to the response spectra of the safe shutdown earthquake.
The makeup I
tank level indicator, although not specifically seismically qualified, will remain operable following minor seismic events.
7.
The redundant reactor building sump level indicator, airborne particulate and gaseous radioactivity monitors and the make up tank level indicator can be read in the control room.
Also, alarms for high radioactivity and low levels in the makeup tank are provided different types of readings which could not be rigorously converted into common leakage equivalent, the measurements provide a good estimate of the magnitude of leakage.
By comparing the readings from different instruments, the operator can gain sufficient information on the type and magnitude of the leakage.
8.
There are provisions for testing operability and calibration of the RCS leak detection system.
The procedures for testing the system are included in the plant technical specifications.
9.
The plant technical specifications include the limiting conditions for iden-tified and unidentified leakage and address the availability of various types of instruments to assure proper detection of leaks at all times.
CONCl.USION Based on the considerations discussed above, the staff concludes that the RCS leak detection system meets the guidelines of RG 1.45 and is, therefore, able to detect and measure leakage with sufficient degree of accuracy to allow the
" leak-before-break technology to be satisfactorily used in analyzing primary coolant loop piping integrity.
Dated:
July 1,1987 Principal Contributor:
K. Parczewski
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