ML20236T014
| ML20236T014 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 11/20/1987 |
| From: | Fay C WISCONSIN ELECTRIC POWER CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| CON-NRC-87-117 VPNPD-87-510, NUDOCS 8711300233 | |
| Download: ML20236T014 (4) | |
Text
{{#Wiki_filter:_ O Wisconsin Electnc eowen cournur 231 W. MICHIGAN.P.o BOX 2046, MILWAUKEE.WI53201 (414)277-2345 VPNPD-87-510 NRC-87-117 November 20, 1987 U. S. NUCLEAR REGULATORY COMMISSION Document Control Desk Washington, D.C. 20555 Gentlemen: DOCKET 50-301 SUSCEPTIBILITY TO HIGH CYCLE FATIGUE FAILURE OF STEAM GENERATOR TUBES POINT BEACH NUCLEAR PLANT, UNIT 2 The purpose of this letter is to document telephone conversations of November 17 and 18, 1987 between representatives of the Nuclear Regulatory Commission staff and Wisconsin Electric regarding primary-to-secondary leakage monitoring procedures for Point Beach Nuclear Plant described in our November 11, 1987 transmittal. During the November 17 conversation, we described the details of our leakage monitoring program. During the November 18 conver-sation, we were informed by the Commission staff that our primary-to-secondary leakage monitoring program is acceptable since it meets the criteria of being able to monitor a tube failure with leakage characteristics similar to that which occurred at North Anna and take appropriate actions prior to-rupture of the tube.- As requested, we are providing the details of our program in this letter. Our primary-to-secondary leakage monitoring program is described below and follows the logic flow diagram provided as Attachment 1. The items below are numbered to correspond to the circled numbers of Attachment 1. (1) Initial alert alarm setpoints for the unit specific air ejector monitor (RE-215),. unit specific steam generator blowdown monitor (RE-219), and combined air ejector monitor (RE-225) are established prior to unit power t generation. These alarm setpoints correspond to the radioactivity expected from a primary-to-secondary leak rate of 5 to 10 gallons per day (gpd) greater than the leak rate expected during initial power operation. i 8711300233B{og$$ot 0p[ PDR ADOCK 0 PDR P t
+ - ,y E 1 4E < S/ 1 November'20, 1987 /, Page 2 (2) During power escalation following a refueling shutdown, leak rates are evaluated using data from the continuous monitors, g> ) air ejector flow indicator, and radiochemistry analyses performed during periods of steady state operation. Based on these evaluations alarm setpoints are revised, if required. l (3) During full power operation, the leak rate monitoring program consists of continuous monitoring, periodic radio-chemistry analyses, and leak rate calculations. The radio-activity concentrations from the unit specific air ejector-monitor, combined air ejector monitor, and unit specific steam generator blowdown monitor are trended and reviewed each 8 hour shift. These provide direct indications of primary-to-secondary leakage. Data from the failed fuel monitor (RE-109) and the latest reactor coolant total gaseous activity are also trended and reviewed each shift to assess changes in the reactor coolant activity. The air ejector off gas flow rate is logged and reviewed each shift to assess changes in condenser air inleakage. Primary to secondary leak rates are calculated daily as a function of the air ejector radioactivity concentration, air ejector flow rate, and the most recent reactor coolant gaseous activity. During periods of normal operation, the secondary j coolant gross radioactivity concentration is measured two times per week and reactor coolant total gaseous activity is measured three times per week for use in determining primary-to-secondary leak rate. (4) If an alert alarm is received from the unit air ejector monitor or if the calculations of primary-to-secondary leak rate indicate that the leak rate is increasing, the indi-cated change is evaluated by other means. These may include, but are not limited to, reviewing the trends of the other continuous monitors, reviewing changes in operating condi-l tions, or performance of radiochemistry analyses to allow independent calculation of the primary-to-secondary leak I l rate. The alert alarm setpoint for the unit air ejector monitor is increased to a value which corresponds to an i increase in the leak rate of about 15 gpd. (5) If evaluation shows that the primary-to-secondary leak rate is greater than 40 gpd or the leak rate has increased by more than 15 gpd and continues to increase, an evaluation of the leak rate will be performed at least every four hours. If the leak rate is stable, the alert alarm setpoint for the unit air ejector monitor is increased to a value q which corresponds to an increase in the leak rate of about 15 gpd. i (6) If the leak rate exceeds 100 gpd, an evaluation of the I need to reduce power or shut down will be performed. This ) I l L-_________-__
K 4 f. j L.< W U/ (N [ ( f y I k@mber 20, 1987 1 \\ s Wage 3 \\y \\ ig.. y i, i'4 evalubticn w'if.1 include the leak rate history and the rate (/ ' 'i of change 'of" die leak rate. This evaluation will provide (' '? adequnty time -to reduce power or! hdt down should a tube fatighe failure be in progress. 'E I /, ,r 9 (7) The unit / specific air ejector moniNor (RE-215) is the most sensitive" to primary-to-secondary leak rate. Therefore, l' l g(' if RW-215 is out-of-service,. daily secondary coolant and air ejector off gas radioactivity. analyses will be performed. (T, The first samples of the air ejector off gas and secondary 1 coolant will be performed within 4 hours of RE-215 being . l,. \\' declared out-of-service. These analyses are staggered about 0( 12 hours apart. Trending and review of other parameters will continue as described in (3), above. .Q Training on the North Anna tube fai10re and the basis for our primary-to-secondary leak rate. monitoring program is being ccAducted during the trai/.ing cype which began November 16 and !?is expected to be complet4id in This ' training will include all licen,ah roximately five weeks. se,d reactor operators. ,) The leak detection progbam described above is being applied to e both Units 1 and 2 7c provide, for consistent operating procedures for the two units, j Please contev:j', I us if you hkve any questions regarding(this J [ information. very trul1y. yo).1:s, } k' k / '4 [hJ I 4 , g \\' / < 1 s C. W. Fay f Vice President -{j Nuclear Power .N 't i i s Copy to NRC Regional Administrator, Region III NRC Resident Inspector d i l l
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- ATTA(HENT 1 -
PODiT SEACH WCLEAR PLAffi PRIMARY TO g g CETECTION ESTABLIW4 INITIAL ALERT ALAftt h EvggGN .rEr.Ta -.EAmRT/ SETPL 8 It au MONIT015 A@ QEMISTRY ANALYSES vN 12 DF NB7 LEAKRATE? T / SECONDARY COOLANT RAD GA8 EVEH H ) N \\ NO LEAK RATE >400PD NO / P/5 YES l 2 m LEAK NO RATE STABLE? >100 SPD? IMGE *AED leafs TE OR EVALUATION 8441TDOWN I i L _.}}