ML20207K158
| ML20207K158 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 01/02/1987 |
| From: | Watson R CAROLINA POWER & LIGHT CO. |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| HO-860396-(), HO-860396-(0), NUDOCS 8701090332 | |
| Download: ML20207K158 (3) | |
Text
{{#Wiki_filter:r_ Drh8 x CP&L Ca<otina Power & Light Company 07 J AN 6 A 8 :,1 3 = =. ~.. - s s HARRIS NUCLEAR PROJECT JAN 2 1937 File Number: SHF/10-14030 Letter Number: H0-860396 (0) Dr. J. Nelson Grace United States Nuclear Regulatory Commission Region II 101 Marietta Street, Northwest (Suite 2900) Atlanta, Georgia 30323 HARRIS NUCLEAR PROJECT UNIT 1 DOCKET No. 50-400 LICENSE NO. NPF-53 NRC 30 DAY SPECIAL REPORT In accordance with Technical Specifications 3.4.9.4 and 6.9.2 for the Harris Nuclear + Plant, Unit No. 1, Carolina Power & Light herewith submits this Special Report. This Special Report contains information on the Actuation of the Low Temperature Over Pressure Protection System, on December 3, 1986. Very truly yours, W / . A. Watson M Vice President Harris Nuclear Project RAW /RS/sdg Enclosure cc: NRC Document Control Desk 8701090332 870102 PDR ADOCK 05000400 S PDR MEM/HO-8603960/ PACE 1/OSl i r io mi
PORV ACTUATION SPECIAL REPORT
Background:
s s On December 3, 1986 at 2322, the plant experienced a low-temperature, over pressurization event while conducting fill and venting operations of the Reactor Coolant System (RCS). The cause of the event was personnel error. As required by Technical Specification 3.4.9.4, Action Statement c, the over pressurization was evaluated and the conclusion reached that design parameters were not exceeded. The cause of the event was personnel error, aggravated by a procedural deficiency and equipment problems. The plant was in Mode 5 conducting fill and vent operations in preparation for running reactor coolant pumps. Reactor Coolant System pressure was being displayed by the operators using narrow range pressure transmitter PT-402 on the trend plot CRT. The operators had also been experiencing some erratic operation of pressure control valve PCV-145 which controls RCS under these conditions. Description of Event: At approximately 1700 on December 3,1986, procedure MST-IO322 for calibration of RVLIS level instruments was requested for start, including the closing of isolation valves IRC-980 through 1RC-983. The procedure prerequisite data sheet indicated to the Shift Foreman that only level instruments would be affected. No mention was made of RCS pressure PT-402 and PT-403 which were also isolated. After the isolation valves were closed, apparently some leakage occurred because main control board (MCB) pressure indicators PI-402.1, PI-403.1 and PI-402.A appeared to be tracking RCS pressure up to the time of the incident. On the next shift, at about 2300, RCS pressure was being increased from 70 psig to 325-350 psig with the plant solid as required by procedure. Unaware that the PT's were isolated, PI-402 was selected for trending on the plant computer since it is a narrow range indicator. The letdown pressure control valve, PCV-145, is used to maintain RCS pressure in this condition and had been noted by the operators to be operating erratically at times. Pressure stabilized at 344 psig at 2310 with PCV-145 in automatic. Around 2315, the wide range pressure indicator PI-402.1, the narrow range pressure indicator PI-402.A, the CRT trend plot of PI-402, plus the PI-402 narrow range recorder indicated rapid drop in pressure to about 60 psig, which was attributed to depressurizing the sensing line for RVLIS. The operator noted that letdown flow was high and attributed the drop in pressure to erratic PCV-145 operation, i.e., letting down too much flow. Although there.were several other indications of RCS pressure and letdown pressure, the control room personnel concentrated on the trend plot from the computer and their MCB indicators. They did not check all available indication. In order to restore pressure, the operator attempted to increase pressure by raising PCV-145 MEM/HO-8603960/PAGE 1/OSI
's ..\\- setpoint. When the demand setpoint in auto was at 100 percent calling for the valve to be shut, the operator noted the valve was still 25 percent open. Feeling the valve was not responding properly, the operator then took the val've to manual and shut it further. At 2320, RCS pressure started to increase about 40 psig/ min. At 2322-30 PORV-445A opened at the low temperature - low pressure setpoint of 39G psig. Computer records indicate the valve opened a total of four times with about one minute between each cycle. This highest pressure recorded for the RCS was 392.1 psig, never reaching the second PORV setpoint. Approximately 56 gallons were discharged to the pressurizer relief tank (PRT). l The operator observed the PORV cycle and noted various annunciator alarms such as ALB-9 (Pressurizer PORV 445A Inst. Air /N Accum.) 2 and ALB-10 (High RCS pressure at Low Temperature). Looking at other indicators it was then realized that PI-402.1, PI-402.A, and PI-403.1 were incorrect. The operator then shif ted to PI-440 and PI-441 for indication. PCV-145 was adjusted to lower RCS pressure to less than 100 psig for evaluation. Analysis: Post analysis shows that RCS pressure reached 392.1 psig for an RCS temperature of 84*F. This was below the setpoint of the backup PORV at 400 psig. The subsequent Engineering Evaluation showed that the limiting pressure for this condition was 1750 psig, using the draft Appendix XX to ASME Section XI technique. Thus RCS pressure only reached 22.4 percent of its limit and was evaluated as not significant. Corrective Actions: 1. The operators were reinstructed to use all available indications on the main control board and not to focus attention on just one device. 2. Maintenance Surveillance Tests are to be reviewed to ensure adequate guidance is given to operators on the impact of running the procedure. Complete review of each MST will be completed prior to its next intended use. The review shall ensure all equipment is adequately identified. 3. A permanent program was implemented that will ensure all instrumentation affected by tests are marked in a manner recognized by operators. MEM/H0-8603960/PAGE 2/0S1 =.}}