ML19308A858
| ML19308A858 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 05/18/1973 |
| From: | DUKE POWER CO. |
| To: | |
| Shared Package | |
| ML19308A856 | List: |
| References | |
| NUDOCS 7912120649 | |
| Download: ML19308A858 (3) | |
Text
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j OCONEE UNIT I O
REACTOR BurtDINc SPRAT PUMPS 1NOPERABtE DURING REACTOR OPERATION ABNORMAL OCCURRENCE REPORT INIkODUCTION Oconee Unit 1 Technical Specification 3.3.1 requires that two reactor building seray pumps and their associate spray nozzle headers be operable before the reactor is made critical. On May 8, 1973, it was found that the reactor building spray pumps had been rendered inoperable by jacking out the electrical breakers on the pump motors. During the period that the reactor building spray pump motors were inoperable, the reactor was made critical and operated at power levels from 0% to 15% full power. Technical Specification 1.8 defines an abnormal occurrence as the occurrence of any plant condition which exceeds a limiting condition for operation as established in the Technical Specifications.
The failure to have two reactor building spray pumps operable before the reactor was made critical is classified as an abnormal occurrence, and is reported pursuant to Technical Specification 6.6.2.1. The Directorate of Regulatory Operations, Region II, was notified on May 9, 1973.
DESCRIPTION OF THE INCIDENT At approximately 11:15 a.m. on May 8, 1973, during the performance of Instrument Procedures IP/0/A/310/12D, "RB Spray Channel 7 On-Line Test," and IP/0/A/210/13D, "RB Spray Channel 8 On-Line Test," it was found that the Unit I reactor building spray pump motors "A" and "B" would not operate.
Consequently, it was determined that the electrical breakers on the pump motors were jacked out.
Thh control operator, shift supervisor, operating engineer, and station superintendent were informed of the incident.
The breakers were immediately jacked 'n atd the in-strument tests were completed.
A review of the tag logs, Electrical Interlock end Bypass Log, Shift Supervisor's Log, and Reactor Operator's Log revealed no documentation that the reactor building spray pump motors were jacked out. Upon further investigation, it was discovered that Operating Procedure OP/1/A/1102/10 " Controlling Procedure for Unit Shutdown,"
was partially performed on May 2, 1973, during a cooldown of Unit 1.
Step 3.2.42 requires the jacking out of the reactor building spray pump breakers.
On May 3, 1973, OP/1/A/1102/01, " Controlling Procedure for Unit Startup," was initiated to bring the unit to the required power level for continuation of power escalation 2)gg
testing. Step 14.a of the precritical checklist portion of OP/1/A/1102/01 requires verification that the two reactor building spray pumps are operable.
This step was not signed off.
On May 5,1973, another precritical check was initiated following a reactor trip.
This time, Step 14.a of the checklist was initialed by a utility operator.
Instead of checking the operability of the pumps, the utility operator asked the control operator if the reactor building spray system was operable, and was informed that the system had been tested several days before, and the control operator thought it was still in an operable condition. The control operator did not know the breakers had been jacked oat.
CONCLUSIONS From the results of the investigation, it is concluded that Unit 1 reactor building spray system was inoperable from approxmately 1:30 p.m. on May 2, 1973, until approximately 11:30 a.m. on May 8, 1973, due to the pump motor breakers being jacked out.
During this period, the reactor was critical for approximately 82 hours9.490741e-4 days <br />0.0228 hours <br />1.35582e-4 weeks <br />3.1201e-5 months <br /> at power levels less than 15% full power.
This incident resulted from failure to follow written procedures.
Paragraph 1.0 of OP/1/A/1102/01, " Controlling Procedure for Unit Startup," states that "All steps must be signed off to avoid possible omission." Contrary to this require-ment, all steps were not signed off.
SAFETY IMPLICATIONS The reactor building spray system is designed to provide building atmosphere cooling to limit post-cccident building pressure to less than the design value and to reduce it to nearly atmospheric pressure.
This system is completely independent of the reactor building cooling system, which provides additional building cooling.
Section 14.2.2.3.5 of the Oconee Final Safety Analysis Report discusses the reactor building pressure response for the loss-of-coolant accident.
Figure 14-56 shows that the reactor building design pressure is not exceeded for the worst-case accident with reactor building cooling provided by three building air coolers. Additional analyses (FSAR Supplement 13) have shown that the building design pressure will not be exceeded even if all sprays and coolers are inoperable.
Therefore, it can be concluded that there are no significant safety implications associated with this occurrence..
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CORRECTIVE ACTION TO PREVENT RECURRENCE As a result of this incident, the following corrective action will be taken:
- 1) All operating procedures will be reviewed to ensure that they require the tagging of any safety related system or component which is disabled.
- 2) Additioval emphasis is being given to operating personnel regarding the necessity for properly performing all steps of an operating procedure.
- 3) The controlling procedure for plant startup will include a step which requires the shift supervisc: review the pre-heatup and pre-critical checklists before giving permission to begin reactor startup.
Implementation of these corrective actions has already begun, and it is anti-cipated they will be complete in the very near future.
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