ML20056A036
| ML20056A036 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 06/15/1990 |
| From: | Kovach T COMMONWEALTH EDISON CO. |
| To: | Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| NUDOCS 9008030109 | |
| Download: ML20056A036 (5) | |
Text
,
Commonwealth Edison
)
} 1400 Opus Place gc0 l
- / Do;; nets Crove, Illinois 60$15 e
z
.\\
%.J June 15, 1990 Mr. A. Bert Davis Regional Adsninistrator U. S. Nuclear Regulatory Commission Region III 799 Roosevelt Roet Glen Ellyn, Illinois 6M37
Subject:
Braidwood Station Units 1 and 2 P.esponse to Inspection Reports Nos.
50-456/90-010 and 50-457/90-011 NRC_Ilo c kei_No a,_5 milan d__iD -h51 References (a)
W. D. Shafer's letter to C. Reed dated May 17, 1990 Dear Mr. Davist Reference (a) provided the results of the inspection conducted by Messrs. T. M. Tongue, T. E. Taylor, J. A. Ilopkins and J. F. Ilarold from April 18 through April 28, 1990 of activities at Braidwood Station.
Reference (a) in:licated that certain activities appeared to be in violation of NRC requirements. The Commonwealth Edison Company response to the Hotice of Violation is provided in the Enclosure.
If you have any questions regarding this response, please direct them to this office.
[,
w T.
Kovach Nuclear Licensing Manager Enclosure cct NRC Resident Inspector - Braldwood NRC Document Control Desk 9008030109 900615 g
PDR ADOCK 05000456 VOt Q
\\
SCit/sc1:1088T 2 g
1
ENCLOSURE C0tNONWEALTH EDISON COMPANY'S RESPONSE TO INSPECTION REPORT li0auhML20010_anLMlLo0011 VIOLATION:
(457/90011-01)
Technical Specificat'
- 3.6.2.2.b requires that the containment spray chemical addition e t er. ' hall be operable in Modes 1, 2, 3, and 4, with s
two spray additiv educt s each capable of adding NaCll (sodium hydroxide) soluti i (v" the spray additive tank to a containment system requirement states:
"With the Spray Additive pump flow. The ac <
System inoperable, store the system to OPERABLE status within seven days or be in at least il0T STANDBY within the next six hourst restore the Cpray Additive System to OPERABLE status within the next 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> or be i
in COLD SilVTDOWN within the f ol',owing 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />."
Technical Specification 4.6.2.2 statcal "The Spray Additive Dystem shall be OPERABLE:
.d. at least once per five years by verifying each water ilow rate equivalent to 55 (+5, -0) gallons per minute (gpm) ior the 307. NaOH from the eductor test connections in the Spray Additive System." Trains A and B must show 68 (46 -0) gpm each.
Contrary to the above, on October 19, 1989. Unit 2, Train B of Containment Spray Chemical Additive System was identifled as inoperable when the spray additive throttle valve 2CS021B was found fully open vice throttled. This resulted in an analyzed flow rate of 115 gpm versus 68
(+6, -0) spm as required. This condition was promptly corrected upon identification and had existed at least since March 13, 1989 (in excess of ten months) when the valve had been mispositioned f rom an outage.
RESPONSE
Commonwenith Edison (Edison) acknowledges that the mispositioning of the containment spray throttle valve (2CS021B) prevented the containment spray system from meeting the requirements of technical specification 3.6.2.2.
A review of this event performed by Sargent and Lundy (S&L) was forwarded to NRR for review and validation. As stated in the inspection report:
"The NRR reviewer independently verifled S&L's calculation...
In addition, the NRR review recalculated the rates of corrosion of metals, such as aluminum, r.inc, etc. to evaluate the hydrogen buildup in the containment. The NRR reviewer found that Edison's assessment was overly conservative in that the corrosion rates were much less than stated by the S&L assessment, and hydrogen buildup weuld be considerably less than first thought. NRR also concurred with the resident inspector in that the Equipment Qualification impact would not have been as serious as initially thought and as stated in the previous inspection reports."
Edison believes that the root cause for this m nt was a programmatic deficiency. The existing program for locked throttle valves did not provide specific information at the point of manipulation identifying that the valve was required to be in the throttled position.
i Scil /sc1:10887:3
1
+
s 2
Edison's review of this event determined that there had been no negative impact on the health and safety of the public.
CORRECTIVE ACTION TAKEN AND RESULTS ACl!IEVED:
The 2CS021b valve was returned to the correct throttle position and locked in that position.
3 In order to ensure other Unit 2 valves were locked in their proper position, the position of all " accessible" locked valves on the 18-month Locked Valve Surveillance, 2BwoS XLE-R1, were position verified. All safety-related locked components were found in the correct position.
On May 7, 1990, at the conclusion of Unit 2 refuel outage, 2Bw0S XLE-R1 was again performed and all Unit 2 locked valves were position verified. For Unit 1 the 18-month Locked Valve Surveillance, IBw0S XLE-R1, was completed prior to the unit returning to operation following its refueling outage.
i i
CORRECTIVE ACTION TAKEN TO AVOID FUdTHER VIOLATION:
The personnel involved in this event were included and participated in a Braidwood Station Error Evaluation Presentation in order to identify the root and contributing causes of the event.
Based on the conclusions of this presentation, the following corrective actions are being initiated to prevent recurrence.
1.
The Out of Service Form (BwAP 330-1T4) was modified to require the "as found" position to be entered on the outage form when the component is removed from service. Also, the Out of Service computer program (Outage Editor) prints a special note to record the throttle position for throttled valves that are used as isolation points.
2.
The Out of Service Program Procedure (BwAP 330-1, " Station Equipment Out of Service Procedure") was revised to provide additional guidance concerning the use of throttle valves as isolation points for removing equipment from service.
3.
In addition, valves that are required to be in the locked, throttled position will be provided with high visibility labels. These labels will identify that the valve is required to be locked in the throttled position. This action is complete for Unit 2 and will be completed for Unit 1 during the next refueling outage.
DATE OF FULL COMPLIANCE:
s Braidwood Station Procedure BwAP 330-1, " Station Equipment Out of Service l
Procedure," has been revised to provide additional guidance concerning l
throttle valves. The high visibility labeling for locked throttle valves for Unit I will be performed during the next refueling outage with an expected completion date of June 15, 1991.
SCH/sc1:1088T 4 l
3 VIOLATION:
(456/90010-01) 10 CFR 50 Appendix B Criteria V requires that activities affecting quality shall be prescribed by documented instructions, procedures, or drawings of a type appropriate to the circumstances and shall be accomplished in accordance with these instractions, procedures, or drawings.
Contrary to the above, on March 14, 1990, at approximately 11:31 a.m.,
an instrument mechanic f ailed to perform a surveillance procedure step during performance of Micro Electronic Surveillance and Calibration System (HESAC) surveillance Dw!S 3.1.1-338.
Failure to follow the surveillance procedure resulted in an inadvertent actuation of the 1RY456 pressurizer power operated relief valve (PORV), which reduced reactor coolant system pressure by 60 psi.
RESPONSE
Commonwealth Edison acknowledges that during the performance of Micro Electronic Surveillance and Calibration System (MESAC) surveillance Bw1S 3.1.1-338 a procedure step was not performed resulting in an inadvertent actuation of the IRY456 pressurizer power operated relief valve (PORV),
reducing reactor coolant pressure by approximately 60 pai.
There was no safety significance associated with this event. The instrumentation system weuld have functioned aa designed and prevented an unsafe condition had no operator action occurred upon discovery of the event.
CORRECTIVE ACTION TAKEN AND RESULTS ACHIEVED:
The Nuclear Station Operator (NS0), seeing various alarms and bistable status lights lit in the control room, determined that Channel 456 was reading high with all other pressurizer channels giving a normal, but decreasing pressure, and that the PORV 456 was open. The NSO then manually closed the 456 PORV along with its associated block valve and stabilized the plant. The PORV was open for only 11.23 seconds resulting in a reactor coolant system depressurizction of approximately 60 psi. The unit remained on line during thi event.
l l
CORRECTIVE ACTION TO AVOID FURTHER VIOLATION:
The personnel involved in this event were included and participated in a Braidwood Station Error Evaluation Presentation in order to identify the root and contributing causes of the event.
Based on the conclusions of this presentation, the following corrective actions are being initiated to prevent recurrence.
1.
Appropriate MESAC Procedures will be revised to include the followingt a.
The omitted step will become the first step of the " Return to Service" section.
SCH/sc1:1088Tt5
FE l
4 t
4
]
b.
The omitted step will be identified as a "(D)" (signature required) step.
3 a
c.
The unplugging (disconnection) of the MESAC tester cable at the j
surveillance connector will become the second step of the " Return to Service" section and it will also be identified as a "(D)" step.
-Appropriate MESAC surveillances have been reviewed and 14 of 40 control / protection surveillances were identified as having the potential to cause an automatic control response if the same error was made during their performance. These 14 procedures were revised using the temporary procedure change method.
2.
A tailgate training session was held with all instrument maintenance personnel stressing self-checking /self-verification.
3.
The Training Coordinator reviewed the event and stressed the importance of performing the omitted step along with stressing attention to detail and procedural compliance with the Instrument Maintenance personnel on each shift following the event..
4.
The Training Coordinator conducted a one-on-one review of the event with each control system's technician to ensure that they understood the inter-relationship of the omitted step to the MESAC unit and to the instrument loop.
DATE OF FULL COMPL1ANCE:
The MESAC control / protection procedures are expected to be permanently revised by September 28, 1990.
i 1
SCit/sc1:1088T 6 l
a