ML20081H040
| ML20081H040 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 05/25/1991 |
| From: | Carroll G GEORGIANS AGAINST NUCLEAR ENERGY |
| To: | NRC |
| References | |
| CON-#291-11804 90-617-03-OLA, 90-617-3-OLA, OLA, NUDOCS 9106140081 | |
| Download: ML20081H040 (7) | |
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m.orgians Against Nuclear Encrcy P u h W4 Won E
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gg g 333 4Ch37 9> -6AT Greetings to the Nuclear Regulatory Commission from Georgians Against Nuclear Energy.
We have been discussing the A train emergency diesel generator at Nuclear Plant Vogtle (Unit 1) with Georgia Power Company, the NRC Staff and the Atomic Safety & Licensing Board since last July 1990.
We appreciate the concern and cooperation expressed by the Board, Staff and Georgia power during our informal process. We understand the Doard's limitations under the Nuclear Regulatcry Guide 10 CFR 2.714 t.o take our case to a conclusion that would give us relief.
We urge you to put aside the recent ruling, ASLDP No. 90-617-03-OLA Atomic Safety and Licensing Doard Memorandum and Order (Terminating Proceeding) on Cocket Nos. 50-424-OLA and 50-425-OLA. S ir.:e t he Boa rd's jurisdiction does not provide relief to our concerns, but is limited to weighing two flawed accident prevention measures, we appeal to you to accept our offering of assistance in the interest of solving the serious hazard posed by the problematic high jacket water temperature switches on the f our Vogtle emergency diesel generators.
Attached is a brief recap of our dialogue highlighting the most important issues in the record plus our conclusion that we urge you to take under serious review. The record contains several teams of material about the Calcon high jacket water temperature switches, accident circumstances, and cperator response time. It is time now to explore ways to fix the generator rather than whether the generator needs fixing.
In summary, we submit that choosing between untimely cperator response and unreliable switch technology is not a reasonahle choice. We hope that the enclosed submittal will convince you to mandate actual repair of the generator.
Our all-volunteer, citizen organization's procedural shortcomings notwithstanding, we appeal to you to consider this case on its meritt.
Respectfully submitted, f) avWfkVk
,G nn Carroll p Nepresentative for GANE Signed and dated in Decatur, Georgia May 25, 1991 9106140001 910525 06p)
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i GANE - May 25, 1991 - Page BACKGROU!TD Last July 1990 a Federal Register Notice alerted GANE to a request by Georgia Power to bypass on emergency starts the problematic high jacket water temperature switches which contributed to a station black-out at Vogtie in March of 1990.
Georgia Power plans to have an operator perform this essential trip function. The plan is intended to fulfill Nuclear Regulatory Guide 1.9 which requires that suf ficient operator reaction time be available f or bypassed trips. This requirement is not met.
The generator has a keep-warm electric heater on it w.11ch maintains the diesel temperature in a.145*F-170'F range. The automatic high jacket water temperature Calcon sensors alarm at 190'F and trip at 200'F when they are operating properly. When the trip is in a bypassed state the alarm is also I
bypassed. Georgia Power has an adopted procedure (VEGP 17035-1, Rev.
9, p.
- 98) to dispatch an sperator on emergency starts to see that the diesel is operating properly. Vogtle operators estimate they can travel from any point at Vogtle to the emergency diesel generator room in about three minutes (NRC Staff Comments, 1/11/91,.p.3, Correia affidavit).
In our April 22, 1991 Response to Applicant's Response to the Board's Memorandum and Order of January 22, 1991 we point out nonconservatisms in the calculations of fered by Georgia Power to establish the rate of.
temperature rise at no or limited NSCW flow which adjust Georgia Power's figure of approximately 10*F per minute rate of rise upward to 15'F per minute. Under such circumstances, coupled with an emergency start at the upper limit of the heater's control band 170*r or greater the operator would arrive three minutes later at 215'F or greater. This possibility of lack of operator control is one reason that we want the switches to be fixed.
If Georgia Power's figures of 10'F per minute rate of temperature rise are accurate, an operator leaving for the control room immediately if the generator starts at 170'F (the upper limit of the normal keep-warm range),
would theoretically arrive precisely three minutes and 30*F later, just as the generator reaches 2009r and must be tripped.
GANE observes that it will take some amount of time for the unit shift supervisor to find and assess p.
98 of VEGP 17035-1 and deliver the dispatch j '
order to the operator. Delay in giving the uispatch order would be exacerbated by the extremo and rare conditions of a Control Room Fire or a station black-out. The possibility that the dispatch order will not be given l
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1 GANE - May 25, 1991 - Page 3 inmediately, contributing to uncontrollable delay in operator response time is another reason we want the generator fixed.
There is a flaw in the p.
98 procedure in that the operator is sent to the diesel generator room but is not required to remain there. If accident conditions at Plant Vogtle become more extreme and the operator has already left the diesel room, if the cooling water failure occurs later, initial warning would not be given to the control room until 190*F. While we work on
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repairing the generator, this procedure must be made clear so that the operator will stay with the diesel generators until their service is no longer required.
Miscommunication and confusion are common under accident conditions, especially during a station black-out. During the March 20, 1990 accident several instances of miscommunication are documented (NUREG 1410 Loss of Vital AC Power and the Residual Heat Removal System During Mid-Loop Cperations at Vogtle Unit 1 March 20, 1990, pp.
1-4, 2-7, 3-25, 5-14).
Besides the previously mentioned possibility of delayed operator reaction time, a miscommunication on dispatch of the diesel generator operator could result in this crucial piece of equipment being disabled Guo to lack of automatic overheat protection. The possibility of miscommunication is another reason we urge you to have the switch fixed.
NUREG 1410, 10.4.1 Pneumatic Control / Trip Sensor Reliability concludes the sensors on the high jacket water temperature trip f ailed and tripped spuriously because of foreign matter on the sensor tips. The high jacket water temperature trip has suffered chronic calibration drift which is blamed on air leaks. The high jacket water temperature trip is a sensor which is connected to a pneumatic logic board which is based on air pressure. The connecting air lines have been left intact but valved out.
Should the air pressure drop too much within the system due to fitting or valve leaks, the P-3 interlock will actuat'e and cause the trips on the system to be at a pre-tripped setpoint at start-up. The high jacket water temperature trip has spotlighted the inherent weakness of the pneumatic logic. The low lube oil pressure trip has failed repeatedly from the same sort of moisture or contamination which has plagued the bypassed high jacket water temperature trip (NUREG 1410, Appendix I, Sec. 3, Vogtle Experience with Calcon Sensors in Diesel Generator Trip Circuits). These spurious trips create confusion and delays in restoring power to the nuclear safety
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GANE - May 25, 1991 - Page 4 Low lube oil pressure trip is still used on emergency starts. NRC Information Notice No. 91-06, p.
2 notes that " Successful mitigation of the effects of accidents or transients and maintenance of the overall reliability of EDGs depends upon operations personnel having (1) sufficient knowledge of the associated instrumentation and controls and (2) the ability to recognize and reset a lock-up condition." Desides the danger posed by losing the autor..atic safety high jacket wat er temperature t rip, experience has shown that the low lube oil pressure trip may activate spuriously. This harardous situation will f.e prevented by reworking the system to overcome the danger of f oreign cont (Mnation t o the pneumatic logic. This is another reason we want to fix the g6ncrator.
CCNCLUSION For these reasons, GANE concludes that the discussion of what to do about the need to prevent the emergency diesel generator from overheating must be enlarged from the narrow debate of switch or operator to an earnest search [
f or a solution to the switch's f ailure.
We offer two suggestions to facilitate the process. An electronic logic to replace the current pneumatic logic may be the solution Georgia Power needs to restore reliability to the diesel g anerators. Another suggestion to enhance safety assurance would be to install a dedicated line to Plant Vogtle from nearby Plant Wilson as a back-up in case all else fails.
In the interest of the public as well as Georgia Power Company, we ask the Commission to review this matter, and assist in assuring the repair of r
this vital component of safety at Nuclear Plant Vogtle. If the regulations l
are not an adequate tool for solving this problem, we encourage you to exercise the fullest power of your position to fulfill your mandate to make j
nuclear power safe and specifically to remedy this unsafe condition.
We have initiated contact w th Georgia Power officials in an effort to explore with its decision makt a the risks posed by current diesel generator practices at Nuclear Plant Vogtle and the possibility of taking mutually 1
agreed upon actions to address those risks. Company representatives have appeared somewhat open to discussing the matter with us but the idea to meet has not yet come to fruition.
GANE - May 25, 1991 - Page 5 We hope that you givr-safety concerns precedence over GANE's procedural unsophistication. And wo hepe that luck remains on out side so that Nuclear Plant Vogtle does not suffor a loss of sta'. ion power involving the currently unreliablo emorgency diesel generators.
Respectfully submitted, 7
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'y Caenn Carroll ltepresentative for GANE j
Iigned and dated in Decatur, Georgia May 25, 1991
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' S ri Service List:
pj*,3 Commissioner Kenneth Carr Chairman U.S. Nuclear Regulatory Commission
.r-o washington, DC 20555 Commissioner James R. Curtiss U.S. Nuclear Regulatory Commission Washington, DC 20555 Conmissioner Thomas Roberts U.S. Nuclear Regulatory Commission Washington, DC 20555 Commissioner Kenneth Rogers U.S',
Nuclear Regulatory Commission Washington, DC 20555 Administrative Judge Charles Dochhoofer Chai rman Atomic Safety and Licensing Board U.S. Nuclear Regulatory Commission Washington, DC.20555 Administrative Judge Emmeth.A. Luebke 5500 Friendship Doulevard Apartment 1923N Chevy Chase, MD 20015 Administrative Judge James H. Carpenter Atomic Safety and Licensing Board U.S. Nuclear Regulatory Commission Washington, DC 20555 Secretary of the Commission U.S. Nuclea r Regulatory Commission Washington, DC 20555 c/o: Emile Julian Docketing and Services Branch Charles A.
Darth, Esquire office of the General Counsel U.S. Nuclear Regulatory Commission Washington, DC 20555 Arthur H. Domby, daquire Troutman, Sanders, Lockerman & Ashmore Candler Du11 ding, Suite 1400 127 Peachtree Street NE Atlanta, GA 30303
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Ernest L.
- Blake, Jr.,
P.C.
i Shaw, Pittman, Potts and Trowbridge l
2300 11 Street tiW Washington, DC 20037 i
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