ML20083D541
| ML20083D541 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 12/22/1983 |
| From: | PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | |
| Shared Package | |
| ML20083D537 | List: |
| References | |
| NUDOCS 8312280106 | |
| Download: ML20083D541 (9) | |
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i BEFORE THE UNITED STATES NUCLEAR REGULATORY COMMISSION In the Matter of Docket Nos. 50-277 PHILADELPHIA ELECTRIC COMPANY APPLICATION FOR AMENDMENT OF FACILITY OPERATING LICENSES DPR-44 Edward G. Bauer, Jr.
Eugene J. Bradley 2301 Market Street Philadelphia, Pennsylvania 19101 Attorneys for Philadelphia Electric Company 8312280106 B31222 PDR ADOCK 05000277 P
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BEFORE THE UNITED STATES NUCLEAR REGULATORY COMMISSION In the Matter of Docket Nos. 50-277 PHILADELPHIA ELECTRIC COMPANY APPLICATION FOR AMENDMENT OF FACILITY OPERATING LICENSES DP R-44 Philadelphia Electric Company, Licensee under Facility Operating Licenses DPR-44 for Peach Bottom Atomic Power Station Unit No. 2, hereby requests that the Technical Specifications incorporated in Appendix A of the operating License be temporarily amended as indicated by a vertical bar in the margin of attached page 209.
The requested revision would permit the trip function of the of f-gas recombiner hydrogen analyzers to be temporarily bypassed for up to a hrs. per day so as to 1
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' accommodsto a main csndsnasr leak chsck utilizing halium tracar gas without subjecting the plant to a potential transient.
Increased vacuum leakage on the Unit 2 main condensers was observed upon startup of the plant on December 3,
- 1983, following an extended maintenance outage.
Consequently, the off-gas holdup pipe flow is higher, resulting in a reduced holdup period and higher release rates to the environment.
The application of helium tracer gas and mass spectrometer detection is the most ef f ective means available to identify the sources of vacuum leakage.
Other methods of detection have been unsuccessful in identifying the source of the leakage.
These methods included the use of ultrasonic detectors, smoke injection and visual ins pecti ons.
Progress in the leak detection ef fort is not expected unless the more effective helium tracer gas method is utilized.
Under this method, helium is injected into the area l
of suspected vacuum leaks and the off gas is analyzed for l
evidence of helium using a mass spectrometer.
However, the off-gas hydrogen analyzers will respond to the thermal conductivity of either hydrogen or helium.
Thus, it is expected that, when helium is injected near the leak, a false hydrogen spike will be registered by the hydrogen analyzers, result in a trip of the off gas compressor and in a loss of vacuum transient.
The off-gas recombiner serves to recombine radiolytic hydrogen and oxygen conte.ned in the of f-gas.
The purpose of the recombiner is to reduce the hydrogen concentration of the gas 2
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l substantially below its flammable limit of 4 percent.
Recombination also decreases the volume of off-gas to be handled, thereby reducing the velocity of the gas and increasing the holdup time.
Of f-gas plus dilution steam enters the recombiner at about 400 degrees F and exits as high as 900 degrees F.,
depending on the amount of hydrogen being recombined.
The magni tude of the temperature increased through the recombiner provides information on recombiner performance.
Two hydrogen analyzers and sampling systems are used to measure the hydrogen content at the recombiner condenser outlet (downstream of the recombi ner ).
The analyzers provide both monitoring and trip interlocks for the off-gas mcchanical compressors as their f un c ti on.
liigh hydrogen or helium content downstream of the recombi ner would trip the compressors, and result in a loss of vacuum trancient.
To prevent a mechanical compressor trip and plant transient duri'ng testing with helium for vacuum leaks on the mair condenser and associated vacuum systems, Licensee requests a temporary change in the Technical Specifications that would permit the hydrogen analyzer trip f unction to be bypassed for up to 8 hrs. per day.
The hydrogen indication and the recombiner differential temperature will be continuously monitored during the period of time that the trip function is hypassed.
Operator action will be governed by a procedure approved by the Plant Operation and Review Committee, t
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r The recombiner control panel will be continuously monitored during the time that the hydrogen analyzer trips are bypassed.
During steady state power operation, both hydrogen ef fluent concentration and recombiner dif ferential temperature are stable and reliable parameters.
The concentration of effluent hydrogen does not change unless a loss of preheating occurs or a slug of water is induced into the recombiner system.
Neither of these initiating events are expected during steady state operation, and both events are readily identifiable f rom the control panel.
The individual assigned to continuously monitor the recombiner differential temperature will ensure there is no change in recombiner performance and, therefore, equal protection against hydrogen detonation in the holdup pipe is af forded.
Communication will be set up between the individual monitoring the recombiner operation and the mass spectrometer technician.
Indicated hydrogen increases lasting longer than the short durations expected can be confirmed as helium based on the mass spectrometer reading.
Additionally, a temporary hydrogen analyzer that is not sensitive to helium will be installed locally to monitor the hydrogen content downstream of the recombiner.
This hydrogen analyzer will be continuously monitored during the time that the hydrogen analyzer trips are bypassed.
If either the hydrogen level or differential temperature indicate a failure to recombine hydrogen, the mechanical compressors will be tripped manually.
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The large holdup volume of the off-gas system provides sufficient
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dilution of the relatively small amount of hydrogen entering the holdup pipe in the event of a recombiner failure, such that an immediate decision to trip the compressors is unnecessary, therefore allowing ample time to evaluate all parameters.
Safety Hazards Consideration Determination The Commission has provided guidance concerning the application of standards in 10CFR50.92 for determining whether license amendments involve nignificant hazards consideration by providing certain examples which were published in the Federal Register on April 6, 1983 (48 FR 14870).
One of the examples (vi) of an action involving no significant hazards consideration is a change which may in some way reduce a safety margin, but where the results of the change are clearly within all acceptable criteria.
The requested change fits this example.
Temporarily bypassing the of f-Gas Syste m recombiner compressor high hydrogen trip will allow for detection of main condenser leaks and a reduction in off-gas releases to the environment, without subjecting the plant equipment to the detrimental ef f ects inherent in an additional shutdown and startup transient.
The alternative method of monitoring recombiner performance while the trips are bypassed, as described previously, provides the i"
necessary compensatory measures.
Limiting the bypass period to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> per day will ensure that the hydrogen monitoring system is 5
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i normalized each day, therefore providing additional assurance that the recombiner is functioning properly.
It is requested that this temporary provision in the Technical Specifications remain in ef fect through the 30 days following the initial helium i
leak test.
Consequently, the proposed amendment to the Peach Bottom Operating License does not involve a significant hazards I
consideration, since it would nots (1) involve a significant increase in the probability or consequences of an accident previously evaluated, or (2) create the possibility of a new or different kind of accident from any accident previously eval ua t ed ' or (3) involve a significant reduction in a margin of safety.
The Commission's Regulations, 10CFR50.91(a)(5), permits approval of a license amendment involving no significant hazards t
consideration without prior notice and opportunity for a hearing or for public comment, provided an emergency situation exists, in that failure to act in a timely manner would result in derating or shutdown of the Unit.
Continued operation at the elevated off-gas stack release rates, due to the increased vacuum leakage, is inconsistent with the ALARA con cept.
Additionally, our inability to use the helium tracer gas method, due to Technical Speci fication restraints, increases the possibility of a loss of l
vacuum transient which would result f rom further deterioration in condenser leakage, or compressor f ailure induced by the 6
additional load.
Therefore, the current situation at Peach Bottom Unit 2 satisfies the Commission's definition of an f
emergency situation, as described in paragraph 50.91; consequently, we request that the staff dispense with prior public notice and comment in the processing of this amendment applicati on.
Pursuant to 10 CPR Section 170.22, " Schedule of Fees for Facility License Amendments", Philadelphia Electric proposes that this Application for Amendment be considered a Class III Amendment, since the proposed change involves a single safety issue and is deemed not to involve a significant hazards considerati on,
Plant Operation and Review Committee and the Operation and Safey Review Committee (Nuclear Review Board) have reviewed this proposed change to the Technical Specifications and have concluded that it does not involve an unreviewed cafty question or a significant hazards consideration and will not endanger the health and safety of the public.
Respectfully submitted, PHILADELPHIA ELECTRIC COMPANY
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Vice President 7
e COMMONFEALTH OF PENNSYLVANIA ss.
COUNTY OF PHILADELPHIA S. L. Daltrof f, being first duly sworn, deposes and says:
That he is Vice President of Philadelphia Electric Company, the Applicant herein; that he has read the foregoing Amendment to Application for Amendment of Facility Operating Licenses and knows the contents thereof; and that the statements and matters set forth therein are true and correct to the best of his knowledge, information and belief.
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Subscribed and sworn to before me this Mas day of b3 CC"GG, bb ircq((zb cb1
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{j Notary Public JUDITH Y, FRANKLIN Notary Public, Phi a., Phila. Co.
My Commission Expires July 28,1987
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