ML20044B798
| ML20044B798 | |
| Person / Time | |
|---|---|
| Site: | FitzPatrick  |
| Issue date: | 02/23/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20044B789 | List: |
| References | |
| NUDOCS 9303040293 | |
| Download: ML20044B798 (4) | |
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION q
WASHINGTON. D.C. 20liti6-0001 j
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l SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.187 TO FACILITY OPERATING LICENSE NO. DPR-59 i
POWER AUTHORITY OF THE STATE OF NEW YORK l
JAMES A. FIT 7 PATRICK NUCLEAR POWER PLANT l
DOCKET NO. 50-333 i
1.0 INTRODUCTION
By letter dated August 10, 1992, the Power Authority of the State of New York
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(the licensee) submitted a request for changes to the James A. FitzPatrick Nuclear Power Plant, Technical Specifications (TS). The requested changes j
would increase the offgas system steam dilution flow isolation setpoints. The
-l changes would increase the offgas dilution steam low flow and high flow-isolation setpoints to 6300 pounds per hour and 7900 pounds per hour, respectively. The proposed steam dilution low setpoint.is designed to ensure adequate steam flow through the recombiner during normal plant operation to prevent overheating or ignition of the catalyst.
The proposed steam dilution i
high setpoint is designed to provide recombiner isolation in the event of a break as described in the Final Safety Analysis-Report (FSAR). The associated.
1 Bases will also be revised to describe more accurately the offgas steam dilution function.
i 2.0 EVALUATION Through radiolysis of the reactor coolant, Boiling Water Reactors produce a
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stoichiometric mixture of hydrogen and oxygen in the reactor core.
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. Subsequently, when these gases are stripped from the coolant in the main' condenser and steam jet air ejector system, the concentration of hydrogen is l
increased. When the concentration exceeds about 4% by volume, the mixture l
becomes flammable. Above about 20% hydrogen by volume, the mixture is detonable.
If these flammable or detonable mixtures are exposed to an ignition source, and if proper design precautions have not been followed, ignition of the offgas mixture can potentially result in injury to plant 1
personnel or in loss of power plant availability.
The condenser offgas system consists of a recombiner, a holdup line, high efficiency filters, activated charcoal beds, isolation valves, and the main stack. This system receives offgas (mainly noncondensibles) from the main condenser and recombines the hydrogen and oxygen continuously.to form steam.
Before recombination, the gas mixture is diluted with steam to reduce the hydrogen concentration to less than-4% by volume. This dilution steam will i
ensure that the gas mixture is maintained below the flammable concentration for hydrogen.
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. The primary method to ensure that the hydrogen concentration is within acceptable limits in the recombiner is direct monitoring of this parameter.
If the continuous hydrogen monitor is not available, the current Radiological Effluent Technical Specifications require, in part, that the following instrumentation be operational and capable of providing automatic isolation of the offgas treatment system under the following conditions:
The offgas dilution steam flow instrumentation shall alarm and automatically isolate the offgas recombiner system at low flow less than 6000 pounds per hour or high flow greater than 7200 pounds per hour.
The low flow setpoint is designed to ensure sufficient steam to prevent i
overheating or ignition of the recombiner catalyst. The high flow setpoint is designed to ensure isolation of a postulated pipe break downstream of the recombiner.
During a recent review of setpoint calculations, the licensee identified that operation of the plant within the stated existing setpoints cannot be assured when instrument loop uncertainty is considered. To ensure operation within the technical specification limits while accounting for loop uncertainty, the licensee has proposed a revision to these limits to provide a wider window for operation using the currently installed instrumentation. Specifically, the licensee proposed to change the low flow setpoint from the present 6000 pounds per hour (lbs/hr) to 6300 pounds per hour and change the high flow setpoint from 7200 pounds per hour to 7900 pounds per hour.
The proposed low flow setpoint of 6300 lbs/hr was established in accordance with the guidance provided in General Electric Service Information Letter 150 (GE SIL 150), Revision 2, which recommends that the low flow setpoint be set at a value no lower than 92% of the design steam flow required to keep the gas mixture below the hydrogen flammability limit. The basis for the minimum value of 92% of the design steam flow, as recommended in GE SIL 150, is to prevent overheating or ignition of the catalyst. The current FitzPatrick design steam flow is 6508 lbs/hr. Ninety-two percent of this design steam flow results in a minimum setpoint of 5987 lbs/hr. When the planned reactor power uprate of approximately 4% is accounted for, the design steam flow becomes 6770 lbs/hr. Ninety-two percent of the power uprated design steam flow results in a minimum setpoint of 6228 lbs/hr. Therefore, the licensee's proposed setpoint of 6300 lbs/hr is conservative for both the current licensed power level and for the planned power uprate.
The proposed high flow setpoint of 7900 lbs/hr was established to provide an adequate operational band for normal plant operations considering loop uncertainty while still ensuring isolation of a postulated pipe break downstream of the recombiner. An engineering evaluation was performed by the licensee to verify that the recombiner will continue to isolate automatically within 5 seconds of a pipe break downstream of the recombiner, as described in l
Section 11.4.4.2 of the FSAR. This evaluation concluded that the pipe break s
. detection and isolation function will still be accomplished within 5 seconds and the increase in the amount of steam released in the event that a pipe break occurs with this new higher setpoint will be insignificant.
The NRC staff has concluded that increasing the offgas dilution steam low flow isolation setpoint to 6300 lbs/hr will ensure adequate steam flow through the recombiner during normal plant operation to prevent overheating or ignition of the catalyst.
Furthermore, the NRC staff has concluded that increasing the offgas dilution steam high flow isolation setpoint to 7900 lbs/hr will continue to provide acceptable recombiner isolation of a postulated pipe break downstream of the recombiner. The new setpoints will also ensure that an adequate operational band exists when instrument uncertainty is considered.
Therefore, the staff finds that the stated changes to the FitzPatrick Radiological Effluent Technical Specifications are acceptable.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the New York State official was notified of the proposed issuance of the amendment.
The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (57 FR 42779). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
5.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, j
that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: Brian C. McCabe Date: February 23, 1993 i
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Docket No. 50-333 February 23, 1993 Mr. Ralph E. Beedle Executive Vice President - Nuclear Generation Power Authority of the State of New York 123 Main Street White Plains, New York 10601
Dear Mr. Beedle:
SUBJECT:
ISSUANCE OF AMENDMENT FOR JAMES A. FITZPATRICK NUCLEAR POWER PLANT (TAC NO. M84376)
The Commission has issued the enclosed Amendment No.187 to facility Operating License No. DPR-59 for the James A. FitzPatrick Nuclear Power Plant. The amendment consists of changes to the Technical Specifications in response to your application transmitted by letter dated August 10, 1992.
The amendment to the James A. FitzPatrick Radiological Effluent Technical Specifications changes the offgas system steam dilution flow isolation setpoints. The changes increase the offgas dilution steam low flow and high flow isolation setpoints to 6300 pounds per hour and 7900 pounds per hour, respectively. The steam dilution low setpoint is designed to ensure adequate steam flow through the recombiner during normal plant operation to prevent overheating or ignition of the catalyst. The steam dilution high setpoint is designed to provide recombiner isolation in the event of a break as described in the Final Safety Analysis Report (FSAR). The associated Bases are also revised to describe more accurately the offgas steam dilution function.
A copy of the related Safety Evaluation is enclosed. A Notice of Issuance will be included in the Commission's next regular biweekly Federal Reaister notice.
Sincerely, Original Sig'Cabe, y: Project Manager ned B Brian C. Mc Project Directorate I-l Division of Reactor Projects - I/Il Office of Nuclear Reactor Regulation
Enclosures:
1.
Amendment No.187to DPR-59 2.
Safety Evaluation cc w/ enclosures:
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