ML20044F606
| ML20044F606 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 05/18/1993 |
| From: | Opeka J CONNECTICUT YANKEE ATOMIC POWER CO., NORTHEAST UTILITIES |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20044F607 | List: |
| References | |
| B14450, TAC-M83346, NUDOCS 9305280308 | |
| Download: ML20044F606 (4) | |
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'N UTILITIES cenet.i On.ces. seiden street, seriin. connecticut I
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P.O. BOX 270 HARTFORD CONNECTICUT 06141-0270 l
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L-May 18, 1993
.i Docket No. 50-213 B14450 i
Re:
10CFR50.90 U.S. Nuclear Regulatory Cownission Attention: Document Control Desk Washington, DC 20555 Gentlemen:
I Haddam Neck P1 ant' Proposed Revision to Technical Specifications Reactor Coolant System Pressurizer Code Safeties Lift Tolerance Pursuant to 10CFR50.90, Connecticut Yankee Atomic Power Coinpany (CYAPC0) hereby proposes to amend its Operating License, DPR-61, by incorporating the attached proposed changes into the technical specifications of the Haddam Neck Plant.
r Description of the Proposed Chanaes 1
CYAPC0 is proposing to revise the Haddam Neck Plant Technical Specifications to allow a relaxation in the pressurizer safety valve (PSV) setpoint tolerance to 43 percent above the lift setpoint.
The low drift tolerance of -1 percent-below the nominal setpoint will remain the same as the "as-left" setpoint tolerance.
The proposed change will allow the use of the +3 percent, -1 percent tolerar,ce for the "as-found" acceptance criterion for valve testing consistent with 1989 ASME Section XI, Subsection IWV.
However, the change still requires that the safety valve setpoints be restored to within il percent of.their nominal setpoints following testing if the test exceeds the tolerance of 11 percent.
It is noted that in a letter dated May 5,1992,"' Seabrook Station Unit No.1-requested NRC Staff approval for a similar 10 cense amendment to increase the p'
safety valve setpoint tolerance from il percent. to 13 percent for the "as-(1)
T.
C.
Feigenbaum letter.to - the U.S.
Nuclear Regulatory Commission,
" License Amendment Request 91-11:
Code Safety Valve Setpoint Tolerance i
Relaxation," dated May 5,1992.
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U.S. Nuclear Regulatory Commission B14450/Page 2 May 18, 1993 found" acceptance criterion. The license amendment change was approved by the NRC Staff on September 3, 1992.*
Safety Assessment The Haddam Neck Plant's pressurizer design is governed by ASME code Section VIII.
For a vessel with multiple safety valves, the code requires that:
a.
At least one safety valve shall be set to open at design pressure.
Additional relief valves, if any, shall be set to open at no greater than 105 percent of the design pressure (UG-133a);
b.
Total pressure relief capacity shall be sufficient to prevent the system pressure to rise no more than 10 percent above the system design pressure (UG-125c) and Code Case 1271N(1).
The above code requirements stipulate that:
(a) one safety. valve has to be set at the system design pressure of 2485 psig (2500 psia); (b) the highest relief valve set pressure including tolerance cannot exceed 2625 psia (105 percent of design pressure); and (c) that a safety analysis with new setpoint tolerances be performed to show that the reactor coolant system (RCS) pressure remains below 2750 psia (110 percent of design pressure) for the most limiting overpressurization event.
The lowest setpoint for the-Haddam Neck Plant PSVs is 2485 psig (2500 psia).
Therefore, CYAPCO meets the first requirement.
The highest setpoint of 2585 psig (2600 psia) is within the 105 percent of the design pressure code limit.
Thus, the second requirement is also met.
The most limiting overpressurization event is the design basis loss-of-load event which assumes a
+3 percent setpoint drift with 3 oercent accumulation on all three pressurizer safety valves.
The analysis predicted a maximum pressurizer.
pressure of 2690 psia.
This peak pressure, assuming the +3 percent drift, is well within the acceptance criterion which is 110 percant of design basis pressure of 2500 psia or 2750 psia.
Sianificant Hazards Consideration In accordance with 10CFR50.92, CYAPC0 has reviewed the attached proposed changes and has concluded that they do not involve a significant hazards consideration (SHC). The basis for this conclusion is that the three criteria of 10CFR50.92(c) are not compromised.
The proposed changes do not involve an SHC because the changes would not:
(2)
U.S. Nuclear Regulatory Commission letter to T. C. Feigenbaum, " Issuance of Amendment No.15 to Facility Operating License No. NPF Seabrook Station, Unit No. 1 (TAC No. M83346), " dated September 3, 1992.
p U.S. Nuclear Regulatory Commission B14450/Page 3 May 18, 1993 l
1.
Involve a sionificant increase in the Drobability or Consecuences of an accident oreviousiv evaluated.
The proposed change in the PSV tolerance does not affect any initiating event or affect the consequences of the previously evaluated design basis accidents. The new safety valve setpoints are bounded by the assumptions in the safety analysis. Also, the change in the PSV "as-found" tolerance does not affect radiological releases.
Therefore, there is no increase in the probability or consequences of accidents previously analyzed.
r 2.
Create the oossibility of a new or different kind of accident from any t
previously analyzed.
i The proposed change does not increase the possibility of an accident of a
[
different type since it cannot be an initiating event, and it does not 7
modify plant response to accidents to such a degree that it would be i
considered an event not previously analyzed.
This is simply a setpoint tolerance change that reflects the fact that " drift" occurs during the operating cycle.
The setpoint tolerance change is acceptable because it is within the analysis assumptions.
'f 3.
Involve a sianificant reduction in a marain of safety.
The design basis loss-of-load analysis assuming a +3 percent setpoint tolerance resulted in a maximum pressure for the RCS of 2690 psia which i
is below the acceptance criterion of 2750 psia. The proposed change does i
not impact the other physical protective boundaries, nor degrade the performance of any safety system. Therefore, there is no decrease in the.
1 margin of safety because the "as-left" tolerance of il percent is unchanged.
The increase in the "as-found" tolerance to +3 percent simply reflects the fact that the drift of the setpoint by this much over a cycle is acceptable.
Moreover, the Commission has provided guidance concerning the application of the standards in 10CFR50.92 by providing certain examples (March 6,
- 1986, 51FR7751) of amendments that are considered not likely to involve an SHC.
Although the changes proposed herein are not enveloped by a specific example, the proposed changes do not constitute an SHC since we are only relaxing the "as-found" acceptance criterion for valve testing, and the PSV setpoints will be restored to within il percent of their nominal setpoints following testing.
The safety analysis results are acceptable even with the new setpoint tolerance.
Environmental Consideration CYAPC0 has rev.iewed the proposed license amendment against the criteria of 10CFP,51.22 for environmental considerations.
The proposed changes do not increase the types and amounts of effluents that may be released off site, nor significantly increase individual or cumulative occupational radiation t
7 U.S. Nuclear Regulatoly Commission i
B14450/Page 4 May 18, 1993 exposures. Based on the foregoing, CYAPC0 concluded that the proposed changes meet the criteria delineated in 10CFR51.22(c)(9) for a categorical exclusion t
from the requirements for an environmental impact statement.
The Haddam Neck Plant Nuclear Review Board and Plant Operations Review Committee have reviewed and approved the proposed license amendment and have concurred with the above determination. provides a markup of proposed changes, whereas Attachment 2 provides retyped pages of the Haddam Neck Plant Technical Specifications. The retype of the proposed changes to technical specifications in Attachment 2 refiacts the currently issued version of technical specifications.
Technical specification changes previously submitted are not reflected in the enclosed retype.
CYAPC0 hereby requests the NRC Staff to check for continuity with technical specifications prior to issuance.
Regarding our proposed schedule for this amendment, we request issuance at your earliest convenience, with the amendment effective as of the date of issuance, to be implemented within 30 days of issuance.
In accordance with 10CFR50.91(b), we are hereby providing the State of Connecticut with a copy of this proposed amendment.
Should the Staff require any additional information to process this request, CYAPC0 remains available to promptly provide such information.
Very truly yours, CONNECTICUT YANKEE ATOMIC POWER COMPANY I
bh A_
s J. F.(0pe a O
Execut1 ice President cc:
T. T. Martin, Region I Administrator A. B. Wang, NRC Project Manager, Haddam Neck Plant W. J. Raymond, Senior Resident Inspector, Haddam Neck Plant i
Mr. Kevin McCarthy, Director Radiation Control Unit Department of Environmental Protection Hartford, CT 06116 Subscribed and sworn to before me this / f?Y/ day of
/d1y
, 1993-l
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M r.p n Date Commission _ Expires: /8M/!7 7 4