ML20199D991
| ML20199D991 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 06/17/1986 |
| From: | Whittier G Maine Yankee |
| To: | Thadani A Office of Nuclear Reactor Regulation |
| References | |
| RTR-REGGD-01.097, RTR-REGGD-1.097 7624L-SDE, GDW-86-146, MN-86-81, NUDOCS 8606230151 | |
| Download: ML20199D991 (6) | |
Text
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MAME HARHEE ATOMIOPOWER00mPARUe avaus,,Yl,',?n"e%s (207) 623-3521 June 17, 1986 O
MN-86-81 GDH-86-146 s
Director of Nuclear Reactor Regulation United States Nuclear Regulatory Commission Washington, D. C.
20555 Attention:
Mr. Ashok C. Thadani, Director PHR Project Directorate #8 Division of Licensing
References:
(a)
License No. DPR-36 (Docket No. 50-309)
(b) MYAPCo Letter to USNRC dated February 28, 1985 (MN-85-43)
Regulatory Guide 1.97 Report (c) USNRC Letter to MYAPC0 dated March 13, 1986 -Technical Evaluation Report of Maine Yankee Conformance to R.G.1.97, Rev. 3.
(d) MYAPCo Letter to USNRC dated December 12, 1985 (MN-85-174)
Subject:
Additional Information on Exceptions to Regulatory Guide 1.97.
Gentlemen:
In Reference (b), we described how the guidelines in Regulatory Guide 1.97 are met or will be met at Maine Yankee.
Your letter, Reference (c), requested additional information on Maine Yankee's justification for exceptions to the Regulatory Guide 1.97 guidance.
Attachment A presents further justification for exceptions to the Regulatory Guide 1.97 for 14 of the 22 items identified in Reference (c).
Additional time will be required to respond to the remaining items.
1.
Maine Yankee plans to provide additional information regarding the remaining Regulatory Guide 1.97 exceptions by August 30, 1986.
He trust this information is satisfactory.
Please contact us if you have any questions.
Very truly yours, 8606230151 860617 MAINE YANKEE ATOMIC POWER COMPANY PDR ADOCK 05000309 P
. D. Whittier, Manager p.Juclear Engineering and Licensing Enclosure O
cc: Dr. Thomas E. Hurley D
Hr. Pat Sears ih Mr. Cornelius F. Holden
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MAINE YANKEE ATOMIC POWER COMPANV ATTACHMENT A TO MN-86-81 ADDITIONAL JUSTIFICATION FOR EXCEPTIONS TO REGULATORY GUIDE 1.97 GUIDANCE 1.
NRC Reauest Containment Pressure - The licensee should either provide instrumentation capable of monitoring subatmospheric containment pressures or provide justification for this deviation.
1.
Maine Yankee Response As described in Reference (b), Maine Yankee has containment pressure instrumentation capable of monitoring subatmospheric conditions. Maine Yankee's range for both containment pressure channels is 0-200 PSIA.
3.
NRC Reauest RHR System Flow - Environmental qualification should be addressed in accordance with 10 CFR 50.49.
3.
Maine Yankee Response The RHR system flow instrument channel was addressed in accordance with 10 CFR 50.49, in that, it was determined that this instrument was not required to function for any of the accidents which are analyzed in Maine Yankee's Final Safety Analysis Report (FSAR). Maine Yankee's long term decay heat removal system for post accident conditions will utilize the LPSI flow instruments as the indication to monitor proper operation of the system (see Reference (b), variable type and number: D8).
4.
NRC Reauest RHR Heat Exchanger Outlet Temperature - Environmental qualification should be addressed in accordance with 10 CFR 50.49.
4.
Maine Yankee Resoonse The RHR heat exchanger outlet temperature channel was addressed in accordance with 10 CFR 50.49, in that, it was determined that this instrument was not required to function for any accidents which are analyzed in Maine Yankee's FSAR.
5.
NRC Reauest Accumulator Level and Pressure - Environmental qualification should be addressed in accordance with 10 CFR 50.49.
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_2-5.
Maine Yankee Response The Accumulator level and pressure instrument channels were addressed in accordance with 10 CFR 50.49, in that, it was determined that these instruments are not required to function for any of the accidents which are analyzed in Maine Yankee's FSAR. These instruments are used to monitor and maintain the readiness of the safety injection tanks pre-accident and thus are not required to function for the DBA.
6.
NRC Recuest Accumulator Isolation Valve Position - Environmental qualification should be addressed in accordance with 10 CFR 50.49.
6.
Maine Yankee Resoonse The Accumulator isolation valve position indications were addressed in accordance with 10 CFR 50.49, in that, it was determined that these indications are not required to function for any of the accidents which are analyzed in Maine Yankee's FSAR. The valves, are electically disabled and verified to be in their correct position during start-up. The disabling device is controlled by Maine Yankee's tagging procedures.
The valve controls on the Main Control Board are key lo k switches providing an additional set of administrative barriers to prevent inadvertent closure. Hith the abundant number of precautions taken already, Maine Yankee does not plan any further modification to this system.
7.
NRC Reauest Boric Acid Charging Flow - Environmental qualification should be addressed in accordance with 10 CFR 50.49.
7.
Maine Yankee Response The boric acid charging flow instrument was addressed in accordance with 10 CFR 50.49, in that, it was determined that this instrument is not required to function for any of the accidents which are analyzed in the Maine Yankee FSAR. The amount of boric acid charged into the RCS is calculated by measuring the time the boric acid transfer pumps ran and multiplying it by the flow rate of the pumps, which is a known value.
This calculation is done routinely during normal operations as Maine Yankee's CVCS system is manually batched rather than operated automatically.
8.
NRC Reauest Low Pressure Injection System Flow - The licensee should verify that the provided range encompasses the recommended range.
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- 8.
Maine Yankee Response Reference (b) incorrectly reported low pressure injection flow instrument range as 0 to 300 gpm; the' instrument's range is actually 0 to 3000 gpm.
The instrumentation meets the guidelines of Regulatory Guide 1.97.
9.
NRC Reauest Pressurizer Level - The licensee should provide justification for the deviation from the recommended range or provide the range recommended by the regulatory guide.
9.
Maine Yankee Response As described in Reference (b), pressurizer level instrumentation measures from the bottom to the top of the pressurizer, as recommended by Regulatory Guide 1.97.
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- 10. NRC Recuest Pressurizer Heater Status - The licensee should provide the recommended '
current instrumentation.
- 10. Maine Yankee Response The basis for recommending electric current, as put forth in Reference (c), is inconsistent with the function or purpose portrayed by the regulatory guide. The reviewer has referred back to NUREG-0737 section i
II.E.3.1 and contends that this instrumentation is to be provided to i
prevent overloading a diesel generator. The regulatory guide's purpose is
(
to determine operating status of the heaters. Maine Yankee's monitoring of breaker position accomplishes the regulatory guide purpose of whether the heaters are "on" or "off".
Maine Yankee's Human Factors Task Analysis has determined that for heater status this is the information required. To satisfy NUREG-0737 section II.E.3.1,i;41ne Yankee utilizes diesel generator Kilowatt meters to indicate possible overloading.
The operators are also trained on what loads can and can not be placed on the diesel generators. The NRC, by letter dated July 19, 1983, considers Maine Yankee's actions for NUREG-0737, Item II.E.3.1 complete.
Based on the above, no modifications are planned.
- 11. NRC Reauest Steam Generator Level - The licensee should provide the recommended instrumentation for this variable.
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- 11. Maine Yankee Resoonse Maine Yankee proposes to upgrade the steam generator wide range level instrumentation, which meets the recommended range in Regulatory Guide 1.97, to meet the requirements for Category 1 instrumentation.
This would be accomplished during the 1988 refueling outage or the refueling outage which is at least 6 months following NRC acceptance of this change, whichever is later.
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- 13. IfRC Reauest Condensate Storage Tank Hater Level - The licensee should provide a second category I channel of instrumentation for this variable.
- 13. Eline Yankee Resoonse The following information was previously provided in Reference (d).
The existing plant design already provides redundant level indications and alarms for the DHST. Two level indicators are provided, one remote at the main control board, and one local at the tank. The remote level indicator and its transmitter are powered from a non-vital ac distribution panel, which is in turn fed from either emergency bus through a manual transfer switch. The local level indication, accessible during accidents, consists of a tank mounted pressure-type gauge which is independent of the remote transmitter.
Two level alarms are provided at the main control board annunciator, one indicating low level, and the other indicating low-low level. The setpoint for the low level alarm is 100,000 gallons which provides a minimum of six hours of emergency feedwater supply. The setpoint for the low-low level alarm is 10,000 gallons.
Each alarm is actuated by an individual level switch.
The annunciator itself is powered from a dc distribution panel which is fed from an emergency dc battery.
During power operation, the DHST is a stable reserve of emergency feedwater which is not used for other operational needs and, therefore, is not subject to frequent or rapid changes in inventory. A minimum of 100,000 gallons is maintained in the tank which provides a minimum of six hours of emergency feedwater supply. Normally approximately 120,000 gallons of water are maintained in the tank.
The multiple instruments and power supplies providing DHST level information make the total loss of level indication highly unlikely.
Furthermore, the parameter being monitored has a very slow rate of change.
The addition of another indicator on the main control board is not justified and could have an overall adverse impact on safety in that unnecessary displays on the main control board are contrary to good human factors practices.
In summary, the design of the existing level indicators and alarms is appropriate.
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MAINE YANKEE ATOMIC POWER COMPANY.
) 15. NRC Reauest
. Containment Atmosphere Temperature - The licensee should provide the recommended instrumentation for this variable.
- 15. Maine _ Yankee _ Response This instrumentation is designed and used only for testing purposes.
To indicate cooling of'the containment atmosphere Maine Yankee's Emergency Operating Procedures (EOPs) call for the use of containment pressure.
Containment isolation and spray systems automatically actuate on containment pressure signals. These systems, used for containment isolation and pressure suppression, are designed to prevent a breach of a barrier-to the release of radioactivity. Containment pressure is the
- variable used post-accident to monitor containment integrity, not the temperature of containment atmosphere.
Based on the above, no modifications are planned.
- 16. NRC Reauest Containment Sump Hater Temperature - The licensee should provide the recommended instrumentation or identify alternate instrumentation that provides the same information and satisfies the regulatory guide.
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- 16. Maine Yankee Response As indicated in Reference (b), Maine Yankee takes exception to the provision for instrumentation to monitor this variable. Containment sump 4
water temperature is not a design requirement of Maine Yankee.-
4 Containment sump water temperature is not a variable required to apprise the operator about the operation of the containment spray system which provides for containment pressure suppression. As stated above, Maine Yankee's E0Ps focus on containment pressure, as one of the primary indicators used to monitor containment integrity.
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- 17. NRC Reauest Makeup Flow-in - Environmental qualification should be addressed in accordance with 10 CFR 50.49.
- 17. Maine Yankee Response Makeup flow-in was addressed in accordance with 10 CFR 50.49, in that, it was determined that this instrument was not required to function for any accidents which are analyzed in Maine Yankee's FSAR. For post accident i
conditions long term cooling can be accomplished by using the throttleable l
HPSI system, where flow measurement is available (see, Reference (b),
l variable type and number D7).
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