ML20049H706
| ML20049H706 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 02/25/1982 |
| From: | Garrity J Maine Yankee |
| To: | Clark R Office of Nuclear Reactor Regulation |
| References | |
| JHG-82-42, JHG-82-43, MN-82-34, NUDOCS 8203030470 | |
| Download: ML20049H706 (4) | |
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EDISON De'lVE
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AUGUSTA, MAINE 04336 I
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February 25, 1982 IN-82-34 JHG-82-43 v>
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United States Nuclear Regulatory Commission F
T Washington, D. C.
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Attention: Mr. Robert A. Clark, Chief g
Office of Nuclear Reactor Regulation g
Operating Reactors Branch 3 9,
g~6 Division of Licensing
Reference:
(a)
L', cense No. DPR-36 (Docket No. 50-309)
(b) MYAPCo letter to USNRC dated September 2, 1982 (FMY-81-133)
Subject:
Environmental Qualification of Safety-Related Electrical Equipment
Dear Sir:
On February 12, 1982, our Mr. D. Hansen met with Messrs. C. Nelson and R.
Clark of the United States Nuclear Regulatory Commission and provided information which amplifies our submittal, Reference (b) relative to equipment qualification.
The discussion centered on those items identified in Attachment E of Reference (b) by Resolution Notes 3, 4, and 7 with respect to the safety of continued operation until final resolution is accomplished. The details of the discussion are summarized in the Attachment to this letter.
Based on the details provided in the Attachment, we conclude that continued operation is justified in the interim until final resolution of these items is accomplished.
We trust this information is satisfactory, however, if you should have any questions, please contact us.
Sincerely yours, MAINE YANKEE ATOMIC POWER COMPANY John H. Garrity, Sen[or Director Nuclear Engineering and Licensing JHG/bjp Attachments 0
sq 8203030470 820225 PDR ADOCK 05000309 P
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Justification for Continued Operation for Note 3, 4, and 7 Items on SER Resolution List HPSI-8 The pressure switch is located in the cubicle of the associated HSPI g
pump and provides protection during normal operation by tripping the pump on low suction pressure.
It provides no safety function during DBE, but could trip the pump if it failed in the wrong position. The switch function will be bypassed when a safety injection actuation i
signal is present.
e This is the long term resolution and it will be installed during the March 1982 plant outage. However, safe operation can continue because the radiation dose calculated for a year of posc-LOCA operation is less than that which would cause failure of the eletrical components
.n the switch.
LPSI-4 These valves provide isolation for the RHR System and are only used to achieve cold shutdown after a small break LOCA when the RHR System is valved into service.
If the valves cannot be opened due to failure, the plant can be safely shut down by the use of equipment outside containment (i.e., auxiliary feedwater or feed and bleed operations).
r RC-6,9 The Reactor Coolant System RTDs provide temperature indication as post-accident monitors.
In the event the RTDs fail in the i
post-accident environment, there is an in-core thermocouple qualified i
for the post LOCA environment to provide temperature indication. The cable nnd connector is scheduled to undergo seismic qualification tests in March. Although not specifically qualified, in-core thermocouples of the same design are available. Therefore, there is a high degree of confidence in the availability of multiple readouts.
3 RC-1 The SER resolution note for these transmitters should be changed PAM-5 from Note 3 to Note 1.
They have been tested to a steam test FW-1 profile which exceeds the MY LOCA profile. They have also been tested for radiation dose, although not sequentially, and have 3
radiation hardened components. Therefore, it is our engineering
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judgment that tner trsnsmitters will perform their post-accident functions based on previous testing. They are to be replaced.
However, replacement is not based on a lack of qualification to operate in a harsh environment, but is due to the potential problem 1
of maintaining a ready supply of qualified replacement parts for i
maintenance of the transmitters.
PAM-6 The existing sump level transmitter is qualified to 1971 criteria and is the best available until testing is completed on the unit to current requirements. This transmitter only provides sump level indication and has no safety function.
Therefore, failure of this unit will not affect the safe shutdown of the plant because indications required for operation of the recirculation system are available outside containment, such as discharge pressure of the HPSI and spray pumps and HPSI flow.
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s ELEC-7 These terminal blocks are located in the circuits of solenoid operated valves which operate very quickly af ter an accident. These blocks are very similar to blocks which have been environmentally tested, and based on comparison of materials, configuration, and electrical properties, it is our judgment that they will not fail.
Some of the solenoids require continuous energization af ter their short-term function. The valves operated by these solenoids are redundant to valves located outside containment. Once all valves trip on isolation signal, the failure of a circuit within containment will not disrupt containment integrity.
ELEC-8 The SER resolution note should be changed from Note 3 to Note 1 as these cables have already been replaced with qualified cables.
ELEC-13, These limit switches are mounted on isolation valves, both 16,17, inside and outside containment. The valves are redundant and the 19 limit switches do not affect valve operation. The limit switches provide indication of valve actions associated with containment isolation and ESF immediately af ter the isolation function. The limit switch performs its function at the start of the accident scenerio, and as such, would indicate the valve position prior to accumulation of detrimental environmental ef fects.
If the switch should fail and the valve must be operated in the long term, such as hot leg injection, the operator will verify the valve position through utilization of available flow, temperature, or pressure indication.
PAM-1 Maine Yankee is presently making every effort to complete installation of a qualified hydrogen analyzer for operation by April 1, 1982. The existing analyzer is not qualified to present criteria and may be inaccessible in its present location, due to radiation levels f rom the charging pumps during recirculation.
Using the assumptions and conditions stated in SRP 6.2.5, Maine Yankee has determined that initiation of a containment hydrogen purge within seventeen days of the worst case LOCA will prevent the accumulation of flamable concentrations of hydrogen.
In the interim, Maine Yankee will take the appropriate actions to initiate containment hydrogen purge on the seventeeth day following a LOCA if the existing hydrogen analyzer is not accessible to monitor hydrogen generation.
PA ti-2 These radiation monitors are installed and are operating. The monitors are fully qualified except for the cable to the detector inside containment. Replacement cable is being tested and will be installed during the March outage. These monitors provide indication only and are not necessary to place the plant is a safe shutdown condition.
PAM-8 The containment pressure monitors are installed and one is operational.
The other is in the process of being calibrated.
These are located outside containment. Testing is in progress for a more severe environment, and testing so far has been satisfactory.
Therefore, Maine Yankee concludes that the transmitters will operate satisfactory.
4 PAM-9,10 The monitors for pressurizer safety and relief valve position are presently being tested. Although test results are not yet available, operators have been trained and are cognizant of other indications to determine if these valves are open, including containment pressure response, block valve position indication, solenoid valve indicating light, and quench tank parameters.
AFW-5 The SER resolution note for this item should be changed from Note 3 to Note 5 as this S0V is not required for accident mitigation and should be deleted from the Master List.
MS-3 The pressure transmitters are located in the lower level of the valve house, and the harsh environment is due to an auxiliary steam line break in the upper level, approximately 11 to 14 feet above the transmitters.
The valve house roof is vented to limit steam pressurization of the valve house volume.
If the effects of the line break should affect the transmittters, the plant can be safely shut down by the use of instruments which are external to the valve house.
CS-3 These transmitters monitor containment spray pump pressure to assure pump operation.
If these transmitters should fail due to harsh environment, pump operation can be monitored by pump motor ampers, located in a mild environment, and by containment response to spray.
HSPI-9 The valves are located in the Primary Auxiliary Building on the HPSI pump discharge piping and are similar to valves qualified for use in containment. Due to a lack of documentation on the radiation tolerance of the motors, the motors are being replaced. Operation is required for one day, whereas the one-year dose is calculated to be less than one half the dose tolerance of similar motors. Therefore, Maine Yankee concludes that these motors have more than adequate margin to assure operation for one day.
The SER resolution notes for the following items should be changed from Note 3 to Note 1, as these SOVs have been replaced with qualified SOVs.
CVCS-2,3,5,6,7,8 CAAS-1,2 l
FP-1 HPSI-3,4 l
LPSI-3 l
PS-1,2,3,4 l
PV-1,2,3
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AFW-3 l
CLMS-5 I
FW-2 MS-1,2 PCC-1,4 RC-8 MG-1 l
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