ML20041D503
| ML20041D503 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 02/26/1982 |
| From: | Rich Smith VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| FVY-82-22, IEB-79-01B, IEB-79-1B, NUDOCS 8203050363 | |
| Download: ML20041D503 (5) | |
Text
m VERMONT Y AN KME NUCLEAR L30WER CORPORNPION 2.C.2.1 SEVENTY SEVEN GROVE STREET FVY 82-22 RUTLAND. VERMONT OG*101 ff E PLY TO:
ENGINEERING OFFICE 1671 WORCESTER HOAD FR AMINGH AM, M ASS ACH'JSETTS Cf 701 I f LE PHONE G17 872-8100 Fe b rua ry 26, 1982 asesyso g\\.
g.
/,f4R 04 N A United States Nuclear Regulatory Commission 4
Washington, D. C. 20555
!3 T
r Attention:
Of fice of Nuclear Reactor Regulation Mr. D. G. Eisenhut, Director q
/
Division of Licensing g gg Re f e re nce s :
(a) License No. DPR-28 (Docket No.90-271)
(b) VYNPC Letter to USNRC. dated September 4,1981 (FVY-81-131)
Subject:
Env!ronmental Qualification of Safety-Related Electrical Equipment
Dear Sir:
On February 12, 1982, our Mr. D. Hansen met with Messrs. V. Rooney and j
D. Vassalo of bSNkC and provided information which amplifies our submittal, Reference (b), relative to equipment qualification.
The discussion centered on those items identified in Reference (b) by Resolution Notes 3, 4, and 7 with respect to the safety of continued operation until final resslution is accomplished.
The details of the discussion are summarized in the Attachment to t.his letter.
Based on the details provided in the Attachment, we conclude that continued operation is justified in the interim until final resoluion of these items is accomplished. We t rust this information is satisfactory, however, if you should have any questions, please contact us.
Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION R. L. Smith Licensing Engineer RLS/jgh Oh Attachment i'
i i
GI l
8203050363 820226 PDR ADOCK 05000271 P
\\
i Justification for Continued Operation for Note 3, 4, and 7 Items on SER Resolution List CAD-3, 7 The two tiOVs are located in the Reactor Building and are used for post-LOCA hydrogen control. Over the period of a few months after a LOCA, they are operated periodically.
The only harsh environannt is post-LOCA heat up and radiation.
Similar
!!OVs have been qualified for use in containment.
Due to a lack of radiation qualification, the motors are being replaced.
If the motor should fail within the few months that venting is required, alternate venting can be achieved through qualified butterfly valves in the PCAC System.
CAD-2, 10 These SOVs are operated for post-LOCA hydrogen sampling and are operated intermittently for a period of a few months.
The only harsh environment is post-LOCA heatup and radiation.
The re a re four sampling paths available using these SOVs.
In addition, i
there is an independent sampling path using qualified valves of a d? f ferent manufacturer.
HVAC-1, 2 The RRU ventilation fans are located in a mild environment 5
except for post-LOCA radiation, which could be f rom 10 R to 2 6
x 10 R, which is not excessive for a motor.
It is estimated that the cotors will reach their design radiation dose in approximately 900 hours0.0104 days <br />0.25 hours <br />0.00149 weeks <br />3.4245e-4 months <br />. At that time, in the post-LOCA scenario, only ont RHR motor and one RHR service water motor a re required.
If one of the RRU motors should fail, there is a second RRU located in the same corner room.
Fu rthe rmo re,
should the second RRU in each room fail, only the equipment in one corner room (one RHR motor and one RHR service water motor) is necessary at that time in the post-LOCA scenario.
This means that the required shutdown cooling function could be-provided by alternating operation between the two corner rooms. The equipment in each room could be operated for approximately 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> before switching to the alternate room becomes necessary due to heat buildup.
The rooms where the pumps are located are below grade level and are vented.
MS-3 The MOV is the main steam drain valve, and it receives a close signal on PCIS af ter LOCA.
Howeve r, this valve and its counterpart outside containment are closed during normal operation, as they are only required to be open until operating temperature is achieved. All components of this MOV have been related to qualified MOVs except for the radiation tolerance of the motor.
Since the valve is normally closed, it should not be required to function.
If open, it will close within seconds and radiation tolerance is not a significant factor.
A third valve in this line is also normally closed.
NBVl-5, 6, 7 These components (pressure switches and circuit board) are all located in the Reactor Building and are used for post-LOCA safety relief valve position indication.
They are subject to an environment of post-LOCA heatup and a low post-LOCA !
"r v
5 radiation dose of less than 2 x 10 R.
In the event these components should fail, redundant qualified vessel level and
)
drywell pressure indications are available.
If a safety relief valve should be stuck open, the plant operators are sensitive to the situation, are trained to recognize it, and will take appropriate ac tion.
PAM-2, 3 These components monitor safety valve position and are located in containment.
They are currently being qualified.
If they should fall, redundant qualified vessel level and drywell pressure indications are available, and as noted above, the operators have been trained to handle this situation.
PAM-4 As Identified in our NUREG-0737 responses, these radiation monitors were installed to meet a 1/1/82 requirement with complete acknowledgement that qualification testing was in p rog re s s.
Test data for the monitors has since been received and forwarded to FRC.
The cable used in our installation (Rockbestos), however, is still undergoing testing.
Although there is no causc to believe the cable will not pass the remaining tests, the following justification is provided for continued operation.
These monitors are not required to reach safe shutdown.
In addition, redundant qualified vessel level instrumentation and a newly intalled post-accident sampling panel are available to follow thn course of an accident.
IIPCI-18 There is an alternate qualified monitor for this transmitter (See PAM-9, 16).
l PAM-1, 6, 7, These thercocouples monitor drywell air temperature and 12, 14 torus water and air temperature, and perform no safety function.
The plant can be shut down safely without this
[Elec-3, 30*]
indication by using qualified vessel level and drywell pressure indications. These thermocouples are very similar to the thermocouples which will replace them.
They will perform their indication function before failure will occur due to excessive radiation because their primary function is to indicate temperatures during the intial stages of an accident and is not required af ter conditions have been stabilized.
- The resolution note for Elec-29 should be Note 1, and for Elec-30 it should be Note 3.
PAM-9, 16 These torus water level transmitters have already been replaced with qualified transmitters.
The note for SER resolution should be changed from Note 3 to Note 1.
PAM-11 The PAM-11 in the original submittal has already been replaced with qualified transmitters for monitoring drywell pressure.
The note for SER resolution should be changed from Note 3 to Note 1.
RCIC-1, 2 These MOVs are on the RCIC line; one inside containment and one in the steam tunnel, and operate on a low steam pressure signal for LOCA containment isolation and on break detection signal for RCIC line break isolation.
The MOV components are qualified except for radiation sensitive components.
Since the valves perform their function before there is significant radia t io n, they will complete their safety function before radiation dose can cause failure.
RRS-1 The recirculation discharge and bypass valves are always open when the reactor is operating and close on a LOCA signal.
The MOVs are qualified except for the radiation tolerance of the motor. Since the valves perform their function before there is significant radiation, they will complete their safety function before radiation dose can cause failure.
RWCU-2 These MOVs are on the RWCU line, one inside containment (qualified) and one outside containment (qualified except for radiation dose qualification of the motor).
Both valves operata in a very short time af ter LOCA or RWCU break, so radiation dose is not significant relative to expected motor t o le ra nc e.
In the event of LOCA, the inboard valve is qualified, so single failure of the outboard valve (in a mild environment) is acceptable.
In the event of an RUCU break, the inboard valve is in a mild environment and the outboard valve will not see significant ra d ia t io n.
RHR-1, 6 These MOVs are normally closed containment isolation valves which are opened only to provide a suction path for shutdown cooli ng. Opening of these valves is blocked above 140 psig reactor pre ssure.
Radiation sensitive parts in these operators are being replaced.
If the valves should fail to open, an alternate flow path is available through qualified valves.
RHR-11 These HOVs are backup valves to allow flooding the reactor with river water, and are located in the RHR corner room, a mild environment except for post-LOCA radiation.
The MOVs are qualified except for the motor and other radiation sensitive parts.
If these valves should fail, valves are available in the mild environment of the Turbine Building to accomplish the same function by an alternate flow path which is independent of the valves in the RHR corner room.
The alternate valves are connected to the turbine building service water header, which is separate f rom the RHR service water header, and allow water to be pumped to the reactor via the main condenser.
S BG T-1 One of the two redundant standby gas treatment fans is required to provide negative pressure in the Reactor Building in the post-LOCA period for as long as required by radiological conditions.
The fan will accumulate negligible radiation dose during the first 8 days.
Then the fan is assumed to handle containment hydrogen purge which accumulates a radiation source in the SBGT filter.
This accelerates the dose accumulation on the motor and it is estimated that the motor will reach its design dose af ter 20 days. The alternate motor accumulates radiation dose at approximaely half the rate of the operating motor, due to physical separation, and can be used if the first notor should fail.
Due to the length of time that the motors will perform their function prior to failure, sufficient time is available to perform an angineering evaluation of the radiological conditions and determine if further venting is required, and, if required, to allow the connection of ar.
alternate venting system.
CAD-6 These compressor motors provide instrument air for the CAD System and are located in the Reactor Building.
The only harsh environment during post-LOCA operation is hestup and radiation, and in the few months they are required, the raciation dose is 5
appreximately 10 R.
These conditions are not excessive for the motor and it is our engineering judgement that the motor will complete its function before failure can occur.
aese microswitches provide position indication for several ELEC-25 m
valves in the Reactor Building in the PCAC System. The valves receive an isolation signal immediately af ter an accident.
The re f ore, the position indication switches will perform their function before post-LOCA radiation damage occurs.
The valves may have to be reopened to allow containment purging during recovery operations.
If the switches have failed, valve position can be monitored by the results of the purging ope ra t io n,
i.e.,
drywell pressure or stack radiation monitor'ag.
S BGT-4 These SOVs have been replaced with qualified valves.
The note ADS-1 for SER resolution should be changed f rom Note 3 to Note 1.
MS-1, 2 PCAC-1, 2, 8 RHR-8, 9 These MOVs have been qualified by the vendor, so replacement of the motors will not be re qui red. The note for SER resolution should be changed f rom Note 4 to Note 1.
.