ML20070H882
| ML20070H882 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 12/20/1982 |
| From: | Hukill H GENERAL PUBLIC UTILITIES CORP. |
| To: | Stolz J Office of Nuclear Reactor Regulation |
| References | |
| 5211-82-301, NUDOCS 8212270268 | |
| Download: ML20070H882 (5) | |
Text
GPU Nuclear Corporation E O Nuclear m'azees48o s
Middletown, Pennsylvania 17057 717 944-7621 TELEX 84 2386 Writer's Direct Dial Number:
December 20, 1982 5211-82-301 Office of Nuclear Reactor Regulation Attn:
J. F. Stolz, Chief Operating Reactor Branch No. 4 Division of Licensing U. S. Nuclecr Regulatory Commission Washington, D.C.
20555
Dear Sir:
Three Mile Island Nuclear Station, Unit 1 (TMI-1)
Operating License No. DPR-50 Docket No. 50-289 Emergency Feedwater System - Seismic This letter is in response to the Technical Evaluation Raport (TER) for TMI-l Seismic Qualification of Emergency Feedwater System contained in your letter of November 16, 1982. We have enclosed respons,a to the issues addressed in that TER.
As suggested in your letter, we have performed a supplemental walkdown of the portions of the ERJ system you have described as non-seismic. The results are included in the enclosure.
In accordance with Generic Letter 81-14 and our replies, we have not described an alternate decay heat removal system since it is our position that with the minor modification noted in our response;, at restart the existing EW system will be able to perform its safety function after the occurrence of earthquakes up to and including the SSE.
Longer term upgrades that are scheduled for the first refueling after restart vill further simplify the plant response to seismic events and reduce the patential for implant fluid spills. Without regard to the foregoing, we note that as discussed in the December 14, 1981 ASLB Partial Initial Decision HP1 cooling which uses only safety grade equip-ment can serve as an alternate decay heat removal system in the event both EFW and main feedwater systems are lost.
With conpletion of the actions addressed in this letter and our previous letters on this sul.;ect, we have completed our review of the seismic capability of the I 8212210'268 82'1320
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o GPU Nuclear Corporation is a subsidiary of the General Pubhc Ut:hties Corporation p
F" MR. J. F. Stolz 5211-82-301 EW system.' - Nevertheless, should ycu identify further questions or deficiencies regarding the EW system please let us know promptly, since it is our intention to complete all identified long term modifications to the system by completion of the next refueling outage.
- cerely, I d D. Hukill U rector, TMI-1 f
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EFW - TER C0! GENTS TER Item 1 Piping (a) "The portion of the recirculation lines for the emergency feedwater pump between manual isolation valves (EF-V 20 A/B and EF-V 22) and the condensate storage tank (CST) "B" were not seismically designed."
Response
The flow through a failed recirculatica line would not present a loss of safety function.
It would only create an inplant spill.
(See also TER ref. 7 Enclosure 2).
Thus, completion of modifications during cycle 6 refueling.is warranted.
TER Item 2 Pips ag (b) "...Hence the condenser hotwell supply lines will be isolated when the water level of the condensate storage tank reaches the technical specification limit."
Re2ponse j
The existing condensate storage tank level instrun.ontation and alarm are not seismic but will be upgraded to safety grade during the Cycle 6 refueling outage. The level signals for the low level and low low level alarms are from the same transmitter, which w:.1 be rerlaced by a qualified instrument. At restart the operator will isolate the EFW system by closing COV 111 A/B and COV-14 A/B whenever a tank reached the tech spec limit following any EFW actuation; and during the interim period before the long term mods are complete, following any recognizable seismic event.
TER Item 3 Piping (c) " Based on the sketch submitted by the licensee, not all connected branch lines from the AFW System arc seiszic class I beyond the first valve and up to a point of three orthogonal restraints."
Respcqye A wal~rdown of the branch lines has been parformed and the connection with the following valves has been judged to be seismically adequate:
EFV-17 EFV-44 cFV-18 COV-27A/B EFV-23 COV-128A/B EFV-24 COV-129A/B EFV-25 COV-130A/B EFV-26A/B COV-131A/B EFV-27A/B COV-132A/B) Isolated when COV-14A/3 shut by operator EFV-28A/B COV-133A/B ' action (See Response to Itec 2).
EFV-29 COV-134A/B EFV-42A/B EFW Bearing Cooling Lines EFV-43A/B
O TER ltem 4 Piping (d) "The instrument air supply line from valve IA-V27 to the AFW system is act seismically qualified."
Response
Although the instrument air supply line from valve IA-V27 to the EFW system is not seismically qualified check valves qualified for SSE conditions are provided to maintain the integrity of the Seismic Class I two hour air backup supply (bottled) for EFW 30 A/B; EFV 8 A, B, C; MSV 6; and MSV 4 A/B.
In
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accordance with figure 3 of our letter of July 7,1982, the following check valves are provided and qualified for SSE.
IAV 1433 IAV 1451 IAV 1445 1431 1645 1448 1655 1460 1446 1658 1458 1651 1656 1647 1636 1663 1643 1634 1437 1641 1649 1439 1455 1461 1660 1457 1463 1661 1653 1637 1449 1443 1639 1454 1452 1628 A/B TER Item 5 Power Supplies a, b, c, "..- we conclude that the present level of seismic capa-Idlity of power supplies is less than OBE, but it will be equivalent to SSE upon completion of the planned modification."
Response
The failure of the power supplies noted will not prevent the EFW system f rom initially performing its safety function. Adequate time exists for manual action to be taken to preserve minimum CSI inventory.
(see TER ref.
7).
The ccmpletion of long cerm mods during Cycle 6 refueling is warranted.
TER Item 6 l
Initiation / Control Systems " Flow switches and control circuitry of recirculation flow contro; valves EFV 8 A, B, and C."
Response
The recirculation flow control valves fail open on loss of control signal.
This does not result in a loss of safety function (see response to Item 1).
GPUN will upgrade the controls for the emergency feedwater pump recirculation valves EF-V-8 A/B/C to safety grade and modify the recirculation valve circuitry to improve system operation at lcw flow conditions.
i
TER Item 7 Initiation /Centrol Systems
" Cable routing to motor operators for main steam supply isolation valves to the turbine driven pump (MS-V-2 A&B) and for the main steam bypass to the condenser valves (MS-V-8 A&B).
Response
GPUN has evaluated the seismic portion of the electrical system associated with the emergency feedwater turbine driven pump.
In accordance with the analysis provided in the TMI-l Restart Report 8.3.9 and TMI-l FSAR 14.1.2.9, failure of the main steam isolation valves to close would result in a blow-down of both steam generators.
Such a transient can be dustained by the unit as described in the FSAR.
The high energy piping, valves and other mechanical components of the EFW turbine driven pump are required to be seismic to prevent seismically induced damage to the motor driven pumps.
Therefore, specific operation of these valves is not required to miticate the consequences of a seismic event.
TER Item 8 Initiation / Control Systems
" Solenoid valves and limit switch which control the valves (MS-V-13A and B) foi providing the pain steam to turbine."
Response
See Response to Item 7.
TER Item 9 Initiation / Control Systems
" Cable routing of motor cperators for main steam isolation valves MS-V1A, B, C & D."
Response
See Response to Item 7.
TER Item 10 Structures - The Turbire Building is seismic Class II and with some stiffenin; it would withatand OBE.
Response
The Turbine Building is a Class II building according to the building codes not seismic Class II.
Nevertheless, the components associated with EFW system per-formance which are located in the Turbine Building could fail without preventing the completion of the EFW safety function. Therefore, the Turbine Building does not require seismic upgrading.
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