ML20090F157
| ML20090F157 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 07/16/1984 |
| From: | Hukill H GENERAL PUBLIC UTILITIES CORP. |
| To: | Stolz J Office of Nuclear Reactor Regulation |
| References | |
| 5211-84-2160, NUDOCS 8407200191 | |
| Download: ML20090F157 (8) | |
Text
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GPU Nuclear Corporation g
gf Post Office Box 480
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Route 441 South Middletown, Pennsylvania 17057-0191 717 944 7621 TE:.EX 84 2386 Writer's Direct Dial Number:
July 16, 1984 5211-84-2160 Office of Nuclear P,eactor Regulation Attn:
J. F. Stolz, Chief Operating Reactors Branch No. 4 Division of Liensing U.S. Nuclear Regulatory Commission Washington, D. C.
20555
Dear Sir:
Three Mile Island Nuclear Generating Station Unit 1 (TMI-1)
Operating License No. DPR-50 Docket No. 50-289 EFW System Seismic Interaction Walkdown In response to your letter of June 25, 1984 and subsequent to our walkdown of the TMI-1 Emergency Feedwater System with you and your staff on May 22, 1984 we conducted an in-depth walkdown to identify potential seismic interactions between the Emergency Feedwater System and other systems, components and structures.
Our walkdown included a comprehensive tabulation and disposition of each potential interaction in the cubicles in which EFW equipment is installed in the Intermediate Building and a review of EFW piping in the Reactor Building. (Item 18 of Attachment I concerning EFW piping attached to a Reactor Building stairway is being reanalyzed to assure SSE qualification).
We found a couple of items requiring minor modifications to preclude seismic interactions (Item 4 and 15 of Attachment 1) which will be completed in August, 1984.
Several questions were raised as a result of our walkdown with you and your staff on May 22, 1984.
In addition, several more items were identified during the subsequent GPUN walkdown.
The attached tabulation (Attachment 1) lists all the items cited as a result of the walkdowns and provides the resolutions for each. As previously reported to you, we have also examined piping located in the Intermediate Building that is identified on our flow diagrams as not being Seismic Category I.
This examination was performed to determine if any piping breaks might occur such that they could affect the function of the EFW system or create a harsh environment that would preclude access to the Ir termediate Building.
The results of our evaluation indicate that none of this piping poses an HELB hazard or porsible loss of EFW system function as a result of a seismic event for the reasons detailed in Attachment 2.
8407200191 840716 PDR ADOCK 05000289 hl F
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I GPU Nu:: lear Corporation is a subsidiary of the General Public Utilities Corporation
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We believe that the walkdown we conducted was comprehensive and that we have identified the possible seismic interactions between the EFW System and other structures, systems and components.
In conclusion, we have reviewed the stresses for all high energy pipe in the Intermediate Building whose failure would produce a harsh environment and have determined by analysis or engineering evaluation that this piping will remain intact during and after an SSE. We have also reviewed the FSAR values for allowable limits on piping in the Intermediate Building and only for the case of the auxiliary steam line are the values exceeded. However, based on our evaluation of this line under SSE, the pressure boundary will not be breached.
Therefore, based on the walkdowns performed, a harsh environment will not be created in the Intermediate Building as a result of an SSE and access will, therefore, be assured.
Sincerely, H.D.NaLill Director, TMI-1 HDH/MRK/mle Attachments cc:
R. Conte J. Van Vliet
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ATTACHMENT NO. 1 l_
QUESTIONS AND RESOLUTIONS FROM
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SEISMIC INTERACTION WALKDOWNS OF TMI-1 EMERGENCY FEEDWATER SYSTEM ITEM QUESTION RESOLUTION
mically supported?
Category I.
2.
Four(4) compressed
-Are these lines Yes, two of these are air lines above EFW seismically Seismic Category I and pump EF-P2B (sizes 1",
supported?
two of these are Seis-2",1-1/2",1-1/2").
mic Category III. They are all supported from L
common support i
structures in the vicinity of EF-P2B, L
which per engineering evaluations will remain intact during and after SSE.
3.
Main Steam Line Is piping Seismic Yes.
" Elbow" and " Tee" Category I?
above pump EF-P2B.
4.
Cubicle containing Is anything related Yes.
Instrument Air to EFW in this EFW Related Items In compressor IA-PIA.
cubicle and, if so, The Area: Control-can it be adversely cable for EF-V30A, i.
l affected by non-Power Cables for EF-P2A l
seismic equipment and EP-P2B and Power &
j-in the area?
Control Cables for EF-V1B and EF-V28.
t Seismic Interaction Precluded, as follows:
i
-Instrument Air Receiver IA-T-1A, also l-in this cubicle is seismically anchored and thus cannot damage r
l EFW items.
-Radiation Monitor RMA-2, also in this f
cubicle, will be anchored to the floor to preclude sliding t
impact with power and control cables for EF-V2B and power cable l
for EF-P28.
l
-No other potential F
l interactions with EFW t
i noted.
I L
1
Page 2 of Attachment 1 5.
Floor drain line Can this drain line No - The drain line is above CST cross-fall during a seismic embedded in concrete at connect piping event and damage the the top and bottom.
between C0-V111A/B.
cross-connect?
Our engineering assessment is that the line will not fall during an SSE.
6.
Floor drain line Can this drain line No - see item 5.
above valves EF-V4&5.
fall during a seismic event and damage EF-V4 and 57 7.
2" lines that tie What are these lines These are the OTSG into Main Steam pipes and are they Seismic shroud drains; they upstream of MS-V2A/B.
Category I?
are Seismic Category I.
8.
Restraint / Shield What is this This is an HELB above valve EF-V1B.
structure for?
restraint / shield to protect the EFW cross-connect suction piping from a line break of the adjacent steam header. See FSAR (Updated Version)
Appendix 14A for details.
9.
Fire Water Piping at Is this piping No; however, there are El. 322' in the seismically no EFW components below Intermediate Building.
supported?
this pipe on El. 322' that can be affected.
- 10. Fire Water Pipe What are the Flooding effects of Break.
consequences?
a line break are How can a break enveloped by a feed-be isolated?
water line break. A fire water line break can be isolated from the Turbine Building.
Flooding can be detected by the Intermediate Building sump alarms.
- 11. Operator access Are these platforms Engineering assess-platforms at seismically ment is that these MS-V4A/B.
supported?
platforms have sufficient seismic resistance.
Page 3 of Attachment 1
- 12. Cable trays 284 &
Are these cable Yes.
667 in vicinity of trays seismically valve MS-V4A.
supported?
- 13. 8" main steam line in Is this pipe Seismic Yes.
Instrument Air Category I?
Compressor IA-PIB Cubicle.
Are there HELB's No. Therefore, there postulated in this is no impact on the cubicle?
EFW suction cross-connect pipe in this cubicle.
- 14. Instrument Air Can the air receiver IA-TIB is seismically Receiver IA-T-1B fall and damage the anchored and will not in the same cubicle EFW cross-connect?
fall during an SSE.
with EFW suction cross-connect piping.
- 15. Ladder mounted on Could the ladder fall Ladder mounting bolts Reactor Bldg. wall and damage EFW conduits will be replaced to in EFW-P2B pump room.
for EFW flow indicators assure SSE and control cable for quai!fication.
Valve EF-V30B7
- 16. 3" Drain Header
- a. Could this line
- a. Our analysis indi-for Main Steam fall during an SSE cates that this line Line Steam Traps and impact power cables will not fall during for MS-V2B and MS-V8B7 an SSE.
- b. Could horizontal
- b. Yes, however motion of this line engineering during an SSE result evaluation indicates in impact of the line that impact will not with adjacent cable damage cables.
trays 284 & 667 (which carry cables for MS-V 2A/B, MS-V8A/B, EFW Turbine Driven Pump cables, and cables for Reactor Bldg.
Emergency Cooling)?
- 17. Stairs leading from Can these stairs fall No.
Even if it did El. 305' to 322' at during an SSE and break fall, a broken EFW northwest corner of EFW recirc pipe?
recirc line is not Intermediate Bldg.
critical.
Flooding is not a problem and water loss poses no CST inventory problem for the reasons cited in our earlier correspondence.
(GPUN Ltr. dated 2/4/83 5211-83-040).
Page 4 of Attachment 1
- 18. EFW pipe supported Will the stairwell Analysis performed in from stairs in inside the Reactor response to IEB's 79-4 containment Bldg. remain intact 02 & 14 show that EFW (and thus the EFW piping remains intact line supported) under during an SSE. Some SSE conditions?
questions have arisen about the stairs which are being pursued.
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ATTACHMENT N0. 2 HIGH ENERGY PIPING STRESS ANALYSIS FOR SECONDARY PIPING IN THE INTERMEDIATE BUILDING 1.
Main Feedwater Piping ("B" loop) Upstream of the Feedwater Check Valve Inside the Intermediate Building - As shown in Ref. 1, all stresses in this line are well below the Giambusso stress level criteria for selecting HELB locations. Also, the design code (B31.1) allowable stress limit for the line at operating conditions is not exceeded when the line is subjected to a coincident Safe Shutdown Earthquake (SSE). Thus, the piping is judged to be equivalent to Seismic Category I.
2.
Main Steam Piping Downstream of MS-V8A/B (steam dump to turbine bypass valves) - These lines were ar.alyzed for HELB as covered in Chapter 14 of the TMI-1 FSAR (See Table 14A-3). The HELB analysis indicates that all stresses in these lines are below the Giambusso stress level for selecting HELB locations. Also, the design code (B31.1) allowable stress limit for the line at operating conditions is not ex::eeded when the line is subjected to a coincident SSE. Thus, the piping is judged to be equivalent to Seismic Category I.
3.
Main Steam Piping Downstream of the Main Steam Isolation Valves (MSIV's)
MS-V1A, B, C, D - These lines were analyzed for HELB as discussed in Chapter 14 of the THI-1 FSAR (see Table 14A-3).
The HELB analysis indicates that all stress levels are well below the Giambusso stress level criteria for selecting HELB locations. Also, the allowable stress limit of the design code (B31.1), with the line at the operating conditions, is not exceeded when the line is subjected to a coincident SSE. Thus, the piping is judged to be equivalent to Seismic Category I.
4.
Auxiliary Steam to EFW Pump Turbine - This line carries 200 psig saturated steam to the EFW pump (EF-P1) turbine driver.
This supply of steam is used for operating the EFW pump when main steam is not available (i.e., during testing or hot standby). This line is pressurized whenever either of the TMI-1 auxiliary boilers are operating. The auxiliary boilers are normally not operated when main steam and extraction steam are available. When the plant is operated at load (above approximately 25% load) and 8th stage extraction steam is available, auxiliary steam requirements are satisfied by that source. The auxiliary boilers would be operated during periods of hot standby and low loads (i.e., less than about 25% load) when turbine extraction steam is not available to feed the auxiliary steam system.
We have inspected the auxiliary steam piping supports in the Intermediate Building.
This piping is supported from the ceiling by threaded rod hangers.
It is our assessment that for horizontal seismic accelerations, these supports will not transfer large forces or motions from the building to the piping.
For vertical seismic accelerations, there is a posibility of some force and motion transfer to the piping, but because the overall system flexibility is high it is judged that these effects will be negligible.
Also, the support anchor bolts have been reviewed for seismic resistance capability. The evaluation indicates that support anchor bolts are capable of withstanding seismic loadings.
.. Thus, the piping trill not experience large seismic stresses that could cause a breach of the systems' pressure boundary.
5.
Pipina Downstream of Valves (C0-V14A/B) - We have previously indicated that the piping downstream of C0-V14A/B from the Intermediate Building to a point inside the trench of the Turbine Building may be considered to have seismic resistance based on an analysis done in response to IEB 79-14.
Reference 2 provides the analysis.
6.
Main Steam Code Safety Relief Valve Vent Stacks - As indicated in our letter No. 5211-82-150 dated.7/7/82, the vent stacks for the main steam safety valves are judged to be adequate for seismic events. This judgement is based on the fact that the vent stack is a single vertical run of pipe that is adequately supported for deadweight and discharge loads; the supporting scheme is judged adequate to withstand an SSE.
7.
Main Steam Line Drains - The main steam line drain piping within the Intermediate Building is Seismic Category I through the last valve before the drain line steam trap. The drain lines from the steam trap through the downstream drain piping are identified as Seismic Category III.-
Although the Seismic Category I boundary is upstream of the steam trap, we judge ~(by inspection) the steam drain station (including the shutoff valve just downstream of the trap) to have seismic resistance. Also, these traps were specified to meet Seismic Category I requirements.
During a seismic event the piping downstream of the drain station might be postulated to break. For steam to flow from the break it would have to pass through the trap and would be terminated since.the trap is designed to pass condensate, and close on steam flow. These traps, which have 3/4" socket weld conections are not expected to pass sufficient flashing condensate to preclude operator acce.ss to the Intermediate Building.
References:
1.
GPUNC Final Safety Analysis Report (FSAR) Updated Version -
Appendix 14A, " Design Review for Consideration of Effects of Piping System Breaks Outside Containment".
2.
"GPUNC Topical Report No. 003, Rev. 1. TMI Unit 1 - Docket No. 50-289 USNRC I.E. Bulletin No. 79-14 Final Report" and attached GPUNC TDR No.194, " Final Report to USNRC for I.E.
Bulletin 79-14 Requirements at TMI Unit 1".
Ir/0298e
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