ML20078R574
| ML20078R574 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 11/12/1983 |
| From: | Schroeder C COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 7603N, NUDOCS 8311150208 | |
| Download: ML20078R574 (4) | |
Text
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) Commonweetth Edison
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one First N4tional Plata. Chicago, Illinois kC Addr:ss R; ply 12: P:st Offics Box 767
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Chicago, filinois 60690 November 12, 1983 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
LaSalle County Station Units 1 and 2 Differences with Respect to Seismic and Hydrodynamic Effects NRC Docket Nos. 50-373 and 50-374 Reference (a):
C. W.
Schroeder letter to H. R. Denton dated November 8, 1983.
Dear Mr. Denton:
At the request of Dr. A.
Bournia of your staff, we submitted Reference (a) regaraing the differences of Units 1 and 2 with respect to seismic and hydrodynamic effects.
This letter revises Reference (a) by adding a discussion of Unit 2 Safety Related equipment.
To the best of my knowledge and belief the statements contained herein and in the attachment are true and correct.
In some respects these statements are not based on my personal know-ledge but upon information furnished by other Commonwealth Edison l
employees and consultants.
Such information has been reviewed in accordance with Company practice and I believe it to be reliable.
If there are any further questions in this matter, please contact this office.
Very truly yours, 4l'2./g3 C. W. Schroeder Nuclear Licensing Administrator 1m cc:
NRC Resident Inspector - LSCS f0 8311150200 831112 I
l PDR ADDCK 05000373 PDR 7603N P
3 ATTACHMENT The following statements and references are pertinent to the conclusion that differences between LaSalle Units have been
. appropriately acknowledged during design and have been previously documented on the LaSalle docket.
Unit 2 Seismic-Analysis The seismic analysis model of LaSalle County Station (LSCS) includes both Unit 1 and Unit 2 structures as shown in Figure 3.7-9 of LSCS-FSAR.
Joints 1 through 17 in this shear structure model represent the Reactor, Turbine, and Auxiliary Buildings of Unit 1 and Unit 2.
Joints 18 through 59 represent the containment structure,
. reactor pedestal,. sacrificial shield, etc. for both Unit 1 and Unit 2.
The enveloped response of Unit 1 and Unit 2 obtained from a seismic analysis of this model is used in the design of the structures, systems, and equipment of both Unit 1 and Unit 2.
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Unit 2 Pool Dynamic Analysis Figure 5.1-1. of LSCS DAR shows the pool dynamic model.
The analysis details and design assessment of the plant for pool dynamic loads is explained in Section 5 of the DAR.
The model shown in DAR Figure 5.1-1 is the same for both Unit 1 and Unit 2 since:
(a)
The containment and internal structures are identical in both Unit'l and Unit 2.
(b)
Unit 1-and Unit 2 are located symmetrically about the geometric (E-W) centerline of the plant.
(c)
The pool size, quencher locations, downcomer vents, and hence the pool dynamic loads and responses, are the sace for both the Unit 1 and Unit 2.
Unit 2 Reactor Internals Analysis The reactor vessel shroud for Unit 2 differs from that on the Unit 1 RPV.
The vessels were made by different fabricators. The moments and loads on the Unit 2 piping / nozzle interface, therefore, differed slightly from those of Unit 1.
The reactor vessel internal loads also differed slightly because of this difference in vessel shrouds.
- The. design adequacy report for the NSS New Loads, NEDO-30159 (July 1983) was forwarded to NRC by C.W. Schroeder letter to H.R.'Denton dated August 5, 1983.
It provided the Unit'2 reactor vessel evaluation including reactor vessel supports and RPV internals.
It also covered the NSSS piping systems (within primary containment) and concluded that the Unit 2 NSSS safety-related equipment retained positive design margins when subjected to NRC approved com' inations of seismic and hydrodynamic loads from the ut_que reactor building structural responses.
Separately, the_ generic fuel lift report NEDE 21175-3-P was augmented with the Unit 2 specific results as had been done for
-Unit 1.
The_ peak accelerations (1.3 and 4.2g) were less for Unit 2 and well within the evaluation basis accelerations (3.6 and 12.0g).
The maximum calculated fuel assembly gap (0.12 inch) was markedly less than the disengagement gap limit (0.52
-inch) for the fuel assembly.
See C.W.
Schroeder letter to A.
Schwencer dated June 20, 1983.
Piping System Analysis Unit 2 Piping systems within LaSalle Unit 2 were specifically analyzed for configurations which differed significantly from the Unit 1 configuration.
A detailed stress report was issued for those differing systems.
Otherwise, the Unit 1 piping analysis was retitled for Unit 2 becuase the two system configurations were the same and the stress reports are identical.
The C.W. Schroeder letter to H.R. Denton dated September 13, 1983 reported the evaluation to NUREG-0808 Load Definitions and all' piping systems (Unit 1 and Unit 2) and all pipe supports were designed with large margins (3x) for the frequencies under question.
Containment Analysis Unit 2 The containment structural adequacy was reported in the final structural results of the LaSalle SRV test covering Units 1 and 2; it was submitted by C.W.
Schroeder letter to H.
R. Denton dated October 14, 1983.
The results indicated wide margins for suppression pool loads on submerged piping, the suppression pool liner and structures.
No_further actions were deemed necessary on the basis of test verification of suppression pool loads.
The thermal adequacy of the suppression pool had been demon-strated by the inplant SRV test of late 1982, the results of which were documented to NRC via transmittals of March 4,1983 (quick look data), March 30, 1983 (general, first appraisal),
August 16,'1983 (detailed thermal evaluation), and the October 14, 1983 transmittal referenced above.
Containment analyses and conclusions for Unit 1 apply to Unit 2 also because the containments are identical including their internal structures.
E 1
. Safety Related Equipment Unit 2 The LaSalle Seismic / Hydrodynamic Qualification Program for safety-related equipment (SQRT) included equipment for both Unit l'and Unit 2.
The equipment.is almost completely replicated between units.-
The.SQRT Summary Sheets, which were submitted to the Commission, identified both units along with.t?3 equipment tag numbers.
Likewise,'the periodic.SQRT. Program Status Reports (eleven separate submittals) also cited applicability to both LaSalle units on the header.to the tables.
The entries in the
. tables were non-designated tag numbers for simplicity of entry.
'The SQRT qualification binders have been reviewed to assure coverage for Unit _2 and where unique differences exist, an augmented qualification data package was inserted for Unit 2.
Three examples of this type were:
- 1) Unit 1 has Conax electrical / penetrations whereas Unit 2 initially has Amphenol electrical / penetrations until' modified at the first refueling outage with Conax inserts; 2) SRV solenoids on Unit 1 are Model IMF-2 whereas those on-Unit 2 until the first refueling outage are-Model CVG-01; and 3) SRV position indicators on Unit 2 are part of.the Set Point Verfication hardware (although independent of that function), whereas Unit 1 has the Crosby LISA devices which are entirely different.
For these latter items a confirm-atory SRV discharge pipe thermocouple confirms the open-closed indication for the SRV valve.
Safety-related Unit 2 equipment is therefore qualified for seism [c and hydrodynamic loads as documented in the LaSalle SQRT program.
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