ML19351D831
| ML19351D831 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 11/04/1980 |
| From: | Clark R Office of Nuclear Reactor Regulation |
| To: | Goodwin C PORTLAND GENERAL ELECTRIC CO. |
| Shared Package | |
| ML19351D832 | List: |
| References | |
| TAC-11299, TAC-12369, TAC-13152, NUDOCS 8011200091 | |
| Download: ML19351D831 (13) | |
Text
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ff UNITED STATES
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FE WA5mNGTON, D. C. 20555 b
k November 4, 1980
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Docket No. 50-344 q
L Mr. Charles Goodwin, Jr.
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Assistant Vice President i'
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L.j Portland General Electric Conpany i,
u 121 S.W. Salmon Street 0
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Portland, Oregon 97204
Dear Mr. Goodwin:
On July 24, 1980, the NRC Staff filed, with the Licensing Board in the Trojan Control Building proceeding, a motion for clarification directed toward a license condition imposed by the Board with regard to modifications to correct the Control Building design iciencies.
The Staff's concern was that the license condition impose ad not contain reference to a number of PGE documents which contained impt. cant design provisions and descrip-tions, analytical methods, acceptance criteria and licensee comitments with regard to the Control Building modifications and maintenance of the Control-Auxiliary-Fuel Building Complex once modified.
Based on the license condition imposed by the Board and on Technical Specification 5.7.2.1 which referenced that license condition, it was possible that the Board may have intended that the licensee not comply with those design provisions, analytical techniques, acceptance criteria and licensee commitments which e ra contained in the PGE documents but omitted from the license condition in q "_stion.
Thus, in its motion for clarification, the Staff inquired whethcr the Board, in imposing the license condition but omitting from that condit'.cn the supple-mental PGE documents intended:
solely to impose as license conditions the provisions of PGE-1020 through Revision 4 and PGE Exh. 27, leaving all other material as part of the FSAR descriptions of the Control Building modifica-tion details, supporting analytical evaluations, acceptance criteria, Licensee commitments and implementing procedures which may be changed without prior NRC approval pursuant to 10 CFR 50.59 in applicable instances.
In addition the Staff, in its motion, informed the Board that if, in fact, this were the Board's intent, the Staff would have the licensee appropriately amend the FSAR to include the additional material.
The Staff also indicated that if this were the Board's intent, the Staff would modify Technical Speci-fication 5.7.2.1, which defines the manner in which the Complex, once modified, is to be designed and mintained, accordingly.
In an Order issued on August 27, 1980, the Licensing Board clarified its initial Decision pursuant to the Staff' notion, indicating that, indeed, the Board's -intent was as set forth above.
The Board stated:
'M1 12 0 0 09/
k Mr. Charles Goodwin Portland General Electric Conpany [i]n conclusion, the Staff has indicated in its motion that if the Board affirmatively answers the query set forth above (which it does), then the Staff will have the Licensee appro-priately amend the FSAR to include the additional material.
It will also modify Technical Specification 5.7.2.1 accord-i ngly.
The Licensee has stated that it understands that the supplemental documents are to be treated for regulatory pur-poses as the equivalent of the FSAR, and that the Licensee considers itself bound to all the commitments it nas made therehy.
The Licensee has correctly stated in its Response to NRC Staff's Motion for Clarification, its obligations under the license amendment issued pursuant to the In:tial Decision.
Pursuant to our representation to the Board in our motico for clarification and to the Board's August 27, 1980 Order clarifying its initial Decision, we hereby request that you prepare and submit an amendment to the FSAR which describes for the Control-Auxiliary-Fual Building Conplex the design of the modified Complex, the analytical methods, acceptance criteria and licensee comitments contained in the following documents:
Licensee's letters dated February 28, F. arch 28, June 22, June 29, July 5, 6 and 10, August 13, September 5 and 26, November 21, December 17, 21 and 22,1979, and January 28, February 13 and 21, and March 5, 6, 17, 20, 21 and 27, 1980; testimony filed by Licensee on March 17, 1980; Licensee's answers of April 2 and 14,1980, to NRC Staff questions;
" Licensee's Responses to Interrogatories Dated August 27, 1979 From the State of Oregon" dated September 17, 1979, and PGE-1020, as revised through Revision No. 4.
Provisions of these documents which have been superseded in later documents or which relate to the construction process should of course not be included in the amended FSAR.
Af ter your amending of the FSAR, we will issue a revision to Technical Specification 5.7.2.1 to require that the Complex be designed and maintained to the design provisions contained in the amended FSAR section(s).
The amended FSAR should be submitted at least two months before the effective date of Technical Specification 5.7.2 so that we may have the revised Techni-cal Specification (referencing the amended FSAR) in place and effective upon completion of the modification program.
On this basis, then, your amended FSAR should be submitted to us on or before May 25, 1981.
l Mr. Charles Goodwin Portland General Electric Company In the event that an amended FSAR is not submitted to us in time to have a revised Technical Specification referencing it in effect by July 25, 1981, we intend to revise Technical Specification 5.7.2.1 by this date to include references to all the documents cited above.
On another matter, on February 22, 1980, we sent you our Safety Evaluation Report (SER) concerning concrete masonry wall design criteria (the " wall problem") for the Trojan Nuclear Plant.
That SER set forth the basis for the Staff's concurrence that Trojan could resume operation on December 31, 1979, following PGE's filing of LER 79-15 (November 4, 1979) and supplemental material to resolve the " wall problem." Also, attached to that letter was an NRC masonry consultant's report which indicated that certain aspects of the Trojan concrete msonry design criteria addressed in the Staff's SER may not provide for adequate structural integrity of the Trojan walls.
Further investigations by PGE confirmed that certain aspects of the criteria relied upon in the NRC Staff's SER were not adequate.
A revised concrete masonry wall design criteria which remedied the identified deficiencies was agreed upon on June 28, 1980, after intensive deliberations between the NRC Staff and PGE. The enclosed SER supplement addresses this revised criteria, and is the basis for the Staff's agreement issued on July 12, 1980 that Trojan could resume operation.
As discussed in more detail in the enclosed wall problem SER Supplement, the masonry wall criteria provide reasonable assurance that the Trojan Nuclear Plant will withstand the occurrence of an earthquake up to and including the SSE specified for Trojan, with margin.
However, the OBE criteria, which control the design of the walls, are not satisfied.
Therefore, it is our position--which we statec in our original wall problem SER of February 22, 1980 and again here--that the earthq~uake shutdown level should be kept at its current reduced value of 0.08, as specified in license condition 2.C.
9 (10)(b)(ii), until full 0.15g OBE wall qualification has been demonstrated.
As you are aware, this license condition relates to the Control Building design deficiencies, not to the wall problem, and is due to expire on Juiy 25,1981.
Therefore, we need a specific commitment from you that the 0.089 shutdown level will be maintained if the masonry wall full OBE quali-fication is not achieved by the time this license condition expires.
Our letter to you of July 3,1980 requested that you respond to certain items contained in IE Bulletin 80-11 on the subject of masonry wall design and clean l
b Mr. Charles,Goodwin Portland General Electric Corpany up the numerous documents that relate to the design criteria for single and double wythe and composite masonry walls for Trojan so that the design criteria for all masonry walls are contained in one place.
The situation of numerous documents that exist on this subject is similar in many respects to the number and conplexity of documents that exist on the Control Building modification program.
We therefore request that an amendment to the FSAR on masonry wall design criteria be included with the FSAR amendment on the Control Building modification program requested above.
This would permit Technical Specification 5.7.1 to be updated in the same time frame as Tech-nical Specification 5.7.2 and bring all structural matters to a final resolution.
Please respond to each of these items within thirty days of your receipt of this letter.
Sincerely, bU Robert A. Clark, Chief Operating Reactors Branch #3 Division of Licensing
Enclosure:
Concrete fiasonry SER Supplement cc:
w/ enclosure See next page
l l
l Mr. Charles Goodwin, Jr.
Portland General Electric Company cc:
Mr. Ronald W. Johnson, Esquire Mr. John A. Kullberg Corporite Attorney Route One Portland General Electric Company Box 2502 121 S.U. Salmon Street Sauvie Island, Oregon 97231 Portland, Oregon 97204-Maurice Axelrad, Esquire Robert M. Hunt, Chairman Lowenstein, Newman, Reis, Board af County Commissioners Axelrad and Toll Columbia County Suite 1214 St. Helens, Oregon 97051 1025 Connecticut Avenue, N.W.
Washincton, D. C.
20036 Columbia County Courthouse law Library, Circuit Court Room St. Helens, Oregon 97051 Fra nk W. Ust rande r, J r.
Counsel f or Oregon Dept. of Director, Oregon Department ef Energy E nercy Labor and Industries Buildine, Rcom lli 500 Pacific Building Salem, Oregon 97310 520 S.W. Yam 5ill Portland, Oregon 97204 i
Dr. Hugh D. Paxton 1229 41st Street Mr. Davi d B. McCoy Les Alamos, New Mexico 87544 348 Hussey Lane Crants Pass, Oregon 97526 Michael Malmros, Resident Inspecter U. S. fluclear Regulatory Commissicr William Kinsey, Esquire Trojan Nuclear Plant 1002 N.E. Holladay P. O. Box 0 Portland, Oregon 97232 Rainier, Oregon 97043 Ms. f;ina Bell D r. '. e n n e t h A. k'.cC o l l om, Den-72C S.C. 26th Street E-t1on of E ngineering, Sertland, Oreg:n 97214
- :bitecture anc Techncl:1 F cs oli e i
0+ 1 ncm' 3 *.a: e U ni vers i ty
'. Eugene 5
riwa:er, Oklahoma 7a0"a Coali ::r = :- S a's F ower 215 5.E. 5 t Avenue l
f Scrtiand, Oregon 97214 a
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b Mr. Charles Goodwin, Jr.
Portland General Electric Company cc:
Marshall E. Miller, Esquire, Chairman Atomic Safety and Licensing Board U. S. Nuclear Regulatory Comission Washington, D. C.
20555 Atomic Safety and Licensing Board Panel V. S. Nucler Regulatory Comission Washington, D. C.
20555 Docketing and Service Branch (7)
Office of the Secretary U. S. Nuclear Regulatory Comission Washington, D. C.
20555
' Alan S. Rosenthal. Esquire Atomic Safety and Licensing Appeal Board U. S. Nuclear Regulatory Comission Washington, D. C.
20555 Dr. John H. Buck Atomic Safety and Licensing Appeal Board U. S. Nuclear Regulatory Comission Washington, D. C.
20555 Dr. W. Reed Johnson Atomic Safety and Licensing Appeal Board U. S. Nuclear Regulatory Comission Washington, D. C.
20555 Atomic Safety and Licensing Appeal Panel (5)
U. S. Nuclear Regulatory Comission Washington, D. C.
20555
TROJAN NUCLEAR PLANT CONCRETE MASONRY DESIGN CRITERIA SAFETY EVALUATION REPTRT SUPPLEMENT BACKGROUND What has been labeled the " wall problem" originated in October 1979 while PGE was conducting investigations ar.d analyses required by IE Bulletins 79-02 (Concrete Expansion Anchor Bolts) and 79-14 (Seismic Support As-Built Verification).
It was found that the design criteria used for masonry walls at Trojan were deficient in many respects This discovery lead to a detailed plant walk-down and design verification of atI wal B in the plant which were constructed of concrete masonry block.
PGE pursued corrective action in October, November, and December '979.
Absent this problem, the plant would have been in operation.
Following an intensive review by the NRC staff, Trojan resumed operation on December 31, 1979.
The February 22, 1980 letter from Mr. A. Schwencer of the NRC to Mr.
Charles Goodwin of the Portland General Electric Company (PGE) concerning the Trojan Nuclear Plant concrete masonry wall design criteria (the " wall problem") transmitted the staff's Safety Evaluation Report (SER) on this subject.
The SER set forth the basis for the staff's concurrence that Trojan could resume operation on December 31, 1979, following PGE's filing of LER 79-15 (November 4,1979) and supplemental material to resolve the " wall problem." Also, attached to that letter was an NRC masonry consultant's report which indicated that certain aspects of the Trojan concrete masonry design criteria addressed in the staff's SER may not provide for adequate structural integrity of the Trojan walls, in response to this report, PGE sent letters to the NRC dated February 29, 1980, and March 15, 1980, which submitted their comments on the NRC consultant's report and advised the NRC that they were embarking on a short-term in-situ testing program to confirm the shear capacity of the collar joint between the two wythes of the mortared double block masonry walls at Trojan.
On April 15, 1980, the NRC received a copy of PGE's report containing the results of the in-situ testing.
Upon review of this report, the NRC reached agreement with PGE that Trojan would not resume power operation until agreement between the NRC staf f and PGE could be reached on appropriate revised criteria and remedial actions.
This was documented in the April 17, 1980, IE 1mmediate Action letter to PGE.
- 0. April 1, 1980, PGE submitted supplemental information regarding the competency
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. of the bond between the concrete core and masonry block wythes of the composite masonry walls.
Discussions to resolve the wall problem began on April 17, 1980. The staff met with PGE/Bechtel on May 1 and 2, 1980, to further discuss this matter.
On May 10,1980, PGE filed Supplement 3 to LER 79-15 containing its proposed criteria and methodology for reevaluation of the concrete masonry walls. After further discussions between the NRC and PGE/Bechtel, revised proposed criteria were filed by PGE on June 10, 1980. After additional intensive discussions and meetings between the NRC staff and PGE/Bechtel, final criteria were supplied in the PGE letter to the NRC dated June 28, 1980.
On July 12, 1980, PGE informed IE Region V, via letter, that the June 28, 1980 criteria for resumption of Trojan power operation had been satisfied.
Later that day, IE informed PGE that it had no objection to Trojan resuming power operation.
Results of the application of this revised criteria were provided in the July 25, 1980 PGE letter to the NRC.
On August 22, 1980, PGE submitted a Control / Auxiliary / Fuel Building Complex displacement profile based upon a detailed reanalysis of the existing Complex.
This SER Supplement provides the basis for the NRC staff's concurrence on the resumption of power operation of the Trojan Nuclear Plant and on the adequacy of the concrete masonry wall reevaluation criteria.
DISCUSSION As a result of the additional testing and additional review of the Trojan Nuclear Plant concrete masonry wall design criteria after restart of the plant on December 31, 1979, and the issuance of the NRC staff SER on the matter on February 22, 1980, the following areas of concern regarding the criteria w2re identified:
1)
Integrity of the collar joint on both heavy and standard weight concrete masonry mortared double wythe walls 2)
Appropriateness of the methods to determine wall flexibility used to determine the dynamic loads which the walls must resist.
- 3) Appropriateness of the interstory displacement profiles used to determine the loads imparted to the walls due to this phenomena.
4)
Consideration of the effects of wall flexibility and potential nonlinear displacements on the functioning of safety related systems attached to or in near proximity of the concrete masonry walls.
- The short term PGE in-situ test results addressed only the integrity of the collar joint of mortared double wythe masonry walls.
The IE Immediate Action Letter addressed only the immediately identifiable deficiency associated with the heavy weight mortared double wythe masonry walls based upon the expedited fiRC review of the PGE report.
The continuing discussions between the NRC and PGE/Bechtel failed to approprietely resolve the additional areas of concern, delineated above.
Therefore, it was necessary to extend the concrete masonry design criteria reevaluation to include all walls m the plant, i.e., single wythe, mortared double wythe and composite masonry walls.
Final design criteria were agreed upon by the liRC and PGE/Bechtel on June 28,1980 and are documented in the PGE letter to the fiRC of that same date.
This submittal revised and supplemented the material submitted by PGE prior to that date regarding revisions to the Trojan concrete masonry design criteria, as referenced in the background section of this SER.
In summary, the finalization of this criteria led to the develop-ment of:
1.
Ranges of material properties to be used to determine wall flexibility and strength.
2.
Interstory displacement profiles for the structures containing the masonry walls.
3.
Methods of determining the effects of wall flexibility and displacements on the functioning of safety related systems attached to or in the near proximity of the masonry walls.
Only Safe Shutdown Earthquake (SSE) criteria was addressed at d the criteria were applicable only to walls having safety significance.
The resolution of this issue entailed the development of criteria which would provide for "long term" resolution of masonry design criteria for Trojan. Also,
" interim" criteria were developed which would provide an adequate level of safety for the resumption of power operation prior to performing all modifications required to bring all walls having safety significance into compliance with the "long term" criteria. Walls are to be brought into compliance with the long term criteria by October 31, 1980.
The Trojan Nuclear Plant resumed power operation on July 19, 1980.
On July 25,1980, PGE sent a letter to the fiRC describing the results of their evaluations based upon the revised concrete masonry wall design criteria.
This was within ten days of the resumption of power operation, per the PGE committment contained'in their June 28, 1980 letter.
' In summary, the results of the reevaluations for the resumption of power operation were:
1)
For heavy weight double wythe walls 9 walls modified with throughbolts 2 walls modified with structural steel (1 cantilever)
_1_ wall removed from the STARDYNE model with equipment removed 12 heavyweight double wythe walls 2) for standard weight double wythe walls 4 walls modified with structural steel (no cantilevers) 7 walls accepted for interim based on nonlinear displacement criteria or removed from STARDYNE 11 standard weight double wythe walls 3)
For single wythe walls 5 walls modified with structural steel (4 cantilevers) 10 walls accepted for interim based on nonlinear displacement criteria and/or removed from STARDYNE model 15 single wythe walls 4)
Two double wythe masonry walls with structural frequencies less than 20 cps provide support for safety-related equipment as defined in the June 28 letter.
These walls (one normal weight and one heavy weight) Support instrumentation (local indicators, transmitters and switches) which, although they form part of the system pressure boundary, do not have any control functions; thus, there is no adverse impact on the safety-related systems.
Those walls which have not yet been modified will be reevaluated with the interstory displacements from the finite element analysis.
Those which exceed the 10 and 20 psi interwythe shear or bending criteria will be modified by October 31, 1980. Additionally, on August 20, 1980, PGE submitted a revised displacement profile for the Control / Auxiliary /
Fuel Building Complex based upon a detailed reanalysis of the "as-built" structures. This demonstrated that the profile contained in the June 28 submittal was conservative.
, EVALUATI0tl l
The information presented by PGE in LER 79-15, including supplements 1 and 2, and the additional information contained in PGE submittals of December 13, 22, and 31,1979 were previously evaluated in the February 22, 1979 NRC staff SER. We have reviewed the new information presented by PGE in support of the revised concrete masonry wall design criteria as it supplements and revises the previous criteria.
This information is contained in the PGE April 15, 1980 report on in-situ collar joint shear capability testing at Trojan, in LER 79-15 supplements 3 and 4, and in the PGE letters dated February 29, April 1, June 10 and 28, July 25, and August 20, 1980.
Certain aspects of this revised concrete masonry design criteria have also been reviewed by the NRC masonry consultant, Dr. James Colville. His July 1980 report on this subject (Attachment 1 of this SER) discusses his areas of review and his opinions regarding the adequacy of the criteria employed in each of these areas.
The following contains the NRC staff's evaluation of the material presented by PGE, and factors in the opinions of Dr. Colville.
The criteria used to determine thao a wall is safety significant, contained in the June 28, 1980 PGE letter, are appropriate.
Two levels of criteria were developed.
One level to be met prior to the resumption of power operation and a somewhat more conservative level to be met by October 31, 1980.
These criteria are adequate to provide for safe operation of the Trojan plant since: (1) the criteria to be implemented prior to restart dt not represent significant reduction in margin for the overall structure and the individual safety related walls; (2) the criteria provide reasonable assurance that safety related systems attached to or in the proximity of the walls will function; and (3) a short time frame is necessary to implement the final criteria during which there will be somewhat reduced margin in the seismic resistance of the facility.
The material propertiee used to evaluate the stiffness of the walls to derive loads and the capacities for the walls to resist the required loads are acceptabic, Where insufficient data exists to derive single values for modulii of rupture and tensile bond strength for the wall materials, appropriate ranges (upper and lower bound values) of these material properties are being used in the wall reevaluations.
Also, the calculational methodology used to determine the loads and resulting stresses for the walls is appropriate.
The loads and loading combinations used to reevaluate the walls are contained in Section 4 of Attachment I to the June 10, 1980 PGE letter (Supplement 4 to LER 79-15).
These are in accordance with Section 3.8 of the Trojan FSAR, excluding those loading ccmbinations containing the Operating Basis Earthquake (OBE) loads. The final acceptance criteria for these loading combinations are summarized in the June 28, 1980 PGE letter.
I h In the interim period between resumption of power operation and October 31, 1980, walls which do not have appropriate flexural resistance are evaluated using an energy balance technique. With only three exceptions, this criteria is not applicable to shear walls.
For all walls where it was necessary to employ this technique any safety related systems attached to or in proximity of these walls were evaluated to insure that the inelastic wall displacements could be tolerated.
This use of this technique in the interim, as described in detail in the June 28, 1980 PGE letter, is acceptable.
The interstory displacement profiles used in the reevaluation of the walls in all Seismic Category 1 structures, excluding the Control /
Auxiliary / Fuel Building Complex, are based on existing building analyses.
Due to deficiencies in the design of the Complex (described in detail in materials relative to the Control Building design deficiencies:
LER 78-13) and absent the existence of a displacement profile for the as-built Complex it was necessary to develop a displacement profile.
The development of a profile based upon the appropriate detailed analyses could not be accomplished within a suitable time frame.
Therefore, a profile was developed based upon a reasonably conservative simplified analysis.
This is described in the June 28, 1980 PGE submittal.
This profile was to be used until a detailed analysis was completed.
The results of the detailed analysis, considering all approp-iate criteria, was provided in PGE's August 20, 1980 submittal.
This profile supercedes that cantained in the June 28, 1980 PGE letter and is acceptable. This revised profile confirmed that the profile based upon the simplified analysis was conservative.
These profiles consider only the SSE qualification.
Additionally, an appropriate criteria was developed to account for walls which may be significantly more flexible than assumed in the analyset of attached safety related piping, equipment and components.
The details of the criteria are contained in the June 28. 1980 PGE submittal and the results of its application are contained in the July 25, 1980 PGE letter.
These criteria provide reasonable assurance that piping, equipment and components comprising safety related syster' attached to the more flexible walls will function.
For walls which cannot meet the appropriate criteria and must be stiffened and/or strengthened, the June 10, 1080 PGE letter presented four (4) alternative methods of modification.
Based upon review of these alternatives, we concluded that Alternative 1 and 2 are unacceptable and would not provide for adequate stiffness and structural integrity.
Therefore, in the June 28, 1980 PGE lette, they committed to use only Alternative 3 and 4, which are acceptable. An additional alternative method using reinforced concrete members designed in accordance with ACI 318-71, described in the August 20, 1980 PGE submittal, is also acceptable.
Alternative 3, which consists of clamping double wythe walls 1
' together with tensioned bolts, is acceptable without the necessity for inservice inspection of these bolts.
The inservice inspection to be perfomed on the bolting used for the Control Building Modification, in conjunction with the criteria specified in the PGE submittals for the design of these additional bolts in the environments to which they are exposed, should be sufficient to provide for structural integrity of the walls throughout the life of the plant.
The criteria provide for only SSE qualification and provide reasonable assurance that the Trojan Nuclear Plant will withstand the occurrence of an earthquake up to and including the SSE specified for Trojan, with margin.
However, the OBE criteria for Trojan, which control the design of the walls, are not satisfied, Furthermore, the margins in the existing design criteria have not been quantified.
It is estimated that the acceptance criteria have a theoretical factor of safety of approximately 2.
Such factors as the quality of workmanship, the variability of the material properties, the current structural condition of the walls, and inaccuracies in the structural analysis techniques may combine to reduce this factor of safety.
Therefore, a factor of safety on this order is ogn:;.rhtc.
5 ntification of margin and any required testing was addressed in the December 31,19/9 rui ieu.w a.d the February 22, 1980 staff SER.
Further aspects of this were addressed in the July 3, 1980 NRC letter to PGE regarding IE Bulletin 80-11.
Until the required quantifications of margins are perfomed by PGE and accepted by the NRC and the walls are qualified to the 0.15g OBE for Trojan, the OBE should be kept at its current reduced level of 0.08.
9 CONCLUSION The wall reevaluation methodology described by PGE in their submittals as finalized with the June 28, 1980 PGE letter and supplemented in their August 20, 1980 letter, in conjunction with the use of the appropriate material propertias, loads, and loading combinations and corresponding acceptance criteria, provide reasonable assurance that the walls will withstand the appropriate loads.
The evaluations of safety related systems attached to walls considering increased wall flexibility and displacement provide reasonable assurance that these systems will function properly.
Therefore, we conclude that the criteria are adequate to provide for continued safe operation of the Trojan Nuclear Plant.
However, as discussed in the evaluation section of this SER supplement, the OBE at Trojan should remain at the reduced level of 0.08g until all requ'. red actions are completed by PGE and accepted by the NRC staff.
Date :
Attachment:
Colville Report, July 1980 I