ML19270C237

Board Notification 84-115:forwards Info Re Seismic & Structural Design Departures from Licensing & Design Criteria,Relevant to QA & Technical Issues Before Midland Licensing Board for OM-OL Hearing

ML19270C237
Person / Time
Site:	Midland
Issue date:	06/18/1984
From:	Eisenhut D Office of Nuclear Reactor Regulation
To:	Gilinsky, Palladino, Roberts NRC COMMISSION (OCM)
Shared Package
ML19270C238	List: ML19270C237 ML20091Q444
References
TASK-AS, TASK-BN84-115 BN-84-115, OL, OM, NUDOCS 8406190343
Download: ML19270C237 (5)

Text

i Central Files Only Docket Nos: 50-329 OM, OL and 50-330 OM, OL June 18,1984 MEMORANDUM FOR:

Chairman Palladino Commissioner Gilinsky Commissioner Roberts Commissioner Asselstine Commissioner Bernthal FROM:

Darrell G. Eisenhut, Director Division of Licensing

SUBJECT:

BOARD NOTIFICATION - SEISMIC AND STRUCTURAL DESIGN DEPARTURES FROM LICENSING AND DESIGN CRITERIA -

MIDLAND PLANT (BN 84-115)

In accordance with the NRC procedures for Board Notifications, the following information is being provided directly to the Commission. The information relates only to the Midland Plant and constitutes new information potentially material and relevant to quality assurance and technical issues before the Midland Licensing Board for the OM-OL hearing. The appropriate Boards and parties are being informed by copy of this memorandum.

By letter dated April 20, 1984 (Enclosure 1), Consumers Power Company summarized four Safety Concerns and Reportability Evaluations (SCREs) regarding discre-pancies in original seismic calculations. The four SCREs involve equipment, system and structural modifications which were made for various reasons, but for which the engineering analyses have not been and will not be performed to the original design basis and configuration. The letter notes that completed and ongoing analyses using current design criteria have not identified any actual case where the original structure or components would not perform their intented function as required by the original design criteria.

The letter further states that since all required changes as documented in the SCREs have been incorporated into the latest calculations, the final plant design is assured to meet current design criteria and commitment to safety.

SCRE 9 (Enclosure 2) reports that Category I structures were analyzed with a nominal soil modulus without considering the variation of 50% as required by the FSAR. SCRE 15 (Enclosure 3) states that for the seismic analysis of the diesel generator building, the material stiffness for soil under the building was assumed to be the same as undisturbed till material instead of fill material.

In SCRE 42 (Enclosure 4), the use of Bechtel Computer Program CE-931 over-estimated the composite modal damping, which resulted in an underestimation of the building responses for the reactor and auxiliary buildings. SCRE 19 (Enclosure 5) lists numerous seismic and structural concerns identified as a result of the Company's review of design calculations.

Olo@ O W

. As discussed in Enclosure 6, the NRC staff is concerned with discrepancies between the information provided to the NRC staff for its safety review and the information used for plant design and analyses. These SCREs impact statements within the Midland SER and its supplements, and nearing testimony by the NRC staff and its consultants. The staff has determined that further review regarding the significance of these discrepancies is appropriate and will seek additional information and clarifications from the Company to this end.

Further reporting will be provided if this review reveals the need to modify or supple-ment hearing testimony or the Midland SER.

Original signed by DarrellG. Eisenhut Darrell G. Eisenhut, Director Division of Licensing

Enclosures:

1.

J. Cook Letter dated 4/20/84 2.

SCRE 9 3.

SCRE 15 4.

SCRE 42 5.

SCRE 19 6.

G. Lear memo dated 5/23/84 cc: OPE OGC EDO SECY (2)

Parties to the Proceeding C. Bechhoefer, ASLB F. P. Cowan, ASLB J. Harbour, ASLB C. Kohl, ASLAB J. Buck, ASLAB T. Moore, ASLAB ACRS (10) dh

1. 4 5D,W. DL h(h DL:LB #4 DI L

DHood/hmNd EAdi'nsam

'TNovak RStark 6/p/84 6/JG/84 6//g84 6/

84 6/g84 e

CODSumBTS P0W8f

.,,,,,.,,c,

00mpany v.u ~a- - ~mia s-,

.a e,.,, ~,.

c.

.:one : io4s w.n p.m.n a..a.s.

m. w anoi. ism 7ss o4ss April 20, 1984 84-04 #1 Mr J G Keppler US Nuclear Regulatory Co==ission Region III 799 Roosevelt Road Clen Ellyn,'IL 60137 MIDLAND ENERGY CENTER PROJECT FINAL REPORT ON POTENTIALLY REPORTA3tE CONDITIONS SEISMIC AND STRUCTURAL DESIGN CONCERNS FILE:

0.4.9.91 SERIAL:

28026 Because of discrepancies in the original seismic caleblations, the following Safety Concerns and Reportability Evaluations (SCREs) were issued: SCRE 9

-Category I structures were analyzed with a nominal soil modulus without considering the variation of 250I as required by the FSAR; SCRE 15 - for the seismic analysis of the diesel' generator building, the material stiffness for soil.under the building was assumed to be the same as undisturbed till material instead of fill material; an'd SCRE 42 - Use of Bechtel Computer Program CE-931 which overestimated the composite modal damping, which resulted in an underestimatien of the building responses for the reactor and auxiliary buildings.

In addition, SCRE 19 lists both seismic and structural concerns identified as a result of a CPCo,eview of the civil structural design calculations. The items on SCRE 19 vere discussed with Messrs Landsman and Cardner of NRC Region III Inspection and Evaluation during a March 22, 1984 meeting with Bechtel and Consumers Power Company. provides a more detailed description and the circumstances under which the items were discovered. In each case, the original evaluation was that the discrepancies and concerns, respectively, were not reportable under 10CFR50.55(e), but that further evaluation would be necessary for confirmation.

In actuality, the engineering analysis supporting overall plant design and g

resolution of the SCREs has resulted in two basic categories in terus of I

making a final safety evaluation of the SCRE concerns.

1.

Concerns identified in the SCREs. which in f act, have been analyzed to their original design basis and configuration and have been demonst aced to not be safety. concerns, or 2.

Equipment / system or structural modifications have occurred, (for ggg various reasons) and the engineering analyses have not been performed CF to the original design basis and configuraticin. Thus the project has OCO 84-On414-xpnt

..