ML20127A468

Summary of 771129 Meeting W/Mark I Owners Group & GE in San Franciso,Ca Re Listed Topics,Including Results & Bases for long-term Program Decision Point 3.List of Attendees & Viewgraphs Encl

ML20127A468
Person / Time
Site:	Millstone, Hatch, Monticello, Dresden, Peach Bottom, Browns Ferry, Nine Mile Point, Fermi, Oyster Creek, Hope Creek, Cooper, Pilgrim, Brunswick, Vermont Yankee, Duane Arnold, Quad Cities, FitzPatrick, 05000355
Issue date:	03/01/1978
From:	Charemagne Grimes Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
References
TAC-07934, TAC-7934, NUDOCS 8706100521
Download: ML20127A468 (7)

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• # NUCLE AR REGULATORY COMMisslON f WA$HING TON, D. C. 20666 5

\..... M 01 m 00CKETS NOS.: 50-219, 50-220, Sn-237, 50-245, 50-249, 50-254, 50-259, 50-260, 45233; 5n-265, 50-271, 50-277, 50-278, 50-293, 50-296, 50-298, 50-321, 50-324, 50-325, 50-331, 50-333, 50-341, 50-354, 50-355, and 50-360.

LICENSEES: Boston Edison Company, Carolina Power & Light Company, Commonwealth Edison Cornpany, Detroit Edison Company, Georgia Power Company Iowa Electric Light & Power Com-pany, Jersey Central Power A Light Com3any, Nebraska Public Power District, Niagara flohawk ?ower Corporation, Northeast Nuclear Energy Company, Northern States Power Company, Philadelphia Electric Company, Power Authority of the State of New York, Public Service Electric and Gas, Tennessee Valley Authority, Vennont Yankee Nuclear Power Corporation.

a FACILITIES: Dyster Creek Nuclear Generating Station, Nine lille Point Unit No. 1, Pilgrim Unit No. 1. Dresden Units Nos. 2 ond 3, Millstone Unit No.1, Quad Cities Units.Nos.1 and 2, 11ontice110, Peach Bottom Units Nos. 2 and 3 Browns Ferry Units Nos.1, 2 and 3. Vemont Yankee, Hatch Units Hos.1 and 2. Brunswick Units Nos.1 and 2, Duane A/nold Energy

-Center, Cooper, Fitzpatrick, Enrico Fermi Unit No. 2, and Hope Creek Units Nos. 1 and 2.

SUBJECT:

SUt1!!ARY OF MEETING HELD ON HOVEMBER 29, 1977 WITH REPPESENTATIVES OF THE HARK 1 OWNERS !ROUP On November 29, 1977, a meeting was held in San Francisco, California i with representatives of the Mark I Owners Group and the General Electric

! Company (GE). The purpose of the meeting was to discuss (1) the results and bases for the Long Term Program (LTP) Decision Point No. 3, (2) i recent developments in the 1/4 scale pool swell test procram, (3) the LTP structural acceptance criteria, and (4)..submittals nade by each of l the Mark 1 Owners regarding the effects of nultiple, subsequent safety /

relief. valve (SRV) actuations. Attendees at the meeting are listed in l Enclosure 1. Enclosure 2 consists of the slides presented at the meeting.

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M 0133 SUntARY B. Kohrs, GE, presented the results of Decision Point No. 33 (0P#3).

The purpose of OP#3 was to select the specific load mitigation features that would be used in the development of the LTP Load Definition Report (LOR) which is currently scheduled to be issued in December 1978.

The Owner's Group had previcusly determined (DP#2) that the ontimum program consisted of a combination of load mitigation and structural modifications.

As a result of OP#3, the number of potential load mitigation features under consideration has been reduced to establish specific configurations for each of the testing programs. The SRV mitigation device had previously been selected (T-quencher) and its testing commenced at the tionticello plant approximately one week prior to the meeting. Based on the projected load magnitudes from the-pool swell mitigation screening tests.ithe -

Owner's Group selected differential-pressure control - reduced submergence, and a vent header deflector device as the-pool swell mitigation options to be provided for in_the LOR. The results of the condensation oscillation studies indicate that the mid-range mass flux is a potentially higher load.

However, the critical condensation oscillation loads appear to be much lower than originally expected. -Therefore, _the Owners Group has approved further analytical studies and model tests, but a mitigation device specifically for condensation oscillations will not be pursued.

J. Humphrey, GE, described the planned 1/4 scale LDR testing program.

The program will consist of series of four test runs for each plant specific geometry (two-dimensional). The scale factor for each plant-will be_ dictated by the torus __ diameter of_ the _. test facility. The torus

- diameter in the test facility is. fixed (93 in.). However, all of the-other principal dimensions can be varied. A total of 36 ceneric tests will be performed to determine load sensitivity parameters (e.g., drywell pressurization and submergence) for the reference plant-design, and a total of 68 to 72 plant-unique tests will be perfomed to determine the base case pool swell loads for each plant in the LDR. Each utility will specify for GE the plant specific conditions to-be tested. The pool swell analytical model wi)I now serve as a backup to the 1/4 scale test program _ and will.

define submerged pool velocities for the drag loads.

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W. Cooper, Teledyne, described the changes to be made to the structural

, acceptance criteria (SAC) in response to comments made by the staff during previous meetings. The major changes included a reduction in the number of service level assignments and provisions for plant-unique conditions. Specific changes to the SAC are identified in Enclosure 2.

The SAC have not yet been identified for the Brunswick plant (the only 4 concrete containment); however, it is expected that the criteria will

! be the same es those for the other plants with the exception of the

! torus. Carolina Power & Light and United Engineers & Constructors are J

currently developing the criteria for the Brunswick torus.

A note on the loading table, Figure 1, indicates that no further evalnation will be required if the stress resulting from the pool swc11 InAds is ter4 than 10% of the allowabic for a specific component.

The purposo vf this provision was to avoio reanalyzing the existing loading for ar. insignificant change. The 10% c: .teria was selected as a measure of insignificance, based on judgement. The staff expressed the concern that this criterion is vaquely expressed and, as a result, its application could neglect inadequate base analyses; e.g., design soecifications for attached piping which did not consider torus motion.

We indicated agreenent with the logic behind the 10% criteria, but requested that the criteria be more explicitly stated and its applica-iloa well documented.

The Owners Group indicated that the seismic loading will be that identified in the FSAR for each plant. The staff cautioned that the Systematic Evaluation Program may result in a redefinition of the seismic loads in the near future. Therefore, the Owners shoeld consider the consequences of higher "g" valves when performing

the LTP plant-unique analyses.

The SAC have been modified to include an SRV discharge in conjunction with the design basis accident and the criteria for the "without differential pressure" case. These provisions were included in response to staff positions on SRV load combinations and the use of differential pressure control, respectively.

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A criterion was added (footnote 12 to figure 4 of Enclosure 2) which would provide a definition of a " local" region for the vent system )

analysis. The staff indicated that the proposed criterion was unacceptable and should be changed to define the local region in i terms of diameter. The Owners Group has recently approved a new J task with the Engineering Decision Analysis Company (EDAC). The results  ;

of this task may provide sufficient justification for the prooosed approach, but that determination cannot be made until the work is completed. The EDAC task will be described in Revision 3 to the Program Action Plan, currently scheduled to be completed in February

• 1978. I A similiar criterion was added (footnote 13 to figure 4 of Enclosure 2) which would permit the allowable stress Smc to be replaced by Sy for th: torus shell. This criterion was included based on the anticipated results of the ASME code case N197, which is supported by work per-formed by Constantino. The staff reques,ted additional references on the Constantino work.

The loading combination technique for piping will also be addressed by a code case, since the code does not specifically require direct addition of primary and secondary stresses. The tiark 1 Owners '

indicated that this consideration is currently at the working group level.

The criteria will consider SSE in conjunction with the DBA for essential pipino. The staff requested that terminolooy " essential" and "non-essential" be modified or clarified to avoid confusion. The example cited was SRV piping inside the drywell. The Owners Group has

apparently verbally agreed to address this piping; however, they i have not specifically identified where the criteria will be applied.

_ The staff requested that this discrepancy be resolved.

The Owners Group requested that the staff provide the status of the i i

request for approval of_the use of the SRSS (square root of-the sum 4

of the squares) load combination philosaphy. The staff indicated that a letter response was being prepared. However, there are significant-

, problems related to the review of the tiark-11 SRSS report which is

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1 further complicated by the time necessary to assess a probabilistic basis. l i The staff conjectured that the SRSS philosophy could be found acceptable '

i for application in the Mark I LTP, provided the application is limited to j specific loading combinations supported by rigorous proof. The staff ,

!' recommended that the Mark I Owners Group abandon the probabilistic basis .

l and propose an acceptance criteria based on the statistical combination i of random dynamic loads. The Owners Group requested that our letter be issued as soon as possible because of the time required for them to develop

) an approach. A conference call will be arranged following the issuance

of the letter.

1 1 The staff discussed the preliminary results of its review of submittals made regarding the ef fects of multiple-consecutive SRV actuations and expressed its concern that the assessments made to date do not provide i adequate support to the operating experience. This is. principally the  ;

l result of the judgement required in extrapolating the Monticello test i results, which have a significant. amount of data- scatter. The proposed

] criteria-for a reassessment of multipl,e-consecutive SRV effects were i described. These criteria would permit the number of valves discharging i to be based on a variation in SRV setpoints, provided the setpoint '

, distribution is supported by test data. No other changes to the i system transient analysis should be made.. The proposed criteria

further describes the manner by which extrapolation factors should

j. be derived from structural response data. All of the criteria were

characterized as a "most probable" estimate of the effects of_ the

transient. In response to questions raised by the Owners Group.- the

! staff indicated that plant specific data may be used if the data are

} provided and justified, and that a plant-unique assessment should be i

perforned even if the transient analysis demonstrates that only a -

! single valve subsequently actuates.

i, At the conclusion of the meeting a number of miscellaneous items l were discussed, which included:

j ' (1) The Revision 3 to the Program Action Plan will identify the

testing options for the Full Scale Test Facility, the.1/4 -

! scale pool swell program changes, the phase 2 extension of i .the condensation oscillation evaluation.. and the canceled i mitigation testing tasks.

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W 01 1973 (2) Preliminary results of the reduced submergence assessment indicate a maximum drawdown of 18 inches occurring in approximately three to five minutes, and a maximum seismic slosh trough depth of approximately 10 inches.

(3) Data from a foriegn test program indicate a strong chugging load dependence with the downcomer frequency. The Owners Group indicated that, with a Mark I downcomer frequency of -

S to 8 Hertz, this should not be a concern. We requested that the Owners Group pursue this matter further.

(4) The Owners Group has approved a new task to be performed by '

EUAC. This task is siniliar to the analyi.ical effort being performed by the Lawrence Livermore Laboratory for the staf f (i.e., fluid-structure interaction effects), and will be described in detail in Revision 3 to the Program Action Plan.

(5) GE described the test matrix for the Monticello:"T-quencher" testing program. The proposed matrix contains a number of optional test series to be performed in the event that a predefined data scatter is exceeded. The staff expressed concerns about the potential repeatability of the data, based on a lack of understanding of consecutive valve actuation effects and the data scatter exhibited in the Monticello ranshead tests. GE indicated that the scope of the test matrix is limited by the plant down-time, but the proposed matrix should provide sufficient repeatability. We indicated that the proposed matrix may not provide sufficient data to validate the quencher discharge analytical model, b.1 JMM C._l. Grimes-Plant Systems Branch Division of Operating Reactors

Enclosures:

As-stated cc: See Dage 7 1

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. . NAR 0 1 578 cc: Docket File (1 ea)

NRC PDR (1 ea)

L PDR (1 ea)

ORB-2 Reading File ORB-2 Subject File ORB-3 Reading File ORB-3 Subject File E. G. Case V. Stello K. Goller T. Carter D. Eisenhut G. Lear D. Ziemann L. Shao W. Butler R. Clark J. Hannon V. Rooney R. Bevan D. Verrelli P. O' Conner J. Shea S. Nowicki G. Lainas C. Anderson N. Su OELD(7)

Ol&E(7)

R. Fraley, ACRS (16)

T. Abernathy J. Buchanan Licensees NRC Participants J. Guibert C. Grimes l

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