ML17037B649

Letter Regarding a Review of the Mark I Containment Program Action Plan and Enclosed NRC Staff Comments on the Mark I Containment PAP and NRC Load Verification Requirements for Mark I Containment Long Term Program

ML17037B649
Person / Time
Site:	Nine Mile Point
Issue date:	12/23/1976
From:	Lear G Office of Nuclear Reactor Regulation
To:	Rhode G Niagara Mohawk Power Corp
References
Download: ML17037B649 (16)

Text

Docket No.60-220 Niagara Hohauk Power Corporation ATTt<: t/r. Gerald K. Rhode Yice President - Engineerinq 300 Erie Boulevard l/est

. Syracuse, New York 13202 Gentlemen:

RE: NINE NILE, POINT NUCLEAR STATION IJl/IT NO. 1

!fe have completed our preliminary revievi of the "Hark I Containment Program Action Plan" which was submitted on behalf of the Hark I Owners Group by the General Electric Company on October 29, 1976, and

~hich you subsequently endorsed in your letter to the HRC dated November 3, 1976. At the present time the Program Action Plan (PAP) serves as our prirlary source of infomatinn regarding the Nark I Contafnmont Long Term Program (LTP). Although the PAP provides infomation relating to the interaction and schedulinq of specific tasks in the LTP, its docwentation of the LTP task objectives and descriptions is too general and lacks sufficient detail to permit a detemination of the adequacy of the specific LTP tasks. As they are no1~ presented, many of the task descriptions only augment the statement of task objectives rather than delineate the methods that will be utilized to acco~plish each objective. Consequently, Me believe that the PAP should be revised to describe, in detail, tlute objectives and associated methods to achieve each LTP task. Additional comments, for use in preparation of a revision to the PAP, are presented in Enclosure l.

)le have also found that the schedules for those tasks relating to "

the definition of stean loads and to th identification of potential load mitigating devices are poorly defined in the PAP. 1fhile we realize that this situation reflects 'the onqoing efforts of the Hark I Owners Group to develop an effective program to acconplish these tasks, we believe that you should make every effort to establish a comibaient to a well-defined program in as timely a manner as is practicable.

Therefore, wo request that you be prepared to discuss the details of these tasks and their schedules for completion at. meetings beb<een the rIiaIkOwners Group and the IIPC staff during the week of Januar 24, Pjg ~(

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NRC FORM 518 (9-1'6) NRCM 0240 4 VS $ . OOVdRNMdNTPRINTINO OPPICda SOTd dda<d4

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.Niagara Hoha>>k Power Corporation - 2-1977. Horeover, we request that, you provide documentation of the details of these programs in a revision to the t'Iark I Containment Program Action Plan to be submitted to the NRC no later than January 31, 1977.

Sincerely, George Lear, Chief Operating Reactors Branch ¹3 Division of Operating Reactors

Enclosures:

1. NRC Staff Comments on Program Action Plan DISTRIBUTION:

2. NRC Load Verification Docket Require<I~ents for the NRC PDR Hark I Containment Local PDR Long Term Program ORB¹3 Rdg

3. Load Ver i fication Require- TJCarter nents Not Adequately GLear Addressed CParrish SNowicki cc: Arvin E. Upton, Esquire JGuibert LeBoeuf, Lamb, Leiby 8 HacRae OELD 1767 N Street, N. W. OI8E (3)

Washington, D. C. 20036 DEisenhut TBAbernathy Anthony Z. Roi snan, Esquir e JRBuchanan Rois@an, t,'essler and Cashdan ABRS (16) 1026 15th Street, W. W. File 5th Floor Vashington, D. C. 20006 fir . Eugene G. Saloga, Applicant, Coordinator Nine file Point Energy Information Center P. 0. Box Sl Lycoming, Ne:r York 13093 OREICEW ORB ORB¹3 ORB¹3 SDRHAMEW JGuib:acr SNowicki G Lear DATE& 12/ g~/76 12/ Z@ 7-6 12/ Z /76.

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ENCLOSURE 1 NRC STAFF COHHENTS ON THE HARK I CONTAINHENT PROGRAH ACTION PLAN PAP

1. The Proqram Action Plan does not contain sufficient information relating to the program for development of the Long Term Program (LTP) structural acceptance criteria. A detailed description of each sub-task in this program and its associated schedule's required.

2. The Program Action Plan does not provide sufficient information on the programs intended to address NRC staff concerns on hydrodynamic/structural interaction resulting from safety-relief valve ahd LOCA loads.

3. The Program Action Plan does not include a program for establishing general guidelines for the Plant Unioue Structural Analysis following the Load Definition Report. As a minimum, guidelines should be provided to cover items such as load combinations, methods of analysis, components tq be addressed, and any plant unique actions (i.e., modifications) should the acceptance criteria not be met.

4. During the course of the Short Term Program (STP), the NRC staff identified specific load verification reauirements to be resolved in the LTP (see attached Enclosure 2); most of these requirements have. previously been identified to the Hark I Owners Group in meetings and in NRC letters of August 11-13, 1976. The PAP task descriptions should contain sufficient detail to provide assurance that each of these requirements will be adequately addressed in the LTP.

5. 'In addition to the general comment of item 4 above, several load verification requirements identified in the attached Enclosure 3 have not been adequately addressed and/or require additional clarification. The PAP should be revised to address these concerns.

6. He require that you commit to utilize the LLL test results, when available, as part of your progr'am to confirm the validitv of the pool swell analytical model described in Task 5.9 of the PAP.

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tg ENCLOSURE 2 NRC LOAD VERIFICATIOW REQUIREMENTS FOR fQRK I CON AI NHEN L N 0 At1 Iten Basis Torus Downward and Upward Loads A. Additional 1/12 20 tests to refine Resolve downward load anomaly observed in torus downward load January 1976 tests e.g., January load

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December load but December load was used in the plant Unique Analysis.

B. Confirm modeling parameters and No previous test data base with various scaling laws with 1/4 scale tests scale tests to confirm model parameters and scaling laws C. Error and uncertainty analysis STP tests did not include a comprehensive required for LTP tests analysis of test errors and uncertainty D. (1) Establish adequate data base The data base is needed to confirm the for plant unique load analytical model approach to the plant determinati on. unique loads.

I (2) Re-examine validity of Insufficient test data base for several individual sensitivity parameters e.g., STP question regarding parameters (if STP sensitivity validity of several sensitivity parameters approach 'is used) not completely resolved.

E. Additional tests with different Test data base to determine relation between water level but same downcomer dynanic pressure load and torus water level submergence. has not been provided.

F. Three Dimensional Testing t

(1) Confirm upward Confirmation of the 20 reduction factor assumed'n STP based on estimated 3D pressure'oads effcts is needed.

(2) Determine plant local STP 2D tests measured average torus downward loads downward loads.

(3) Investigate effect of No STP data base for this effect.

assymetric downcomer clearing and.vent flow in net torus loads

'1 Item Basis G. Future tests should provide a STP did not provide a good simulation of more realistic simulation of these histories. An interpolation technique drywell pressure and enthalpy was necessary adding uncertainty to the flux history result.

K. For future tests the following effects should be considered (I ) Investigate increased transient STP estimate of this effect is to increase mass and energy release for drywell pressurization rate by 20 . This blowdown cal cul ations and effect not considered directly in STP influence of loads loads.

(2) Determine sensitivity of Pl-ant unique variation of this parameter loads to vent system losses may be siqnificant. Plant unique lationn differences were not directly considered in the STP (3) Consider a postulated break in Present analysis covers only recirculation both the steam and recircu- line break, however, recent information line indicates steam line break may be important.

2. Yertical Reaction Loads Additional tests to confirm the pool STP basis is based on PSTF tests considering swell impact and drag loads on a best fit of data for plain cylinders.

ringheader-downcomer assembly Results of future tests should include the actual vent system geometry.

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3. Drag Loads on Submerged Components A. Consider effect of differential This is an unresolved generic concern pressure across structure due to common to teak I, II and III containments.

bubble propagation B. Obtain 3D test data to confirm STP estimate of these parameters based on horizontal and vertical pool 2D tests is not based on an adequate test velocities for submerged data base

'tructure drag loads

Item Basis

4. Steam Loads (Downcomers, Submerged Structures, Confirmation of current test data used in and Torus Boundary) the analysis is needed since the data Additional two-dimensional full is limited and is a reflection of a scale testing containment dgsiqn quite different from Mark I.

5. SRY Loads A. Additional tests (Monticel lo tests) SRV loads not addressed during STP (fatigue required concern). Inadequate data base for SRV loads.

B. Consider sinole active failure Ho current basis for excluding pool loads in the SRV system. due to LOCA + (1) SRV as currently required for Mk II and III designs.

6. Seismic Slosh Loads Perform tests to determine load Definition of this load was deferred to the magnitude. LTP.

7. Secondary Loads (Tests and/or Analyses)

A. Vent System Thrust Confirmation of the STP calculated loads in the header is needed B. Froth and Fallback Effects GE 1/12 tests are not applicable beyond breakthrough point.

C. Post Pool Swell Waves Same as B

V ENCLOSURE 3 NRC LOAD VERIFICATION REQUIREMENTS MHICH ARE NOT ADEQUATELY ADDRESSED Me have compared the NRC staff load verification requirements for the Long Term Program (LTP), as identified during our review of the Short Term Program (STP), with the commitments obtained from the Hark I Owners in the Program Action Plan and in a letter from General Electric to the NRC (L. Sobon to Y. Stello) dated August 25, 1976, both of which have been referenced on the docket by each t3ark I Owner. From this comparison we have identified those requirements for which commitments from the tiark I Owners remain outstanding or need clarification. These requirements, described below, should be addressed in the PAP.

l. Durino the STP we identified a need for additional test .data to confirm the validity of the sensi tivitv parameters used to determine plant unique loads. These additional test data are required to confirm pool swell load variation over the range of plant unique conditions. The tiark I owners indicated in a meeting with the NRC staff on August 19th that the capability exists to obtain the required data by modification of the 1/4 scale 2D test facility tn other geometries and test conditions. However, the )lark I Owners Group has not yet committed to provide a test data base over the range of the sensitivity parameters (i.e., plant conditions) identified in the STP.

An additional concern relates to confirmation of the validity of the selection process for the sensitivity parameters (e.g., vent area to pool area ratio) which were utilized in the STP. The set of sensitivity parameters utilized in the STP were selected on the basis of engineering judgement; however, further consideration indicates that some of the sensitivity parameters may interrelate with the scaling laws. Therefore, the appropriateness of the sensitivity parameters utilized in the STP must be reexamined and justified in the LTP.

Both of the above-mentioned requirements are applicable regardless of whether the plant unique loads in the LTP are determined from sensitivity parameters or from an analytical model, since the analytical code verification will probably be established using sensitivity factors.

(Refer to item 1.0 of enclosure 2)

2. In our August 19th meeting with the Owners Group, we discussed (a) a need for a closer match between the calculated and measured drywell pressuriza-tion and enthalpy flux in the LTP test programs, (b) consideration of the effects of mass and energy inventory, downstream of the flow restrictions, on the calculated blowdown, (c) consideration of the sensitivity of the pool dynamic load to the vent system losses, and (d) the effects of the type of break (i.e., main steam or recirculation) on the pool swell loads.

Based on the material presented by the Hark I Owners Group, it is not

<<3 clear that the interrelationships between these concerns are being considered in the proper sequence. We believe that the Mark I Owners Group should first study the changes in the drywell pressurization and enthalpy flux rates as a function of changes in blowdown, vent system losses, and break type. Secondly, the revised drywell pressurization and enthalpy flux rates resulting from this study should be matched in the 1/4 2D scale and the 1/12 scale 30 test runs which are intended to improve the load data base.

This requirement does not apply to those direct comparison test runs which are intended to verify the scaling relationships.

(Refer to item 1.H of enclosure 2) 3~ On August 19th, the Owners Group agreed to perform a sensitivity study to compare the containment response for ( 1) a main steam line break and (2) a recirculation line break. The Program Action Plan (Task 2.5) includes a commitment to perform a single representative analysis to satisfy this requirement. The proposed use of a single analysis must be justified in the LTP. (Refer to item 1.H.3 of

~ g enclosure 2) 4 On August 19th, the Hark I Owners Group agreed to quantify horizontal and vertical pool velocities for submersed drag loads and also verbally referenced the Mark III pool dynamics evaluation with regard to the differential pressure loads resulting from bubble propagation. The

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Mark I Owners Group should conmit to the adoption of the generic resolution of bubble propagation loads common to all GE designed BWR containments. (Refer to item 3.A of enclosure 2)

A new requirement for the LTP concerns the vent system thrust loads.

In the STP, the vent system thrusts oads were calculated with a "nominal" vent system loss coefficient and a mass flow rate which is conservative with respect to drywell Dressurization. As discussed in item 2 above, the drywell pressurization will be reevaluated as part of the LTP. The Mark I Owners Group should similarly commit to reevaluate the vent system pressurization and thrust loads in the LTP considering the range of vent system losses and mass flow rates that are conservative with respect to the vent system. (Refer to item 7.A of enclosure 2)