ML17138A763

Forwards Request for Addl Info Re LOCA & Safety Relief Valve Pool Dynamic Loads in Area of Containment Systems

ML17138A763
Person / Time
Site:	Susquehanna
Issue date:	07/04/1979
From:	Parr O Office of Nuclear Reactor Regulation
To:	Curtis N PENNSYLVANIA POWER & LIGHT CO.
References
NUDOCS 7908300457
Download: ML17138A763 (6)

Text

Docket Nos. 50-387 and 50-388 JUL 0g ig79 Distributi w/encl osure:

t f Docket Fil

,RC PDR Local PDR LWR 83 File D. Vassallo F. Williams 0

~ Parr S. Miner (2)

M. Rushbrook (2)

R. Mattson D.

Ross S.

Varga J

~ Knight R. Tedesco R.

DeYoung V. Moore R. Vollmer Mr. Norman W; Curtis.

M. Ernst Vice President - Engineering R. Denise and Construction OELD Pennsylvania Power 8 Light Company IE (3)

BCC:

JBuchanan 2 North Ninth Street TAbernathy Allentown, Pennsylvania 18101 ACRS (16)

SUBJECT:

SUSQUEHANNA STEAM ELECTRIC STATION UNITS NOS.

1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION In our October 2, 1978 and May 15, 1979 letters to you requesting additional information in the area of containment

systems, we indicated the review did not include the information presented in the Design Assessment Report (DAR).

We have now reviewed the portions of Revision 1 to the DAR which provide the information on LOCA and SRV pool dynamic loads and find that we need additional information.

The specific information. required is 18sted in the Enclosure.

Please inform us when this requested additional information will be avail h6le for our review.

Please contqdt us if you desire any discussion or clarification of the

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information requested.

l, Sincerely, ggpnsl signed bT Plan Pdgl'lan D. Parr, Chief

Enclosure:

As stated Light Water Reactors Branch No.

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021.0 Containment S stems Branch 021.69 The LOCA and SRY related pool dynami'c loads that are currently accept-able to us are discussed in NUREG-0487..

Table IV-1 of NUREG-0487 summarizes these Mark II pool dynamic loads, Py letter, dated February 2,

1979, you indicated on Table IV-1 the LOCA related dynamic loads acceptable to the staff that will be adopted for SSES.

Revise the DAR to incorporate this information and provide the same infor-mation for the SRV related pool dynamic loads.

For both the SRV and

LOCA loads indicate the alternative criteria that will be used for each item for which an exemption is proposed and provide references that discuss these alternative criteria.

021.70 'ubsection 4.2.1.1 of the DAR state that the drywell pressure trans-ient used for the pool swell portion of LOCA is based on the methodology described in NEDO-21061.

Subsection III.B.3.a.6 of HUREG-0487 requires that a comparison similar to'those presented in reference 1* be made if the model used is different. from the model described in HEDM-10320.

We require the model prior to completion of review of the pool swell calculations.

• Reference

1) Letter "Responses to NRC Request for Additional Infor-mation (Round 3 guestions),"

to J.

F. Stolz (NRC-DPM) from L. J.

Sobon (GE), dated, June 30, 1978.

021-2 021.71 Subsection 4.2.2.2 of the DAR states that the chugging loads on subm raed structures and imparted on the downcomers will be evaluated later.

Provide 021.72 the present status of.these evaluations and the schedule for,your submission of the completed evaluation.

Statements are made in subsections 4.2.3.2 and 4;2.3.3 of the DAR that plant unique data of the SSES intermediate break accident (IBA) and small break accident (SBA) are estimated from curves for a typical Hark II containment.

Discuss the applicability of these analyses (e.g.,

power level, initial conditions, downcomer configuration, etc) to SSES.

021.73 Provide the information previously requested in 020.44 regarding loads resulting from pool swell waves following the pool swell process or seismic slosh.

Discuss the analytical model and assumptions used to perform these analyses.

021.74 Provide a list and drawing to identify all piping, equipment instrumentation and structures in containment that may be subjected to pool dynamic loads.

In addition, provide drawings to show the location of access galleys in the wetwell, the vent vacuum breaker configuration, wetwell grating, vent bracing configuration, vent configuration in the pedestal region of wetwell and large horizontal =structures in the pool swell zone.

021.75 Discuss the applicability of. the generic supporting

programs, tests and analyses to SSES design (i.e.,

FSI concerns, downcomer stiffners, downcomer d)ameter, etc'f.

021-3 021.76 Provide the time history of plant specific loads and assessment of responses of plant structures, piping, equipment and components to pool dynamic loads.

Identify any significant plant modifications r'esulting from pool dynamic loads considerations.

021.77 Provide figures showing reactor pressure, quencher mass flux and suppression pool temperature versus time for the following events:

(1) a stuck-open SRV during power operation assuming reactor scram at 10 minutes after pool temperature reaches 110'F and all RHR systems

.operable; (2) same as event (1) above except that only one RHR train available; (3) a stuck-open SRV during hot standby condition'ssuming 120'F pool temperature initially and only one RHR train available; (4) the Automatic Depressurization System (ADS) activated following a small line break assuming an initial pool temperature of 120'F and only one RHR train available; and (5) the primary system is isolated and dept essurizing at a rate of 100'F per. hour with an initial pool temperature of 120'F and only one RHR train available.

Provide parameters such as service water temperature, RHR heat exchanger capability, and initial pool mass for the analysis.

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021-4 021.78 1'ith regard to the pool temperature limit, provide the following additional information:

(1) Definition of the "local" and "bulk" pool te,perature and their application to the actual containment and to the scaled test facilities, if any; and r

(2)

The data base that support any assumed difference between the local and the bulk temperatures.

021.79 For the suppression pool temperature monitoring system, provide the P

following additional information:

(1) Type, number and location of temperature instrumentation that will be installed in the pool; and (2) Discussion and justification of the sampling or averaging technique that will be applied to arrive at a definitive pool temperature.