ML19308E091

Forwards Request for Addl Info, Structural Design Criteria for Evaluating Effects of High Energy Pipe Breaks on Category I Structures Outside Containment & Regulatory Position Statements Re FSAR Sections

ML19308E091
Person / Time
Site:	Crystal River
Issue date:	09/01/1973
From:	Schwencer A US ATOMIC ENERGY COMMISSION (AEC)
To:	Rodgers J FLORIDA POWER CORP.
Shared Package
ML19308E092	List: ML19308E091 ML19308E098 ML19308E103
References
NUDOCS 8003200817
Download: ML19308E091 (8)

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4 UNITED S ATES ATOMIC ENERGY COMMISSION Th* p'*

WASH WGTON. D.C. 20H5 tg SEP 1 1973 4.et tio. 50-302 Florida Power Corporation ATTN: Mr. J. T. Rodgers s

Assistant Vice President and fluclear Project Manager P. O. Box 14042 St. Petersburg, Florida 33733 Gentlemen:

l On the basis of our continuing review of the Final. Safety Analysis Report (FSAR) for Crystal River, Unit 3 Nuclear Generating Plant, we find that we need additional information to complete our evaluation. The specific information is listed in enclosure 1 and relates to FSAR Sections 5.0 Containment System and Other Special Structures, 7.0 Instrumentation and Control and 8.0 Electrical Systems. There are also additional conditions that must be met prior to licensing. The Regulatory position on each of these conditions is described in enclosure 2 and relates to FSAR Sections 7.0 Instrumentation and Control and 8.0 Electrical Systems.

The requests and positions in enclosures 1 and 2 related to FSAR Sections 7.0 and 8.0 were discussed with you in some detail at a meeting held August 23, 1973.

In order to maintain our licensing review schedule, we will need a completely adequate response to enclosures 1 and 2 by October 1,1973.

Please inform us within 7 days after receipt of this letter of your

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confinnation of the schedule date or the date you will be able to meet.

If you cannot meet our specified date or if your reply is not fully responsive to our request, it is highly likely that the overall schedule for completing the licensing review for tne project will have to be "00320 087'?

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ed i e-a entended. Sines reassignment of the staff's efforts will require sempletion of the new assignment prior to returning to this project, the extent of the extension will most likely be greater than the delay in your response. Please sontest us if you have any questions regarding the infioriention requested, gy <m -

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REQUEST FOR ADDITI0t!AL IrlFORMATION FLORIDA POWER CORPORATION CRYSTAL RIVER NO. 3 DOCP.ET fl0. 50-302 5.0 CONTAINMEN JYSTEf4 AND OTHER SPECIAL STRUCTURES 5.39 The structural criteria for evaluating the design of Seismic Category I structures which may be subjected to the effects of high-energy line breaks outside the containment are not adequate.

An acceptable set of criteria is contained in the attached Docu-ment (B). Sufficient information should be provided to establish the extent of compliance with these design criteria. Where incon-sistencies or deviations from these criteria are proposed, justi-fication should be provided to demonstrate that your criteria are equivalent with respect to the applicable s,afety margins.

5.40 Provide a summary of natural frequencies and response loads (e.g., in the form of critical mode shapes and modal responses) determined by the seismic system analysis.

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7.0 INSTRUMENTATION AND CONTROL

'7.1.6 The response to Request 7.1.6 states that passive bistable units will be employed to bypass individual trip functions within a reactor pro-tection channel.

It is further stated that passive bistable units will never be installed in more than one protection channel. However, it is.not apparent from the information submitted on this subject that the design prohibits the concurrent use of passive bistable (s) and channel bypass switches in different redundant channels. Such a design will not conform with Section 4.11 of IEEE 279. Therefore, expand your response to state compliance with IEEE 279 in this regard.

If your design is not in conformance, describe the modifications that will be made to provide an acceptable design.

7.2 The response to Request 7.2 states that the only instrument lines penetrating the reactor bu reactor building pressure.ilding are the lines for sensing (input to both actuation systems). However, your response did not state whether the design of these air lines satisfies Regulatory Guide 1.11.

It appears from the description regarding the testing of rea' tor c

building pressure switches (Page 7-14a, Section 7.1.3.3.4 of the FSAR) that these lines do not satisfy the recomendations of Regulatory Guide 1.11. We require that the design satisfy Regulatory Guide 1.11 or to conform to other criteria that provide protection equivalent to that described in Regulatory Guide 1.11.

Provide adequate design detail to demonstrate protection in accordance with the goide or equivalent.

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8.0 ELECIP.ICAL SYSTEMS 8.8 The preferred (offsite) power system is of concern in the following areas:

a.

Power grid stability b.

Delayed access circuit for offsite power c.

Offsite power supplies loading sequence 8.8.1 Section 8.2.1.3 of the FSAR states that unless automatic load shedding is accomplished, the power grid system will collapse upon the loss of the largest generating plant.

It is also stated that transient stability analyses will be made to provide information necessary to design the automatic load shedding systems to ensure that loss of station will not cause a complete loss of the system.

It is our concern that the higher probability of loss of offsite power as a consequence of grid instability increases the dependence on the onsite (emergency) power sources to a greater level than other licensed plants. Therefore, this more frequent burden on the operation of the onsite power system will require unique considera-tions such as providing an onsite power system of proportionally higher reliability and/or additional capability to compensate for the reduced availability of the offsite power system.

Provide an in depth evaluation of the ac power supply which shows that the combined availability of the offsite and onsite power system:

satisfy the requirements of GDC 17.

8.8.2 The response to Request 7.1.7 did not state that the design of the preferred (offsite) power sy' stem meets GDC 17 with regard to the availability of the delayed access circuit to the transmission net-work.

It was indicated in our request for information that where a conflict exists between the " dight hour" provision of Section 5.2.3(4)

-of IEEE 308-1971 and GDC 17, the applicable provisions of GDC 17 govern. Unless it can be demonstrated that the alternate preferred source (emanating from Unit 1 and 2 startup transformer low voltage windings) can be made available.in sufficient time to assure that specified acceptable lim'its are not exceeded, we require that the design be modified to pr' vide this assurance required by GDC 17.

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'8.8.3 Section 8.2.3 of the FSAR states' that ESF -loads will be-sequentially connected to the offsite power supplies.to limit voltage dips.

It is inferred from this statement and the transformer characteristics shown on Figure 8-4 of the FSAR that sequential loading of the offsite power supplies may be a necessity due to high transformer impedance.

Discuss the effect on availability of offsite power resulting from connecting simultaneously all ESF loads to either Unit 3 startup transformer or to Unit 1 & 2 startup transformer under the maximim load operating condition of each transformer.

If the-consequences are unacceptable, describe the. provisions of your design that prevent this occurrence from happening to ass'ure that the availability of offsite power is maintained as required by GDC 17.

8.9

-It is not apparent from the information presented in Section 8.0 of the FSAR that the de ign capacity requirement of each redundant battery charger supply satisfy GDC 17. Criterion 17 statec that the onsite electric distribution system, shall have sufficient independence, redundancy, and testability to perform their safety function assuming a single failure.

In order to satisfy this-requirement of GDC 17 with regard to the. battery chargers, the capacity of each redundant battery charger supply should be based on the largest combined demands of the various steady-state loads and the charging capacity to restore the battery from the design minimum charge state to the fully charged state, irrespective of the status of the plant during which these demands occur.

Evaluate the design capacity requirement of each redundant battery charger supply against that required by GDC 17. Any exceptions to GDC 17 must be justified.

8.10 It is stated in Section 8.2s2.10 of the FSAR that the two separate -

battery rooms will be served by a connon exhaust system.

It is our concern that a single event such as fire and/or explosion in one room could be propagated to the other room resulting -in the loss of both redundant de emergency power systems. Unless you can demonstrate the capability of the ventilation system to withstand c single failure, we require that the design be modified to provide this assurance.

8.11 The response to Request 7.1.4 states that the criteria and bases for the installation of redundant safety cables and components are in accordance with Section 8.0 of the Proposed Guide for the Design and Installation of Cable Systems in Power Generating Stations, Draft 1, dated October 20, 1971. Although this document provides general guidance-to the designers in their development of wire and j

cable-installations, it is not specific enough. Amend your response to provide design information consistent with the detailed criteria listed below. t.ny exceptions to these criteria should be justified:

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In non-missile areas. a minimum free air separation of 5 feet vertical or 3 feet horizontal will be maintained between redundant safety cables or cable trays. When this minimum i -

spatial separation cannot be maintained, a physical barrier will be required.

i b.

Non-safety related cables from redundant safety buses (ac o.r dc)-

I will not'run together in the same tray'.

c.

A minimum free air separation of 6 inches in all' directions will be maintained between redundant power and control wiring on component panels and relay racks. When this minimum spatial separation cannot be maintained, a physical barrier will be provided.

d.

Cable splices in conduits and trays will not be allowed.

e.

State and justify the criteria governing the separation of redundant safety trays in missile producing areas.

It should be noted that hostile areas should be avoided-for the; location of Class IE equipment or circuits. Where such a location is unavoidable, only one system of redundant Class IE equipment or circuits should occupy the area.

i f.

With regard to cable tray loading and cable ampacity derating 1

factors, discuss the basis and acceptability of your criteria.

g.

Describe the environmental qualification testing requirements

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that have or will be used to assure that the safety-related cables located inside the containment will operate under the worst conditions of combined temperature, pressure, humidity and radiation to which these cables will be subjected.

8.12 Insufficient infonnation has been presented in the FSAR to show.

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that the proposed diesel generator qualification tests will satisfy Regulatory Guide 1.9.

Provide the needed information or justify any exceptions.

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8.13 Insufficient information has been presented in the FSAR to permit evaluation of the capacity of the emergency station batteries.

In this regard, (1) identify 'all safety and non-safety-related loads and their respective battery sources, (2) provide ~the design criteria and bases which establish the adequacy of each station battery to provide power to all safety and non-safety loads assuming complete loss of ac, (3) state the operating time period capacity of each battery with all safety and non-safety loads connected to it, and (4) discuss the means provided for disconnecting the non-safety loads from their respective batteries and identify these loads.

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J i-10.0 STEAM AND POWER CONVERSION SYSTEM 10.2 The response to Request 10.2 indicates that the motor-driven emer-gency feedwater pump receives power from the 4160 V ESF bus 3A.

The proposed mode of operation is to trip the motor upon loss of power at the bus and manually restart it, if required, on restora-tion of power to the bus at the completion of the associated diesel generator 3A 30 second block-loading ' sequence.. provide information establishing the minimum acceptable time for manually connecting this motor to diesel generator 3A under steam line break accident conditions coincident with a failure in the steam-driven emergency feedwater pump. Also amend Section 8.0 of the FSAR to address the effects of this additional load on diesel generator 3A.to show that the capacity of this diesel generator is adequate to handle this pump load plus other required ESF loads under the worst steam line break accident condition.

10.10 It is not clear from the response to Request 10.10 that in the event of a steam line break, coincident with a single failure of a feedwater isolation valve (preventing valve closure by either automatic or manual means), whether the consequences of controlled continued feedwater addition to the affected steam generator are.

acceptable. Our evaluation of the, main ferdwater line isolation as presently described indicates that the uncontrolled feedwater addition can occur as a result of a single failure. Unless it 4

can be demonstrated that the consequences of this occurrence are acceptable, we require that the feedwater system be designed to assure the required isolation coincident with an active single failure.

i 10.14 The analysis of the steam line break accident indicates that isola-tion of the break is effected by immediate automatic closure of the turbine stop valves and in the event of their failure to close, isolation is accomplished by manually closing the steam block valves. As indicated in the FSAR, the turbine stop valves are '

not Seismic Category I nor are the control circuits of these valves of safety grade. We have concluded that no credit can be taken for these valves to isolate a steam line break.

It is also 4

not clear whether manual actuation is adequate to assure timely closure of the steam block valves under all postulated design basis events including seismic events with the consequential failure of non-seismic Category I fluid system piping connected to the steam generators. Unless you can demonstrate that the manual actuation is adequate to assure timely closure of the steam block valves under the worst steam line break condition, we require that the design provide for the automatic closure of these valves with instrumentation, control and electrical power systems satisfying IEEE 279 and IEEE 308 respectively.

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