3F0895-16, Ro:On 950713,1 H non-emergency Rept Made Re Condition Suspected to Be Outside Design Basis of Plant.Based on Conclusions of Design Basis Evaluation,Rescinds 1 H non-emergency Rept (NRC Event 29062)

Ro:On 950713,1 H non-emergency Rept Made Re Condition Suspected to Be Outside Design Basis of Plant.Based on Conclusions of Design Basis Evaluation,Rescinds 1 H non-emergency Rept (NRC Event 29062)

ML20087H910
Person / Time
Site:	Crystal River
Issue date:	08/11/1995
From:	Hickle B FLORIDA POWER CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
3F0895-16, 3F895-16, NUDOCS 9508180242
Download: ML20087H910 (12)

Text

->

Florida Power CORPORATION thames reaar August 11, 1995 3F0895-16 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D. C. 20555

Subject:

NRC Event #29062

Dear Sir:

During a plant walkdown, the NRC's follow-up to Florida Power Corporation's (FPC)

Crystal River Unit 3 (CR-3) Service Water Self Assessment, an NRC inspector identified a condition suspected to be outside the design basis of the plant.

A Problem Report (PR-95-0125) was initiated, and at 1835 on July 13, 1995 a 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> non-emergency report was made to the NRC as directed by 10 CFR 50.72(b)(1)(ii)(B). This report was assigned the NRC Event #29062 (see Attachment 1).

The condition reported to the NRC comprised the shell side of a decay heat exchanger not having a relief valve for overpressure protection, if the cooling water was isolated from the heat exchanger (see Figure 1). Subsequently, a  ;

Design Basis Evaluation (NED95-0399) was performed which stated, in part, "The  ;

DC [ed. Decay Heat Closed Cycle Cooling System] and DH [ed. Decay Heat] heat '

exchangers are designed in accordance with applicable design basis codes, l standards, and regulatory requirements and are acceptable 'as designed'" (see l Attachment 2). .

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CRYSTAL Rh/ER ENERGY COMPLEX: 15700 W Power une St . Crystal River, Florida 344284706 e (904) 795 6486 A Fkwida Progress Company l 9508190242 950811 PDR ADOCK 05000302 i S PDR

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U. S.- Nuclear Regulatory Commission

1. [

3F0895-16~

Page 2 of 2 l 3

Based on the conclusions of the Design Basis Evaluation, FPC hereby rescinds the l 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> non-emergency report (NRC Event #29062). Should you have any questions  !

concerning the engineering evaluation, please contact Brian Gutherman, f

. Supervisor, Nuclear Engineering Design at (904) 795-6486 extension 3325. '

Sincerely, l

']25 /.4 $[da -

B. J. Hickle, Director Nuclear Plant Operations ,

JAF:ff Attachments xc: Regional Administrator, Region II i Project Manager, NRR _ l Senior Resident Inspector l

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\ ei:rida INTEROFFICE CORRESPONDENCE Power Nuclear Engineerine Desien NA1E 240-3325 CORPORATION OFFICE MAC TELEPHONE i l

SUBJECT:

PR-95-0125, Corrective Item Step J - Design Basis Evaluation l

To: S. Chernenko DATE: July 24,1995 NED95-0399 This correspondence is being transmitted to you to provide you with the results of the above subject evaluation. The results of the evaluation are summarized below for your information.

Per ASME Section VIII, Division 1, UG-125,1968 edition, the heat exchangers for the Decay Heat Closed Cycle Cooling System (DC) are required by code to have pressure relief devices installed to protect the vessel, irrespective of the size or pressure of the vessel, in accordance with the requirements of UG-125 through UG-134. The installation of the relief capability need not be supplied by the vessel manufacturer. Relief capability may be installed within the inlet or outlet piping, between the inlet and outlet isolation valve (s) and the heat exchanger, in lieu of providing relief capabilities at the vessel itself.

As a result, the vessel manufacturer was not required nor under any obligation by code to provide relief capabilities at the vessel.

Per flow diagram, FD-302-631, sheets 1 and 2 of 3, closure of DCV-5 and DCV-7 for DHHE-1A; and, closure of DCV-6 and DCV-8 for DHHE-1B would isolate these heat exchangers from the relief valves installed within the remainder of the DC piping system.

During isolation of the heat exchangers, pressure relief would not be provided for these heat exchangers as required by the above referenced code requirements unless one of the two available vent valves were opened. Additionally, the existing pressure relief arrangement within the DC piping system, at first glance, does not appear to be in  ;

compliance with the above code requirements, as pressure relief capabilities located l

within the existing piping for DHHE-1A and DHHE-1B do not appear to be located between the existing isolation valves used for maintenance purposes for these heat exchangers, DCV-5 and DCV-7 for DHHE-1 A; and, DCV-6 and DCV-8 for DHHE-1B.

The existing DC System piping arrangements provide relief capabilities for the remaining 1 components within the DC System in accordance with the requirements of the ASME Codes (ie: relief valves are currently installed between the inlet isolation valves for all heat exchangers and pumps). The arrangement for DHHE-1A and DHHE-1B was designed to provide a minimum and maximun. cooling water flow to the heat exchangers l

by automatic valve positioning of DCV-17 and DCV-177 for DHHE-1 A or DCV-18 and {

DCV-178 for DHHE-1B, the outlet control valves nearest each heat exchanger and the bypass control valves for these heat exchangers. This arrangement prevents " dead

./

, SFOs95-14

_ Mkachunent t

NED95-0399 '

Page 2 of 6 t

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' heading" and " pump , m out" of the 1;C System now within the DH heat exchangers, i eliminating the need for closure of the inlet and outlet isolation valves, DCV-5 and DCV-7 for DHHE-1A and DCV-6 and DCV-8 for DHHE-1B, when placing one or both 'of  !

these heat exchangers "out-of service" or in " stand-by service"during normal plant operation. This design arrangement eliminates the need for closure of the inlet and outlet  !

isolation valves, DCV-5 and DCV-7 for DHHE-1 A; and, DCV-6 and DCV-8 for DHHE-IB, except during maintenance activities. This arrangement assures there is adequate ' l cooling . water now through the heat exchangers when the heat exchangers are out of service or in stand-by service (ie: Decay Heat Removal System is isolated), preventing ,

tube fouling on the cooling water side of these heat exchangers. ]

During maintenance periods, when inlet and outlet isolation valves, DCV-5 and DCV-7 for DHHE-1 A; and, DCV-6 and DCV-8 for DHHE-1B, for these heat exchangers may-be closed for performing maintenance on the DC or DH side of these heat exchangers, l one of the two available heat exchanger vents must be opened, as a minimum, to prevent any potential for inadvertent over pressurization of the isolated heat exchanger due to thermal transfer from the remainder of the DC System piping or the heat within the tube bundles from the DH System. This should occur whether the tube side has been isolated  ;

or not. Vents and drains are provided at the heat exchangers and must be used for this I purpose.

The design pressure for the shell side is 100 psig (cold) and 487 psig (hot) for the tube side of these Decay Heat heat exchangers. The design temperature for both is 300 -i degrees F.  !

As part of this evaluation, plant procedure OP-404, " Operating Procedure For The Decay Heat Removal System (and DC System)", was reviewed. Per the requirements of this procedure, inlet and outlet isolation valves DCV-5 and DCV-7 for DHHE-1 A and DCV-6 ,

and DCV-8 for DHHE-1B, ate not closed during normal plant operation of these >

systems, to include " initial filling and venting operations of the DHCCC System"  !

contained within section 4.2 of this procedure; and, " isolation ~ and restoration of individual decay heat pumps and heat exchangers", contained within section 4.14 of this l procedure. Placing either of the heat exchangers, DHHE-1 A or DHHE-1B,'in " stand-by" service is accomplished using the flow controller for either DHHE-1 A or DFHE-1B,  !

DCV-177-MS for DHHE-1 A and DCV-178-MS for DHHE-1B. This is accomplished by -

placing either of the controllers in the "0" position (ie: " minimum cooling), which opens L the bypass valves DCV-177 for DHHE-1 A or DCV-178 for DHHE-1B, while placing the 1 outlet control valve nearest the heat exchanger (ie: DCV-17 for DHHE-1 A or DCV-18 for DHHE-1B) to the minimum cooling position, assuring that relief capability is provided during normal plant operation of these heat exchangers (ie: heat exchangers are not isolated during normal plant operation). Additional information is contained within ,

this procedure for temperature step changes, setting the flow requirements, etc. for these

3F0895-r 6 Attachmat 2 NED95-0399 Page 3 of 6 heat exchangers using the above referenced controllers. See OP-404 for additional information. Per OP-404, when these heat exchangers are removed from service or are in stand-by service, the Decay Heat Removal System (tube side) is isolated. This prevents the internal temperature on the cooling water side (DC System) from exceeding the temperature limitations contained within this procedure for operation of these heat exchangers when the flow control controllers, DCV-177-MS for DHHE-1A and DCV-178-MS for DHHE-1B, are set in the "0" position (ie: minimum cooling, and not isolated on the cooling water side of the heat exchangers).

Per NED review of OP-404, this procedure does not provide specific guidance as to what steps should be accomplished when one of these heat exchangers is taken out of service for maintenance. During maintenance activities, such as removal of internal fouling (ie:

cleaning) of these heat exchangers, isolation of the Decay Heat Removal System for the affected heat exchanger would be required. Isolation of DCV-5 and DCV-7 for DHHE-1 A and DCV-6'and DCV-8 for DHHE-1B would require sealed closure. The vents and drains for the removed heat exchanger would require opening for venting and draining of the shell side of the heat exchanger. These steps are implied throughout the procedure but are not specifically addressed, similar to what is provided for DCHE-1 A and DCHE-IB, the other heat exchangers contained within the DC System. Additional guidance may be required regarding the isolation of DHHE-1 A or DHHE-1B during the performance of maintenance activities to assure the there is no potential for over pressurization of the heat exchangers when the inlet and outlet isolation valves are closed in the event these heat exchangers are not immediately vented and drained.

Per the review of the above design of the system, the current arrangement provides for pressure relief capabilities in accordance with the requirements of ASME Section VIII, UG-125,1968 edition, to include Appendix M reouirements, for these heat exchangers during normal plant operation. Placing a heat exchanger in " stand-by" service during normal plant operation is accomplished by opening the DC System bypass control valve for the non-operational heat exchanger, DCV-17 for DHHE-1A and DCV-18 for DHHE-1B; and, placing the outlet control valve closest to the heat exchanger outlet in the minimum flow position, DCV-177 for DHHE-1A and DCV-178 for DHHE-1B (ie:

"0" position for controllers DCV-177-MS for DHHE-1 A and DCV-178-MS for DHHE-IB). During maintenance of the heat exchangers, when the DC System is isolated from the heat exchangers using DCV-5 and DCV-7 for DHHE-1A and DCV-6 and DCV-8 for DHHE-1B, a vent valve (and/or drain valve) must be opened to assure there is no potential for over pressurization of the isolated heat exchanger due to thermal transfer from the isolated Decay Heat Removal System. Since the Decay Heat Removal System is isolated, transfer of residual heat to the isolated heat exchanger may occur over a period of time and would not be instantaneous. During these periods of isolation for maintenance purposes, the requirements for relief capabilities for these heat exchangers are satisfied by opening one of the two available vent valves, eliminating the need for

.' 3F0895-16 Mtachmen 2 l NED95-0399 Page 4 of 6 specific relief capabilities in the form of a relief valve or rupture disc while the equipment is isolated for maintenance purposes.

From the above, the existing arrangement complies with the requirements of the initial design for the DH heat exchangers, DHHE-1A and DHHE-1B, as described within ASME Section VIII, Division 1, UG-125,1968 edition, for normal plant operation, provided the heat exchangers are isolated in accordance with the design of the system as stated previously as currently established by procedure (ie: OP-404). During maintenance activities, when the DC System is to be isolated by closing the inlet and outlet isolation valves for these heat exchangers, a vent valve or drain valve should be immediately opened to assure that any potential for over pressurization of the isolated heat exchanger is eliminated in the event the heat exchanger removed from service is not immediately l vented or drained for maintenance purposes.

Per ASME Section VIII, UG-125,1968 edition, Appendix M, Paragraphs UA-354 and UA-355, as referenced within UG-125(e) and UG-134, states that an isolation stop valve may be installed between the vessel and the pressure relieving device provided in the event the isolation of the relief device from the vessel is so accomplished to isolate the pressure source to the vessel. The existing arrangement for the DHHE-1 A and DHHE-1B meets the restrictions. During normal operation, the DC System outlet control valves and the bypass valves are repositioned to the "0" position (ie: minimum cooling) when the heat exchanger is not in service or is in stand-by service. During the performance of maintenance activities, when the DC System inlet and outlet isolation valves for these heat exchangers are closed and the Decay heat removal System is isolated, the pressure source for these heat exchangers is isolated. Since both the shell side and the tube side are designed for a temperature of 300 degrees F, and the normal function of the heat exchangers is to cool the RCS within the DH System from 280 degrees to 140 degrees F within 14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br />, thermal transfer (ie: thermal over pressurization of the heat exchanger) during the short period when one of the two heat exchangers is taken out of service for maintenance is unlikely (pressure and temperature sources isolated). l Established maintenance clearances provide an adequate means to meet the requirements j of Appendix M, Section UA-354, which states that (isolation valves installed between the pressure vessel and relief device) "it shall not be closed except by authorized personnel who shall remain stationed there during that period of the vessel's operation within which the valve remains closed, and who shall again lock or seal the stop valve (ie: isolation valve - added for clarity) in the open position before leaving the station". Per Enclosure 2, Checklist II of OP-404, Page 3 for DCV-5 and DCV-7; and, Page 4 for DCV-6 and DCV-8, these isolation valves are " sealed open" during normal plant operation as  ;

required by ASME Section VIII, Division 1, UG-125, Appendix M. i As a result of the above, the previously identified potential Design Basis Issue of not having relief valves installed on the shell side of the DH heat exchangers or between

]

,+ . ,. . - .. . . . . . . - . .. -. - - . . - .- -

g S 3F0895-76 Attaciument f I NED95-0399 ,

Page 5 of 6 the isolation valves DCV-5 and DCV-7 for DHHE-1A and DCV-6 and DCV-8 for - l DHHE-1B, is not a design basis issue. The DC System and the DH heat exchangers are  !

- designed in accordance with applicable design basis codes,--standards, and regulatory i requirements and are acceptable "as designed".

No further action is required for this issue. The Corrective Action Plan for this problem ,

report is not needed nor required and will not be developed per this correspondence. We {

recommend voiding PR95-0125 and retraction of the NRC report generated for PR 95-1025.

A copy of this correspondence will be transmitted to the System Engineer for any follow up action with operations which may be deemed necessary concerning additional guidance .

for isolating either DHHE-1 A or DHHE-1B while performing maintenance activities.

NED will initiate a design basis document change to incorpomte this correspondence into  !

the design basis document for the DH System, documenting the evaluation within a i design reference.

REFERENCES:

FSAR Sections: 6.1.2.3, 6.2.2.1, 9.4.2, 9.5.1.b, 9.5.2.2 and Table 9-9.

i (Revision 21) i Design Basis '!

Documents: EDBD 6/3, Enhanced Design Basis Document For The Decay Heat Removal System", Revision 5. ,

EDBD 6/6 Enhanced Design Basis Document For The Decay Heat Closed Cycle Cooling System", Revision 3. ~l i

9rocedures,  ;

Drawings, etc.: OP-404, " Operation of the Decay Removal System", Revision 92.  ;

FD-302-631, Sheets 1 and 2 of 3  !

i Codes, Standards, j Regulations: ASME Section VIII, Division 1,1968 edition, Paragraphs UG-125 i through 134, and Appendix M. .I i

l

-l l,

.f .3,F0895.;6 4gggg Page 6 of 6 If you have any questions or require additionalinformation, please contact R. E. Robbins at 240-3293. ,

[

/k R. E. Robbins, Project Engineer Nuclear Engineering De.ign s /-

M B. Gutherman, Supervisor  !

Nuclear Engineering Design cc: J. R. Maseda w/ attach B. J. Hickle w/ attach K. R. Wilson w/ attach '

M.W. Donovan w/ attach ~

D. A. Shook w/ attach S. A. Stewart w/ attach K. R. Campbell w/ attach  :

M. W. Donovan w/ attach i Records Management (DXREF = EQUIP 4-15-1) w/ attach I

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.' APPENDIX M Installation and Operation UA 350 Introduction feasible. There are also rules in regard to the (a) The rules in this Appendix are for general desi6n of discharge piping from safety and relief information only, because they pertain to the valves, which can only be general ir nature be-installation and operation of pressure ves- cause the design engineer must fit the scrange-sels, which are the prerogative and responsi- ment and proportions of such a system to the bility of the law enforcement authorities in those particular requirements in the operation of the states and municipalities which have made pro- equipment involved.

vision for the enforcement of Section Vill of the Boiler and Pressure Vessel Code. UA-354 Stop Valves Between Pressere-Relieving (b) It is permissive to use any departures sug- Device and Vessel '

gested her< in from provisions in the mandatory (a) A vessel, in which pressure can be parts 'of this Division of Section Villwhen granted generated because of service conditions, may by the authority havin8 legal jurisdiction over the have a full-area stop valve between it and its installation of unfired pressure vessels. pressure-relieving device for inspection and UA-351 Corrosios " Pair purposes only. When such a stop valve is (a) Vessels subject to external corrosion shall Provided, it shall be so arranged that it can be be so installed that there is sufficient access to locked or sealed opes, and it shall not be closed all parts of the exterior to permit proper inspection "c'Pt by an authorized person who shall remain of the exterior, unless adequate protection against stationed there during that period of the vessel,a corrosion is provided or unless the vessel is of Operation within which the valve remains closed, such size and is so connected that it may readily and who shall again lock er seal the stop valvein ,

be removed from its permanent location for the open position before leaving the station, inspec tion. OI A " * ** I *' 'Y (see Par. UG-132(cT) f r which the pressure on.".ginates from an outside (b) Vessels having manholes, handholes, or cover plates to permit inspection of the interior " fee exclusively may have individual pressure-shall be so installed that these openings are ac- relieving devices on each vessel, or connected to cessible any Point on the connecting piping, a on any one of the vessels to be protected. Under such an (c) In vertical cylindrical vessels subject to armagement, there may be a stop valve between corrosion, to insure complete drainage,the bottom ,

head, if dished, should preferably be concave to ""Y ".ssel and the pressure relieving devices, and this stop valve need not be locked open, Pre u m . provided it also closes off that vessel from the UA-352 Lrking on the Vessel source of pressure.

The marking required by this Division shall be so located that it will be accessible after instal. UA-355 StoP Valves on the Dische'E' Side of a Pressure-Relieving Device (See Par. UG-134(e).)

lation and when installed shall not be covered with ,

full *f** 81 P valve may be placed on the dis-insulation or other material that is not readily charge side of a pressure relieving device when removable (see Par. UG-116(i)). ,

its discharge is connected to a common header UA-353 Pressere-Relieving Safety Devices with other discharge lines from other pressure.

The general provisions for the installation of relieving devices on nearby vessels that are in pressure relieving devices are fully covered in operation, so that this stop valve when closed Par. UG-134. The followin6 Paragraphs contain will prevent a discharge from any connected details in arrangement of stop valves for shut- operating vessels from backing up beyond the off control of safety pressure.eelief devices which valve so closed. Such a stop valve shall be so are sometimes necessary to the continuous opera- arranged that it een be locked or sealed in either tion of processins equipment of such a complex the open or closed position, and it shall be locked nature that the shut-down of any part of it is not or sealed in either position only by an authorized 4 -.

286 L-.  : _ _ _ _ _ _