ML20237B539

Forwards Written Documentation of Background & Technical Info Supporting McGuire Units 1 & 2 Notice of Enforcement Discretion Request.Discretion from Enforcing TS SR 4.6.5.1b.3,requested

ML20237B539
Person / Time
Site:	Mcguire, McGuire
Issue date:	08/12/1998
From:	Barron H DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20237B541	List: ML20237B539 ML20237B572
References
TAC-MA3282, TAC-MA3283, NUDOCS 9808190026
Download: ML20237B539 (11)

Text

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n Duke Energy Corporation

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la v McGuire Nuclear Station l l

12700 Hagers Ferry Road Huntersville, NC 28078-9340 l II. B, barron ' (704) 875-4800 omCE l

. Vice Pmident (704) 875-4809 FAX August-12, 1998 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington', D.C. 20555' l 1

Subject:

Duke Energy Corporation McGuire Nuclear Station, Units 1 and 2 Docket Number 50-369 and 50-370 Notice of Enforcement Discretion (NOED) Request Ice Condenser Technical' Specification Surveillance Requirement 4.6.5.1b.3 TAC Numbers MA3282 and MA3283 Attached is the written documentation of the background and technical information supporting the McGuire Units 1 and 2 Notice of Enforcement Discretion (NOED) request. This.information was discussed with the~NRC staff in a telephone conference call on

' August 12, 1998.

'As discussed in detail in Attachment 1, McGuire is requesting discretion from enforcing Technical Specification Surveillance Requirement 4.6.5.lb.3. This Surveillance Requirement governs verification of ice condenser system components with respect to the accumulation of frost or ice. As shown in the attached justification, Duke Energy maintains that granting of discretionary enforcement in this case is in the best interests of nuclear safety.

This request for enforcement discretion was approved by the McGuire Plant Operations Review Committee (PORC) on August 12, 1998. ,

Should you have any questions concerning this information, please call M. R. Wilder at (704) 875-5362. .

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U.S. Nuclear Regulatory. Commission Page 2

August'12,L1998L

.Very'truly yours,

H.'B .

Barron,LJr.

mrw-Attachment-

. xcf(with attachment):

- L'.A.'Reyes

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-U.S. -Nuclear' Regulatory ' Commission

- Regional Administrator,.. Region II

! 101 Marietta St., NW,-Suite 2900 Atlanta,.'GA.30323

- S. Schaffer-

- NRC Resident Inspector McGuire Nuclear Station F. Rinaldi-

!: ~ ' Senior Project-Manager l U.S., Nuclear Regulatory Commission-

l. Office of Nuclear Reactor Regulation L

, One White Flint North,' Mail Stop 14E21

' Washington, D.C. 20555 R. M.LFry,: Director j

Division of. Radiation Protection:

State'Of' North-Carolina 3825 Barrett Drive-p ~Raleigh, N.C. ' 27609-7221 b y A__m__ u.. ._

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l U.S. Nuclear Regulatory Commission Page.3 August'12,.1998

~

H . B '. Barron,'being duly sworn, states that he_is Vice President'-  !

of McGuire. Nuclear Station; that he-is authorized on-the part of '

' Duke Energy Corporation to sign and file with the U.S. Nuclear Regulatory Commission revisions-to the; Facility Operating

-Licenses of.'McGuire Nuclear Station; and,'that all statements and matters. set forth herein are true and correct to the best of his knowledge.

l H.B. Barron, Vice President

' Subscribed:and' sworn to before me this 12th day of August 1998.

10s}md > Y. AlAcen #

Notary Public A d oraLo G.Erf

- My Commission Expires:

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.U.S.:NucleariRegul'atory Commission:

Page 4 '

August 12, 1998

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- bxc : :; B'. L . . Walsh ' . ( EC11C )

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M.S...Kitlan (CNS)

~L.A.Keller~ (EC050):

J.I. Glenn (MG02ME):

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to -.L.S. Davis (MG05SE). ~

!t :J.E. Burchfield (ONS: Reg-Compliance)

.G.H.; Savage ((EC06E)

G.B. Swindlehurst (EC11-0842)

..C.ME Misenheimer (EC08I)

R. F. .' Cole" (ECOSN) '

l R.J. Freudenberger (EC05N), i T.G. Becker'(PB02L)

R - P.M. , Abraham - (EC08I) -

R .' B . . Wliite (MG01VP) I R.T.' Bond-(ONO3SR)

R ~. L'. Bain .s(CN05SR)

K.L.1 Crane (MG01RC)

G.D. Gilbert:(EC05N)

.P.R. Newton -(PB05E)'

3 NSRB Supporte. Staff (EC05N) 4

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r Attachment 1 McGuire Nuclear Station, Units 1 and 2 L Request for Enforcement Discretion l Technical Specification 4.6.5.1b.3 Ice Condenser System Surveillance Duke Energy hereby requests that the NRC grant discretion in enforcing Technical Specification Surveillance Requirement 4.6.5.lb.3 and to allow the McGuire Units 1 and 2 ice condensers

to be considered operable without having to completely perform I this Surveillance Requirement. McGuire cannot inspect the lower inlet plenum support structures and turning vanes while the units are at power.without incurring significant dose to personnel performing the inspection. As demonstrated below, McGuire L maintains that the lower inlet plenum support structures and turning vanes are capable of meeting the acceptance criteria of this Surveillance Requirement based on post maintenance inspections at the conclusion of the last refueling outages (Unit 1 - June 1998, Unit 2- December 1997) and on the observed condition of accessible components on Units 1 and 2.

Upon determination that Surveillance Requirement 4.6.5.1b.3 was not being completely complie'd with, McGuire declared the Unit 1 and 2 ice condensers inoperable. This declaration was made on August 12, 1998 at 1405 hours0.0163 days <br />0.39 hours <br />0.00232 weeks <br />5.346025e-4 months <br />. The identification of the inoperability was made immediately following an NRC conference call to inform McGuire that the staff interpretation of Surveillance Requirement 4.6.5.lb.3 was that the flow passage

-surveillance inspection shall include the lower inlet plenum support structures and the turning vanes.

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1. Technical Specifications violated i

. i McGuire Units 1 and 2 are requesting enforcement discretion from Surveillance Requirement 4.6.5.lb.3 which states, "The ice condenser shall be determined OPERABLE at least once per 9 months by verifying, by a visual inspection of at least two l flow passages per ice condenser bay, that the accumulation of frost or ice on flow passages between ice baskets, past lattice frames, through the intermediate and top deck floor grating, or past the lower inlet plenum support structures and turning vanes l is restricted to a thickness of less than or equal to 0.38 inch. )

If one flow passage per bay is found to have an accumulation of frost or ice with a thickness of greater than or equal to 0.38 inch, a representative sample of 20 additional flow passages from the same bay shall be visually inspected. If these additional

flow passages are found acceptable, the surveillance program may proceed 'considering the single deficiency as unique and acceptable. M ore than one restricted flow passage per bay is evidence of abnormal degradation of the ice condenser. "

Failure to meet this Surveillance Requirement would constitute inoperability of the ice condensers for both Unit 1 and 2.

McGuire is therefore asking for NRC discretion in enforcing this particular Surveillance Requirement for those ice condenser components which are inaccessible during unit operation (the lower inlet plenum support structures and turning vanes) so that ice condenser operability is not dependent upon this portion of the surveillance being met.

2. Circumstances surrounding the situation Ice condenser system description The ice condenser's primary function is the absorption of thermal energy released abruptly in the event of a loss of coolant accident, for.the purpose of limiting the initial peak pressure in the containment. A secondary function of the ice condenser is the further absorption of energy after the initial incident, causing the containment pressure to be reduced to and held at a lower level for.a period of time. The sodium tetraborate solution produced by a partial meltdown of the ice absorbs and retains iodine released during the accident and serves as a heat transfer medium and neutron poison for cooling the reactor core following the postulated incident.

The main part of the ice condenser is a mass of sodium tetraborate ice stored in an annular chamber inside the containment shell. The ice is maintained in an array of vertical cylindrical columns. The columns are formed by perforated baskets with the space between columns forming the flow channels for steam and air. The baskets are assembled into a lattice framework to form a continuous column of ice. The ice condenser is contained in the annulus formed by the containment vessel wall and the crane wall circumferentially over a 300 degree arc.

Three. sets of insulated doors are located, respectively, along the lower crane wall, in the intermediate deck, and in the top l deck. If lower containment compartment pressure exceeds upper l

containment compartment pressure by more than one pound per ,

square foot as the result of an accident, the lower inlet doors will swing open and allow the evolved steam to flow into the ice !

condenser. The direction of steam flow is changed 90 degrees by turning vanes. The steam will condense on the ice and chilled

structures, but air will-pass'through the ice bed and open the intermediate and top deck doors, venting to the upper compartment and compressing the containment atmosphere. The lower inlet doors are spring loaded.to assure flow uniformity, while the intermediate and upper doors are held closed by gravity only.

During the accident, borax' solution mixed with condensed steam

!will leave the. compartment via the doors and floor drains. The  ;

solution will drain into the containment sump, where it will be available for residual core heat removal. Iodine released during the accident will be dissolved'and retained in the melted borax i solution.

Description of circumstances  ;

During an evaluation of Technical Specification Surveillance

. Requirements associated with an inspection of the ice condenser system at McGuire, it was determined that all aspects of

Surveillance Requirement-4.6.5.lb.3 are not being met. In

.particular, the surveillance was not being performed for the lower inlet plenum support structures, and the turning vanes. A missed surveillance was declared for both the McGuire Unit 1 and i 2 with the ice condenser systems (ice bed) being declared L _ inoperable on August-12, 1998 at 1405 hours0.0163 days <br />0.39 hours <br />0.00232 weeks <br />5.346025e-4 months <br />. The applicable ACTION-requirement states, L

l "With i the ice bed inoperable, restore the ice bed to OPERABLE status within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />. "

l The11ower inlet plenum support structures and turning vanes are located in lower containment, and lower containment is not usually accessed during power operation as a result of dose considerations. Dose rates in the lower ice condenser at power exceed 3.6 R/hr. McGuire therefore elected to pursue this request for enforcement discretion to allow continued operation

, of both Unit 1 and 2 until the next scheduled refueling outages,

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or earlier outage (s) of sufficient duration to perform the surveillance. This request is for the NRC to exercise discretion in enforcing Surveillance Requirement 4.6.5.lb.3 with respect to the lower. inlet plenum support structures and turning vanes.

3._The safety basis for the request, including the evaluation of theisafety significance and potential consequences of the proposed action.

?There are no safety consequences associated with this request.

McGuire believes, based on ice condenser post maintenance Inspections performed at the conclusion of the last refueling

outages (Unit 1 - June 1998, Unit 2- December 1997) and on observable conditions associated with inspections of the accessible Unic 1 and 2 ice condenser components, that the Unit 1 and 2 ice condensers would be able to completely meet Surveillance Requirement 4.6.5.lb.3. The McGuire ice condenser system engineer and maintenance lead both verified the lower inlet plenum support structures and turning vanes were observed 1 to be free of ice at the conclusion of the last refueling outages l for both Units. McGuire cannot perform all aspects of this surveillance with the Units at power. In particular, the lower inlet plenum support structures and turning vanes are inaccessible for inspection as a result of the high dose rates in lower containment. Approval of this request is also preferable from a safety standpoint to the transient cycle that would be incurred on Units 1 and 2 should they be required to be shut down to meet all aspects of this surveillance. The surveillance will be performed in entirety during the next refueling outages, or earlier outage (s) of sufficient duration to perform the surveillance.

McGuire believes that the Unit 1 and 2 ice condensers are currently fully capable of performing the required design function in the event of an accident. NRC granting of this request for enforcement discretion will not result in any unavailability of the ice condensers. It can therefore be j concluded that no accident probabilities or consequences as  !

delineated in the McGuire Probabilistic Risk Assessment will be adversely impacted.

4. The basis for the licensee's conclusion that noncompliance will not be of potential detriment to the public health and j safety and that neither an unreviewed safety question nor a l significant hazard consideration is involved. j NRC granting of this request for enforcement discretion will not have any adverse consequences from the standpoint of public health and safety. As indicated above, McGuire believes that the l_ Unit 1-and 2 ice condensers are capable of meeting all acceptance L criteria of. Surveillance Requirement 4.6.5.1b.3, were these surveillance able to be performed in entirety. The ice condensers are therefore fully capable of meeting all technical requirements for operability and is capable of performing all design functions. Granting of this request will allow continued operation of McGuire Units 1 and 2 until the next refueling outages, or earlier outage (s) of sufficient duration to perform the surveillance, when Surveillance Requirement 4.6.5.lb.3 can be performed in its entirety for each respective Unit. Duke Energy has determined that no changes will be required to the l

, -y McGuire Updated Final Safety Analysis Report in conjunction with this request for' enforcement discretion.

There are no significant hazards considerations associated with this request for enforcement discretion. This is demonstrated as ]

'f ollows :

This request for enforcement discretion does not involve a significant increase in the probability or consequences of an accident previously evaluated. Granting of this request will have no significant effect on accident probabilities or consequences. The ice condenser system is not an accident initiating system; therefore, there will be no impact on any accident probabilities by the granting of this request. McGuire

-believes that the ice condensers are fully capable of meeting the required design basis accident mitigating functions. Therefore, there will be no impact on any accident consequences.

This request for enforcement discretion does not create the l possibility of a new or different kind of accident from any '

accident previously evaluated. No new accident causal mechanisms are created as a result of the NRC granting of this request for enforcement discretion. No changes are being made to the plant which will introduce any new accident causal mechanisms. This request for enforcement discretion does not impact any plant systems that are accident initiators, since the ice condenser system is an accident mitigating system.

This request for enforcement discretion does not involve a significant reduction in a margin of safety. Margin of safety is related to the confidence in the ability of the fission product barriers to perform their design functions during and following an accident situation. These barriers include the fuel cladding, the reactor coolant system, and the containment system. The performance of these fission product barriers will not be impacted by the NRC's granting of this request. The ice condenser system is believed to be fully capable of performing as designed. No safety margins will be impacted.

5. The basis for the licensee's conclusion that the noncompliance l

will not involve adverse consequences to the environment.

This request for enforcement discretion will not result in any changes in the types, or increase in the amounts, of any effluents that may be released offsite. In addition, no increase in individual or cumulative occupational radiation exposures will be involved. Therefore, it can be concluded that the NRC's u__-________________

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z grantingioffthis request for enforcement discretion:will not-involve'any: adverse: consequences to the. environment.

a i 6.JProposed' compensatory measures

No

compensatoryfmeasures.are being proposed. This issue'does not' 1 create any safety concerns _which warrant compensatory measures-

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E7. Justification for the-duration of the non-compliance The' duration of'the' noncompliance is; based ~on the time until the

'first condition of a)-submitted-TechnicalfSpec'ification' changes are approved, or b)lthe:next scheduled refueling outage, orLc) earlier outage offsufficient duration to perform.the surveillance -

forieach McGuire' Unit'11and 2. During these respective outages, McGuire'willfperform Surveillance Requirement 4.6.5.1b.3'in its-entirety,-fornalltice condenser components 1 delineated in the Surveillance. As stated:in' items.3'and.'4, there is no. safety-

-significance ~or potential' detriment to the health and' safety of the.public.

8.' Statement.that the rectest has been approved byithe facility: 'I organization that normally; reviews safety.. issues.

LThistrequest was. reviewed and' approved by the.McGuire; Plant Operations Review Committee infa special meeting lon August-12, l 21998.

. j 9.'How one of'the;NOED criteria for appropriateEplant conditions il specifi'ed"in'SectionLB isLsatisfied.

g -This3 request is intended to avoid an undesirable unit shutdown-transient-as a result of' requiring compliance with the Technical ~ 4

Specifications.and, thus, minimize potential safety consequences -!

Pandfoperational risks. (Reference Pa'rt 9900:. Technical' Guidance, I Criterion' .B .1) - i

'10. if a. follow-up. license ~ amendment is required,-the NOED ~

request mdst include' marked-up TS'pages. showing the proposed TS l

[Q changes.

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The'McGuire Unit 1 and 2 marked-up Technical Specifications pages are' included with this request for-enforcement discretion.

1The~ follow-up; license amendment will be submitted by August 14, 1998.

11. A statement'that prior adoption'of approved line-item l

' improvements to the TS or theLITS would not have obviated the need for'the NOED. request.

McGuire. submitted its' Improved Technical Specifications conversion license amendment-to the'NRC on May 27, 1997. This amendment is_ presently undergoing NRC staff' review. LThe Improved Technical Specifications amendment relocates much of the detail concerning Surveillance: Requirement.4~.6.5.lb.3.to the Bases of

. .the Improved Technical Specifications,1but-itsl technical content is unchanged from that currently'containediin Surveillance

~Requiremen. e 4.6 5.lb.3. Prior adoption.of approved line-item improvements to the Technical Specifications or the. Improved.

Technical Specifications would therefore not have obviated the

<need.for this NOED request.

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CONTAINMENT SYSTEMS 3/4.6.5 ICE CONDENSER I'CE BED LIMITING CONDITION FOR OPERATION 3.6.5.1 The ice bed shall be OPERABLE with:

! a. The stored ice having a boron concentration of at least 1800 ppm l boron as sodium tetraborate and a pH of 9.0 to 9.5,

b. Flow channels through the ice condenser,

c. A maximum ice bed temperature of less than or equal to 27'F,

d. A total ice weight of at least 2,099,790 pounds at a 95% level 5 cf confidence, and

e. 1944 ice baskets.

APPLICABILITY: MODES 1, 2, 3, and 4.

ACTION:

With the ice bed inoperable, restore the ice bed to OPERABLE status within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUT-DOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

SURVEILLANCE RE0VIREMENTS 4.6.5.1 The ice condenser shall be determined OPERABLE:

a. At least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> by using the Ice Bed Temperature Monitoring System to verify that the maximum ice bed temperature is less than or equal to 27'F,

b. At least once per 9 months by:

1) Chemical analyses which verify that at least nine representative samples of stored ice have a boron concentration of at least 1800 ppm as sodium tetraborate and a pH of 9.0 to 9.5 at 20'C; 1

2) Weighing a representative sample of at least 144 ice baskets )

and verifying that each basket contains at least 1081 lbs of J ice. The representative sample shall include 6 baskets from each of the 24 ice condenser bays and shall be constitut ed of 9808t90050 9008t2" PDR ADOCK 05000369 p PDR; McGUIRE - UNIT 1 3/4 6-20 -Amentfixd No. 100-

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