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yw .g UNITED STATES" " NUCl. EAR REGULATORY COMMISSIONE

f WASHINGTON, D.C. 20555 0001

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION

RELATED TO A RE00EST FOR RELIEF FROM SECTION XI 0F THE ASME CODE

SOUTH CAROLINA ELECTRIC & GAS COMPANY

SOUTH CAROLINA PUBLIC SERVICE AUTHORITY

VIRGIL C. SUMMER NUCLEAR STATION. UNIT NO. 1

DOCKET NO. 50-395

1.0 INTRODUCTION

By letter dated July 26, 1994, as supplemented October 7,1994, and October 26,1994, South Carolina Electric & Gas Company (the licensee) submitted a requestfor relief from the requirements of Section XI of the American Society ofMechanical Engineers Boiler and Pressure Vessel Code (ASME Code or Code) forVirgil C. Sumer Nuclear Station, Unit No.1 (Summer Station). The licensee hasrequested relief from Section IWA-5242(a). This Section of the Code requiresthat insulation be removed from pressure retaining bolted connections for VT-2visual examination during system pressure testing for systems borated fear thepurpose of controlling reactivity.

2.0 EVALUATION

As an alternative to the Code requirement, the licensee proposes thefollowing:

- An initial inspection shall be performed each refueling outageimmediately following shutdown prior to RCS cooldown anddepressurization. This is a hands off inspection for evidence ofleakage. There will be no removal of protective covers, shields,or insulation at this time. This inspection is also performed tosatisfy the requirements of Generic Letter (GL) 88-05.

- Following plant cooldown and depressurization, the insulation willbe removed from pressure retaining bolted connections and the VT-2visual examination will be conducted. Any signs of leakage asevidenced by the presence of boric acid residues will bedocumented. If the inspection shows no signs of beric acidresidues, the insulation will be replaced following the completionof the inspection of the bolted connection. This inspection isalso performed to satisfy the requirements of GL 88-05.

- If the presence of boric acid residues is found, a maintenancework request or a nonconforming notice will be generated to

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perform further evaluation of the bolted connection. Correctivemeasures will be implemented as required by IWA-5250, CorrectiveMeasures. The insulation will not be re-installed on thosecomponents receiving corrective measures and the following testrequirements shall be performed upon plant startup.

- For Code Class I while in Mode 5 with the RCS filled and vented, a,

VT-2 will be conducted with the system at greater than 300 psig.,

If the inspection shows no signs of leakage, the insulation will ,

be replaced following tne completion of the inspection of thebolted connection. If the inspection shows that leakage is stillpresent, further corrective measures will be taken prior toreplacement of the insulation. The bolted connections will beexamined again with the insulation installed during the regularlyscheduled system pressure test at nominal system operatingtemperature and pressure as required per Table IWA-2500-1,Examination Category B-P, including a four hour hold time.

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- For the portions of the above named Code Class 2 systems insidecontainment, while in Mode 5 the required system pressure test '

shall be conducted at nominal system operating temperature andpressure with the insulation removed from bolted connections. Ifthe test cannot be performed at nominal system operatingconditions due to the exposure of test personnel. to unacceptable 1

heat stress levels, a VT-2 will be conducted with the system at i

greater than 300 psig. If the inspection shows no signs of )leakage, the insulation will be replaced following the completion '

of the inspection of the bolted connection. If the inspectionshows that leakage is still present, corrective measures will betaken per IWA-5250 prior to replacement of the insulation. The I

bolted connections will be examined again with the insulation Iinstalled during the scheduled system pressure test at nominal !

system operating temperature and pressure as required per Table !IWC-2500-1, Examination Category C-H, including a four hour hold i

'time. This examination will be performed following the completionof each refueling outage.

Basis for Relief

The licensee stated:

IWA-5242(a) specifies that insulation must be removed from pressure.

retaining bolted connections for VT-2 visual examination during the |'performance of system pressure testing for the following systems:

Reactor Coolant System, Charging and Volume Control System, SafetyInjection System, and Residual Heat Removal System.

Table IWB-2500-1 and IWC-2500-1 require that testing bc performed prior i

to startup at nominal system operating pressure and temperature. Thiswould require the removal and restoration of the insulation on systemcomponents (bolted connections) with operating temperatures of between290F and 650F.

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The removal and installation of insulation during the performance ofsystem pressure testing inside reactor containment presents thefollowing personnel hazards:

- Increased potential for heat stress since the containment ambienttemperature is between 100F and 120F

- Increased personnel safety hazards since ladders would have to beused to inspect many of the bolted connections and replace theinsulation. Temporary work platforms / scaffolding inside reactorcontainment are removed prior to entering Mode 4.

- Increased radiation exposure to test personnel since temporaryshielding, inside and outside reactor containment is removed priorto entering Mode 4.

System / component temperatures:

Reactor Coolant System (tested in Mode 3); 550 - 650F

Chemical and Volume Control System (tested in Mode 3); 290 - 500F

- The system pressure testing of those Code Class 1 and portions of-Code Class 2 systems which have insulated bolted connections areconducted in Modes 3 and 4. This would require an additionalheatup/cooldown cycle on the plant each refueling outage sinceinspected areas cannot be accessed with the plant at nominalpressure and temperature. This has the potential to add up to twodays to the critical path of the refueling outage.

- The alternative testing provides the equivalent acceptable lev'elof quality and safety as that provided by the Code. Theinspection of pressure retaining bolted connections and the VT-2visual examination at reduced temperature and depressurized willprovide equivalent indication of leakage as evidenced by thepresence of boric acid residue. The corrective measures providethe same level of protection to the health and safety of thepublic as current Code requirements. Finally, VT-2 visualexamination performed at reduced pressure with the insulationremoved, provides high level of assurance and reasonableverification that corrective measures were adequate to correctleakage discovered during the depressurized VT-2 visualexamination. Based on prior experience and operating history, ifa leak is still present following repair activities, the leakwould be of a magnitude such that leakage would be present withthe system at 300 psig. Any subsequent leakage at nominal systempressure would normally occur as a result of a prolonged inservicecondition and not as a result of improper correttive measures.This type of leakage would be identified as part of theinspections performed each refueling outage with the systemdepressurized and the insulation removed. The reduced pressureexamination, alore with the system pressure test performed

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utilizing a four hour hold time with insulation installed,provides an equivalent level of inspection as required by the Jcode. ;

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Staff Evaluation ||

In place of the Code requirements for VT-2 visual examination of bolted I

connections inside containment in specifically identified systems borated for l

the purpose of controlling reactivity, the licensee has proposed a number of )compensating actions. The primary action proposed is to remove the insulation I

following cooldown and depressurization and examine the bolted connection andthe insulation for any signs of leakage as evidenced by the presence of boricacid residues. Leakage from a bolted connection in the systems identified by

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this relief request would be identified either by technical specification !requirements on RCS leakage or by this alternative. The systems in this I

relief request are under normal system pressure during reactor operation and |leakage from borated systems through bolted connections would result in boricacid deposits or residues at or near the source of the leak. If the presenceof boric acid residues is found, corrective measures will be implemented inaccordance with IWA-5250.

As part of the alternative testing, the licensee has proposed to remove theinsulation from certain Code Class 2 bolted connections and perform a VT-2 )visual examination once each refueling outage. This is an increase in the i

frequency over the Code required frequency for Class 2 systems of once each |

inspection period (40 months). In addition, the licensee has committed to |perform the VT-2 visual examination at nominal operating pressure with the i

insulation installed following the completion of each refueling outage. Thisis also an increase in the frequency for this test over the Code requiredfrequency for Class 2 systems of once each inspection period.

For Class 1 bolted connections the licensee has proposed that the insulationwill not be re-installed on those components receiving corrective mcasures i

until a VT-2 visual examination has been performed with the system at a ;pressure of greater than 300 psig. For Class 2 bolted connections the |licensee has proposed that the insulation will not be re-installed on those '

components receiving corrective measures until a VT-2 visual examination hasbeen performed with the system at nominal operating pressure. If thepersonnel stay time for the repaired Class 2 connections is too short to allow Ire-installation of the insulation at nominal operating conditions, the VT-2 )will be performed with the system at greater than 300 psig. If leakage is |

found, further corrective measures will be taken. If leakage is not found,the insulation will be replaced following the completion of the VT-2 visualinspection of the bolted connection. The bolted connection will be examinedagain with the insulation installed during the regularly scheduled systempressure test, including a four hour hold time.

The licensee has not demonstrated that performing the VT-2 and reinstallingthe insulation on any repaired Class 1 bolted connections with the system at ahigher pressure than 300 psig would result in hardship or unusual difficultieswithout a compensating increase in the level of quality and safety.Therefore, it will be necessary for the licensee to perform the VT-2 visual

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examination of repaired Class I bolted connections at nominal operatingpressure. If the personnel stay time for the repaired Class I connections istoo short to allow re-installation of the insulation at nominal operatingconditions, the VT-2 may be performed with the system at a pressure of atleast 300 psig.

To justify long-term relief the licensee should provide information on eachbolted connection covered by the relief request.

Specifically, in a revised relief request the licensee should provide:

(1) a listing of all bolted connections covered by this relief requestincluding their size and location in the system and in the containmentbuilding

(2) for Class 2 bolted connections provide the nominal operating pressureand temperature in the system at the bolted connection,

(3) a summary of the repairs performed during the Fall 1994 refueling outageon Class 1 and 2 bolted connections covered by this relief request,

(4) the system pressure during the VT-2 of the uninsulated connection,

(5) the basis for the pressure at which the VT-2 was performed

(6) the effectiveness of each repair as demonstrated by the VT-2 and theabsence of boric acid residue at the next outage.

3.0 CONCLUSION

The licensee has presented information, as discussed above, on the examinationof bolted connections for boric acid residues, the increased frequency of

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testing of Class 2 systems, performance of a visual examinations of repaired '

connections with the insulation removed, and a visual examination after a fourhour hold time at nominal operating pressure with the insulation reinstalled.The staff has concluded that, for the current (fall 1994) refueling outage,the code requirements would result in hardship without a compensating increasein the level of quality and safety provided that the provision discussed abovefor examination of repaired Class 1 bolted connections with the insulationremoved is followed. Accordingly, the alternative, as modified by this safetyevaluation, is authorized in accordance with 10 CFR 50.55a(a)(3)(ii) for useduring the fall 1994 refueling outage.

Principal Contributor: E. Sullivan

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