ML20217D834

Safety Evaluation Authorizing Licensee Request for Relief RR-C2 for Plant,First 10-yr Interval Insp Program Plan

ML20217D834
Person / Time
Site:	Hope Creek
Issue date:	09/25/1997
From:	NRC (Affiliation Not Assigned)
To:
Shared Package
ML20217D830	List: ML20217D827 ML20217D834
References
NUDOCS 9710060150
Download: ML20217D834 (5)

Text

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gemastg g* t UNITED STATES g j NUCLEAR REGULATORY COMMISSION

' g WASHINGTON, D.C. 3046H001

% * * * * * /g SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO WELDING SA-351. GRADE CD4MCu MATERIAL

, PUBLIC SERVICE ELECTRIC AND GAS COMPANY 4

! ATLANTIC CITY ELECTRIC COMPANY i

HOPE CREEK GENERATING STATION i

DOCKET NO. 50-15.i

1.0 INTRODUCTION

The Technical Specifications (TSs) for the Hope Creek Generating Station

. (HCGS) state that the inservice inspection of the American Society of Mechanical Engineers (ASME) Code Class 1, 2, and 3 components shall be performed in accordance with Section XI of the ASME Boiler and Pressure Yessel Code (ASME Code) and applicable addenda as required by Title 10 of the Code of 1 Federal Reaulations (10 CFR), Section 50.55a(g), except where specific written relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(1).

The requirements of 10 CFR 50.55a(a)(3) state that alternatives to the may be used, when authorized by the NRC, if requirements of paragraph the proposed alternatives wou (g)ld )rovide an acceptable level of quality and(i) safety or (ii) compliance with t ie s)ecified requirements would result in hardship or unusual difficulties wit 1out a compensating increase in the level of quality and safety,

Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1, 2, and 3 components (including supports) shall meet the requirements, except the design and access provisions and the preservice examination requirements, set forth in the ASME i Code,Section XI, " Rules for Inservice Inspection of Nuclear Power Plant

! Components," to the extent practical within the limitations of design,

, geometry, and materials of construction of the components. The regulations require that inservice examination of components and system pressure tests conducted during the first 10-year interval and subsequent intervals comply with the requirements in the latest edition and addenda of Section XI of the ASME Code incorporated by reference in 10 CFR 50.55a(b) 12 months prior to the start of the 120-month interval, subject to the limitations and modifications a listed therein. The appitcable edition of Section XI of the ASME Code during the first 10-year laservice ins)ection (ISI) interval for the Hope Creek Generating Station (HCGS), is tie 1983 Editinn including the Summer 1983 Addenda. By letter dated March 17, 1995, the NRC authorized the use of ASME Code Case N-498-1, ' Alternative Rules for 10-year Systym Hydrostatic Testing for Class 1, 2 and 3 Systems," for HCGS.

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with an examination requireme(nt of Section XI of the ASME Code is notPursuant to 10 CF practical for its facility, information shall be submitted to the Commission in support of that determination and a request made for relief from the ASME Code requirement. After evaluation of the determination, pursuant to 10 CFR 50.55a alternative re(g)(6)(1), the Commission may grant relief and may impose endanger life,quirements thatcommon property, or the are determined to be defense and authorized security, by othenvise and are law, will not in the public intetest, giving due consideration to the burden upon the licensee that could result if the requirements were imposed.

In a letter dated July 15, 1997, Public Service Electric and Gas Company (PSE&G), the licensee, submitted to the NRC its request for relief from the requirement of ASME Code Case N-498-1, " Alternative Rules for 10-Year System Hydrostatic Testing for Class 1.-2 and 3 Systems," of a 4-hour hold time at nominal operating pressure to a reduced hold time during system pressure testing of an insulated system at HCGS. The NRC staff has revis ad and evaluated the licensee's request for relief from the requirement of the Code Case based on the supporting information provided for HCGS.

2.0 DISCUSS 10N Component Description Insulated portions of High Pressure Coolant Injection piping, HPCI turbine steam supply and exhaust lines, dan(HPCI) associated pump discharge drains and vents.

ASME Code Class ASME Section XI Class 2 and Class 3 components Examination Requirement of Code Case N-498-1 (Asstated)

ASME Section XI Code Case N-498-1 was approved for use at Hope Creek Generating Station by NRC letter dated March 17, 1995. Code Case N-498-1 allows a system pressure test to be performed at nominal operating pressure on Class 2 and Class 3 components as an alternative to the ten year system hydrostatic test required by ASME Code,Section XI, Table IWC-2500-1 Category C-H (for Class 2), and Table IWD-2500-1, Categories D-A, 0-B, and D-C (for Class 3). However, the system pressure test alternative provided by the Code Case requires a four hour hold time at nominal operating pressure before performing the required visual examination for components which are insulated. Since the components identified above are insulated, a four hour hold time would be required for this test. Therefore, a reduction in the four hour hold time is the requirement from which relief is being requested.

Licensee's Basis for Relief (Asstated) r'ursuant to 10 CFR 50.55a(a)(3)(ii), F.iE&G is requesting this relief on the basis that compliance with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

As part of the Emergency Core Cooling System (ECCS), the HPCI system is not required to operate during normal plant operation. However, the system is periodically tested in accordance with applicable requirements.

These periodic tests are conducted to verify the operability of the applicable components. The functional test of the HPCI pump and turbine normally includes about thirty (30) minutes of pues run time. In order to satisfy the hold time requirement of Code Case 1-498-1, the test would require a HPCI pump run in excess of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> (hold time plus examination time). Running the HPCI pump for this duration is not practical and represents an undue hardship on the facility without a compensating increase in the level of quality and safety.

Operating the HPCI pump for the period of time required to satisfy the four hour hold time would subject the facility to unnecessarily excessive j heat loads. Control of these heat loads would require the operation of additional ECCS subsystems to remove heat from the suppression pool.

Extended operation of the HPCI pump would also challenge the Technical Specification limitation on maximum suppression pool water temperature.

Hope Creek Technical Specifications require the suppression pool average water temperature to be maintained less than 105'F during testing which adds heat to the suppression chamber. Operating the HPCI pump for a period substantially longer than the system functional test could cause this temperature to be exceeded. If the suppression pool average water temperature exceeds 110'F, Technical Specifications require the reactor mode switch to be placed in the Shutdown position.

During normal plant operation, with the HPCI system in the standby condition, the HPCI pump discharge line is maintained continuously above atmospheric pressure by operation of the HPCI jockey pump. While this pressure is less than the nominal operating pressure required by Code Case N-498-1, it does provide assurance that any leakage at this lower pressure, if it is occurring, will migrate through insulation.

Removal of the insulation from the subject components in order to use the ten minutes hold time allowsI by Code Case N-498-1 would be equally burdensome. The costs associated with insulation removal and reinstallation, including resource diversion, radiation exposura and additional radwaste, are not justified by a compensating increase in the level of quality and safety.

0 Performing an HPCI system hydrostatic test would also be burdensome. A hydrostatic test would require installation of blank flanges and temporary pipe supports, and gagging or removal of relief valves. The time, costs and radiation exposure 'ncurred in carrying out a hydrostatic test would result in a hardship without a compensating increase in the level of quality and safety.

Licensee's proposed Alternate Examination (As stated)

The system pressure test described in Code Case N-498-1 will be conducted as required, except that a twenty minute hold time will be used in lieu of the four hour hold time requirement. The twenty minute hold period will allow time for potential leaks to migrate through the insulatten I without e,hallenging the lechnical Specification limitation on maximum l suppression pool water temperature.

l 3.0 EVALUATION The applicable ASME Code,Section XI, requires a 10-year system hydrostatic test for Class 2 and Class 3 pressure-retaining components. However, Code Case N-498-1 allows a system leakage test at nominal operating pressure in lieu of the Code-required hydrostatic test provided that the applicable hold time requirements are met (4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> for insulated systems and 10 minutes for uninsulated systems). The intent of the hold time requirement is to allow leakage to penetrate the insulation prior to the visual intpection. The HPCI system at HCGS is an insulated system and, therefore, the 4-hour hold time requirement applies. The licensee, however, contends that it is an undue hardship on the facility without a compensating increase in the level of quality and safety, to maintain a 4-hour hold time during pressure testing of the HPCI system due to excessive increase in heat load to the suppression pool from the exhaust steam of the HPCI turbine pump. The increase in heat load would challenge the TS limit on the suppression pool average water temperature of 105 'F. Hence, if the requirement of Code Case N-498-1 with regard to the 4-hour hold time is imposed, the increase in heat load to the suppression pool must be controlled by operating additional ECCS subsystems to remove heat from the suppression pool. Alternatively, removal of insulation for the sole purpose of performing the 10-year hydrostatic pressure test per Code Case N-498-1) with a 10-minute hold time, would resu(or leakage test lt in excessive radiation exposure to plant personnel, which would cause hardship without a compensating increase in safety.

f- The staff has determined that the proposed alternative examination by the licensee to maintain a 20-minute hold time at nominal operating pressure prior to performing the VT-2 visual examination, operational readiness due to the following:provides reasonable assurance of

The HPCI pump discharge line is continuously maintained above atmospheric prsssure by operation of the HPCI jockey pump, which would cause any l

leakage to eventually migrate through the insulation and be capable of detection.

The HPCI turbine supply piping from the steam admission valve at the inlet to the test. turbine Hence, any is pressurized steam with leakage from thesteam to the reactor pressure during the through insulatirn and will be detected. piping will eventually migrate The turbine exhaust piping is open to the suppression pool during operation.

In accordance with demonstration of an open flow path is requi.id to satisfy the hydrostatic test requirements.

hold time. This can be verified within the 20-minute

4.0 CONCLUSION

i Based on the information provided in the licensee's relief request No. RR-C2 for HCGS, the NRC staff concludes that it is a hardship without a compensatin increase in safety during pressure testing of the insulated HPCI system by I complying with either the Code-required 4-hour hold time that results in l adding excessive heat to the suppression pool or removal of insulation from

) the components to utilize the 10-minute hold time requirement, which is associated with a high radiation penalty.

Nevertheless the licensee's pressure prior to VT-2 visual examinationproposed alternative to maintain a 20 operational readiness of the subject compo,nents.prcvides a reasonable assurance of Therefore request for relief is authorized-for the HPCI system only, p,ursuant tothe licsnsee's

, 10CFR50.55a(a)(3)(ii).

Principal Contributor: P. Patnaik Date: september 25, 1997 I -