ML20141N120

Safety Evaluation Supporting Amends 115 & 98 to Licenses DPR-53 & DPR-69,respectively

ML20141N120
Person / Time
Site:	Calvert Cliffs
Issue date:	02/20/1986
From:	Office of Nuclear Reactor Regulation
To:
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ML20141N119	List: ML20141N118 ML20141N120
References
NUDOCS 8603030602
Download: ML20141N120 (10)

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT N05.115 AND 98 TO FACILITY OPERATING LICENSE NOS. DPR-53 AND DPR-69 BALTIM0RE GAS AND ELECTRIC COMPANY CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NOS. 1 AND 2 DOCKET N05. 50-317 AND 50-318 Introduction By applications for license amendments dated December 22, 1983 and March 26, 1984, as supplemented by letters dated March 21, 1985 and August 9, 1985, Baltimore Gas and Electric Company (BG&E) requested changes to the Technical Specifications (TS) for Calvert Cliffs Units 1 and 2.

The proposed amendments would revise provisions in the TS to allow use of the 4-inch post-accident hydrogen purge line for containment purge during normal operation.

The TS would be changed as follows:

(1) TS 3.6.1.8,

" Containment Vent System," which requires the containment vent valves (MOV 6900 and 6901) to be closed during reactor operation would be deleted upon initial operability of the Containment Radiation Signal isolation input to motor operated valves (MOVs) 6900 and 6901; (2) the isolation times for MOVs 6900 and 6901 would be decreased from less than or equal to 20 seconds to less than or equal to 15 seconds as required by TS 3.6.4.1, " Containment Isolation Valves;" (3) the notation at the end of TS Table 3.6-1 "ContainmentIsolationValves,"wouldbechangedtoreflectdelei.ionofTS 3.6.1.8; and (4) a requirement would be added to TS Table 3.6-1 to limit the use of the containment vent valves to containment pressure control, containment radioactivity control, and surveillance purposes.

System Description

The hydrogen purge system is described in Section 6.8.3, " Hydrogen Purge System," of the Calvert Cliffs Final Safety Analysis Report (FSAR).

The hydrogen purge, system piping was designed and installed per ASME Nuclear Class 2, seismic Category 1.

It consists of a 4-inch schedule 40 pipe, running from inside containment through the containment penetration and leading to the penetration room exhaust system.

Inside containment, the line contains a moisture separator (with fixed blades) and an automatic 1 solation valve, MOV-6900. Outside containment, the line contains an automatic isolation valve, MOV-6901 and a flow meter.

At the flow meter, the line reduces to a 2-inch diameter.

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The penetration room exhaust system, which discharges to the plant vent, is seismic Category 1 and uses continuously welded duct, drawing air from the penetration rooms and the hydrogen purge system. All of the components in this system are qualified to operate under post loss-of-coolant accident 1

(LOCA) environmental conditions.

High efficiency particulate, roughing, and charcoal filters are provided in the system. The following changes to the hydrogen purge system have been made, or will be made, to make tse system suitable for use as an operational containment purge path:

Remove line restriction - At the present time, BG&E plans to remove the 2-inch restriction at the flow meter, outside containment, and install 4-inch pipe and a new flow meter. This modification does not impact any analyses considered herein and thus completion of this modification is not required for operability of the proposed l

containment vent path.

Install additional isolation signal - The automatic isolation valvesMOVs6900and6901areclosedonaSafetyInjectionActuation Signal (SIAS).

BG&E will modify the valve isolation logic for MOVs 6900 and 6901 to add an additional isolation signal which will result in the valves closing on a high containment radiation signal.

4 This modification has been completed for Calvert Cliffs Unit 2.

Upon completion of the modification to the automatic valve isolation logic and receipt of permitting TS, BG&E will use the hydrogen purge system, redesignated as a containment vent, for operational control of containment pressure and airborne radiation. The containment vent would still be available as a hydrogen purge path although the hydrogen recombiners represent the primary post-accident hydrogen control capability.

Evaluation of Valve Operability Durira a Loss-of-Coolant Accident (LOCA)

Demonstration of operability of MOVs 6900 and 6901 particularly the ability ofthesevalvestocloseduringadesignbasisaccIdent,isnecessaryto assure containment isolation.

This demonstration of operability is required by Branch Technical Position (BTP) CS8 6-4 and SRP 3-10 for containment purge and vent valves which are not sealed closed during reactor operation.

The valves identified as the containment isolation valves in the Containment Vent System are as follows:

Valve Tag Valve Size Number (Inches)

Operator Valve Location i

1-MOV6900 4

Limitorque Inside Containment

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1-MOV6901 4

Limitorque Outside Containment i

2-MOV6900 4

Limitorque Inside Containment 2-MOV6901 4

Limitorque Outside Containment The valves listed above are 4-inch gate valves manufactured by the Velan Engineering Company equipped with Limitorque SMB-00-5 operators and used for venting containment.

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.B M E has provided operability demonstration information for MOVs 6900 and 6901 in their letters dated December 22, 1983, October 5, 1984, and April 8, 1985.

BME states in their April 8,1985 letter that the values for maximum pressure 2

t = 8 seconds, 19.0 ft break resultingfromaLOCArangefrom41.5psig(a)breakarea).-Themaximumpressure area) to 47.5 psig (in steam line break is 49.2 psig (at t = 65 seconds).

at t = 45 seconds, 2.0 ft resulting from a ma The valves will close within 25 seconds, assuming a pipe break coincident with a i

loss of offsite power. Thus, the maximum pressure acting against the closing l

valve will be approximately 45 psig, considering all pipe break cases.

Velan Valve Corporation test results are provided for valve closure and opening against a 60 psi differential pressure.

Velan Valve Corporation seismic stress analysis BB4-600 GL-300 describes the methodology used in the analysis and the combined load conditions assumed.

The licensee has demonstrated the ability of the 4-inch gate valves to close d

against a pressure differential of 50 psi with the performance test results provided by the Velan Valve Corporation.

The 60 psi differential test pressure provides adequate torque margin since the peak LOCA containment l

pressure assumed is 45 psi for a 25-second valve closure time. Actual valve closure time during the Velan test was under 10 seconds. The tests also demonstrate that the torque absorption rating of the operators is not exceeded.

The stress analysis for the 4-inch valve critical parts and interfacing j

hardware furnished as an attachment to the BME April 8,1985 submittal assumes a combination of seismic forces, differential pressure, stem thrust i

and torque, and gland packing friction loads.

Calculated stresses are compared to the ASME Boiler and Pressure Vessel Code allowable stresses and are shown to be less than the allowable stresses for parts analyzed. The staff finds the methodology used and the results summarized acceptable, i

Based upon the above, the staff concludes that, in the event of a design basis LOCA, MOVs 6900 and 6901 will maintain a degree of operability that is sufficient to assure containment integrity.

Electrical Override / Bypass Design Evaluation By letter dated February 25, 1980, the NRC issued criteria to B M E regarding electrical override / bypass for use in the NRC review of purge valves.

The following criteria were contained in the February 25, 1980 letter:

The overriding of one type of safety actuation signal (e.g., radiation) j should not cause the blocking of any other type of safety actuation signal (e.g., pressure) to the isolation valves.

The following definitions are given for clarity of use in this issue:

Override - the signal is still present, and it is blocked in order to 4

i perform a function contrary to the signal; Reset - the signal has come and gone, and the circuit is being cleared to return to the normal I

condition.

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Sufficient physical features (e.g., key lock switches) should be provided to facilitate adequate administrative controls.

The system-level annunciation of the overridden status should be provided for every safety system impacted when an override is active.

At least two diverse signals should be provided to initiate isolation of the containment ventilation system.

Specifically, containment high radiation, safety injection actuation, and/or containment high pressure should automatically initiate containment isolation.

The instrumentation and control systems provided to initiate containment isolation should be designed and qualified as safety grade equipment.

The overriding or resetting of the isolation actuation signal should not I

cause the automatic reopening of any isolation / purge valve e

By letter dated November 15, 1985, BG&E responded to our letter of February 25, 1980 as the above criteria are applicable to MOVs 6900 and 6901. Based upon the staff's review of BG&E's letter of November 15, 1985, it concludes 1

that MOVs 6900 and 6901 meet the intent of the requirements regarding electrical override and bypass for containment purge and vent valves.

Isolation Signal Evaluation NUREG-0737, " Clarification of THI Action Plan Requirements," Item II.E.4.2 requires, in part, that containment isolation systems conform to Standard Review Plan (SRP) 6.2.4 with regard to diversity of containment isolation signals. The requirements in SRP 6.2.4 regarding containment isolation signals are contained in Sections II.6.1 and II.6.m as follows:

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There should be diversity in the parameters sensed for the initiation of containment isolation to satisfy the requirement of General Design Criterion 54 for reliable isolation capability.

i To improve the reliability of the isolation function, which is addressed m.

in General Design Criterion 54, system lines which provide an open path from the containment to the environs (e.g., purge and vent lines which are addressed in Item II.E.4.2 of NUREG-0737 and NUREG-0718) should be equipped with radiation monitors that are capable of isolating these lines upon a high radiation signal. A high radiation signal should not be considered one of the diverse containment isolation parameters.

With regard to item "1" above, MOVs 6900 and 6901 are automatically isolated on a SIAS signal.

As indicated in Calvert Cliffs FSAR Section 7.3.2.2,

" Actuation Subsystems", a SIAS is generated as a result of either two-out-of-four pressurizer sensor channel trip signals (pressurizer pressure-low), two-out-of-four containment pressure sensor channel trip signals (containment pressure-high) or manual initiation from the control i

Based upon the above, the staff concludes that the isolation signals room.

for MOVs 6900 and 6901 have sufficient diversity.

-5 As indicated previously, a containment radiation signal (CRS) will be, or has been, added to the isolation logic for MOVs 6900 and 6901.

Since the staff believes that incorporation of the CRS signal in the valve isolation logic adds a substantial margin of safety to assure prompt valve closure, a condition will appear in the TS to prohibit use of the containment vent, during o)eration, until the CRS modification is complete. Based upon the above, tie staff concludes that provisions for the isolation of MOVs 6900 and 6901 on high radiation, in containment, are adequate.

Technical Specifications BG&E has requested several changes to the TS in order to utilize the proposed eration.

The most significant change containment vent path during reactor op/4 6.1.8 upon completion of the CRS involves the proposed deletion of TS 3 modification.

At the present time, TS 3/4.6.1.8 requires MOVs 6900 and 6901 to remain closed and isolated during reactor operation.

BG&E, in their letter of August 9,1985, has provided an analysis of the consequences of a design basis LOCA initiated with MOVs 6900 and 6901 in the open position.

The LOCA while venting accident analysis was performed assuming a 30-second release period commencing at time = 0.

This analysis considered realistic flow losses due to pipe friction, elbows, valves and the moisture separator. The resultant site boundary doses were 30.9 rem thyroid and 0.8 rem whole body. When these doses are added to the original calculations of LOCA site boundary doses (Chapter 14 of the Updated FSAR)lts the total doses are 124.9 rem thyroid and 3.0 rem whole body. These resu show substantial margin to the 25 rem whole body and 300 rem thyroid limits of 10 CFR Part 100, Section 100.11.

The NRC staff has reviewed the referenced BG&E calculation and concludes that the calculation is suitably conservative and the results are accep/4.6.1.8 should be deleted upon completion of the CRSAc table.

the requirements of TS 3 modification; the following footnote will appear in the TS as proposed by the, licensee:

"These requirements shall be deleted u on initial operability of the CRS isolation input to MOV-6900 and MOV-6901.p' BG&E has proposed that the required isolation time for MOVs 6900 and 6901, as contained in TS Table 3.6-1, be reduced from (less than or equal to) 20 seconds to (less than or equal to) 15 seconds. The NRC staff has reviewed i

BG&E's selection of a valve closure time of 15 seconds and agrees that it is consistent with the overall closure response time of 30 seconds assumed in the analysis as follows:

2.4 seconds for containment pressure buildup, instrument response and SIAS delay, 10 seconds for emergency diesel generator startup, and 15 seconds for valve stroke time. An additional margin of 2.6 seconds is included for conservatism / margin. Accordingly, the staff concludes that the proposed change to TS Table 3.6.-1 is acceptable.

j BG&E has proposed the following restriction on use of the containment vent to be incorporated in TS Table 3.6-1:

"(4)Containmentventisolationvalvesshallbeopenedforcontainment pressure control, airborne radioactivity control, and surveillance testing purposes only."

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This proposed change to the TS is consistent with the NRC staff position on containment venting, as stated in our letter to BG&E of April 22, 1985, and is acceptable.

Finally, BG&E has proposed the deletion of wording in TS Table 3.6-1 that requires MOVs 6900 and 6901 to remain closed during reactor operation per TS 3/4.6.1.8. This wording can be deleted since TS 3/4.6.1.8 will remain in effect until completion of the CRS modification. Accordingly, the proposed change to TS Table 3.6-1 is acceptable.

Environmental Consideration

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The NRC staff has evaluated the environmental consequences of normal and accidental releases of effluents as a result of utilizing the containment vent. An Environmental Assessment and Finding of No Significant Impact, associated with this action, was published in the Federal Register on January 8, 1986 (51 FR 791). --

Conclusion We have concluded, based on the considerations discussed above, that (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations, and the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.

Date: February 20, 1986 Principal Contributors:

P. Kapo K. Dempsey d

H. Garg D. Jaffe R. Wright

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U. S. NUCLEAR REGULATORY C00MISS20N l

J BALTIMORE GAS AND ELECTRIC COMPANY DOCKET N05. 50-317 A E 50-318 i

NOTICE OF ISSUANCE OF AE NDMENTS TO FACILITY OPERATING LICENSES i

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The U. S. Nuclear Regulatory Commission (the Commission) has issued Amendment Nos.115 and 98 to Facility Operating License Nos. DPR-53 and DPR-69, issued to Baltimore Gas and Electric Company (the licensee), which revised the Technical Specifications for operation of the Calvert Cliffs Nuclear Power Plant, Units 1 and 2 (the facility), located in Calvert County, Maryland. The amendments were effective as of the date of their issuance.

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The amendments revise provisions in the Technical Specifications (TS) to i

allow use of.the 4-inch post-accident hydrogen purge line for centainment purge during normal operation.

The TS are changed as follows:

(1)TS3.6.1.8, i

" Containment Vent System," which requires the containment went valves (NOV 6900 and 6901) to be closed during reactor operation will be deleted upon I

initial operability of the Containment Radiation Signal isolation input to

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i motor operated valves (MOVs) 6900 and 6901; (2) the isolation times for MOVs 6900 and 6901 are decreased from less than or equal to 20 seconds to less 1

than or equal to 15 seconds as required by TS 3.6.4.1, " Containment Isolation Valves"; (3) the notation at the end of TS Table 3.6-1, " Containment 3

Isolation Valves," has been changed to reflect deletion of TS 3.6.1.8; and i

(4) a requirement has been added to TS Table 3.6-1 to limit the use of the 3

containment vent valves to containment pressure control, containment i

radioactivity control,'and surveillance purposes.

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-g The epplications for the amendments comply with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations. The Commission has made appropriate 4

findings as required by the Act and the Commission's rules and regulations in 10 CFR Chapter I, which are set forth in the license amendments.

Notice of Consideration of Issuance of Amendments and Opportunity for Prior Hearing in connection with this action was published in the FEDERAL REGISTER on March 11, 1985 (50 FR 9733) and December 13,1%5 (50 FR 50973).

No request for a hearing or petition for leave to intervene was filed following this notice.

The Commission has prepared an Environmental Assessment and Finding of No Significant Impact.related to the action and has concluded that an environcental impact statement is not warranted because"there will be no environmental impact attriiDutable to the action significantly beyond that which has been predicted and described in the Commission's Final Environmental Statement for the facility dated April 1973.

For further details with respect to the action see (1) the applications for amendments dated December 22, 1983 and March 26,1984,(2) Amendment Nos.

115 and 98 to Facility Operating License Nos. DPR-53 and DPR-69, (3) the Commission's related Safety Evaluation dated February 20, 1986, and (4) the Environmental Assessment dated December 31, 1985. All of these items are available for public inspection at the Commission's Public Document Room, i

1717 H Street, N.W., Washington, D.C., and 4t the Calvert County Library, Prince Frederick, Maryland.

A copy of items (2), (3) and (4) may be obtained

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upon request addressed to the U. S. Nuclear Regulatory Commission, Washington,D.C.h0555, Attention: Director, Division of MdR Licensing-B.

Dated at Bethesda, Maryland, this 20th day of February,1986.

FOR THE WuCLEAR REGULATORY COMISSION nald C5e'Ts, Acting Director PWR Project Directorate 88 Division of PWR Licensing-B J

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I[p* "'%)g UNIT 2D STATE.5 NUCLEAR CEGULATORY COMMISSION y CA, ',

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e February E 193C e,.

DOCKET No, 50-317/318

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MEMORANDUM FOR:

HMupHUrXMM Rdes & Procedures Cranch I

Nen UXE E E E EXEttH4MX4 Division of Relf.s & teccrds MDB Rn 4030 FROM:

Othce of Nue: ear P.evetor Pega13t'en Divis100 of PWR Liccasing-B

SUBJECT:

CALVERT CLIFFS fi'JCLEAR POWER PLANT UNIT MJ551 & 2 One signed original of the Federa/ Begister Notlte )dmt.ified canow is ecciosed for yeu: t arrimhtai to the Oitice of the Federal Reg %ter for puhWon, Add:tior.31 conforme:d ccpies {

6 ) of tiit Not;da are ennmd: fcr your use.

Notice of Pecsipt of Application for Constrtxtion Permit (s) a1d Operating License (s).

U Nctice. of accipt of Partial Appiication for Ccnstruct,cn Perm:t(sf and Fac.:ity License (s): TV $ for Submission of Viens i

on Antitrust Wtters.

U Notice of Consideration of IsWance of Amendment ta F6c:lity Operatirgg Ucense.

t U Notice of Receip! of AppLation 'cr Facility Ucense(s): Notice of Availaoility cf App'icant's EnvironenentM 'Aeport: and Notice cf Considerat:cri of 1swance of F0cnity ticente(s) ar.d Natice of Oppor* unity tor Hearing.

U Notice of Availa'oiiity of HRO Oraft/ Final EnvWmental Statement.

U Notice of Limited Wyk Autnorizatio%

U Noticeof Avaiiability of Safety Evaivatic.n Peport.

U Not:ce of Icsuance cf Construction Ferrrat(s),

h Notice of Issuance of FacWty Opetating Ucenss(s) or Aroendment(s).

U Order.

Exemption, Notice of Granting of Relief.

Other:

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Office of Nuclear Reactor Regulation Ditision of PWR Licensing-B

Enclosure:

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