submittal of response to request for additional information for … · 2015. 6. 22. · un#08-092...

Greg Gibson 250 West Pratt Street, Suite 2000Baltimore, Maryland 21201

Vice President, Regulatory Affairs

UniStarNUCLEAR ENERGY

10 CFR 50.410 CFR 52.79

December 19, 2008

UN#08-092

ATTN: Document Control DeskU.S. Nuclear Regulatory CommissionWashington, DC 20555-0001

Subject: UniStar Nuclear Energy, NRC Docket No. 52-016Submittal of Response to Request for Additional Information for the Calvert CliffsNuclear Power Plant, Unit 3RAI No. 34, Revision 0 - Control Room Area Ventilation System

Reference: John Rycyna (NRC) to George Wrobel (UniStar), "RAI No 34 SPCV 297 and RAINo 35 SPCV 296 (P)," email dated. November 20, 2008

The purpose of this letter is to respond to the request for additional information (RAI) identifiedin the NRC e-mail correspondence to UniStar Nuclear, dated November 20, 2008 (Reference).This RAI addresses the Control Room Area Ventilation System, as discussed in Section 9.4.1.1of the Final Safety Analysis Report, as submitted in Part 2 of the CCNPP Unit 3 CombinedLicense Application (COLA).

The enclosure provides our response to RAI 34, which includes revised COLA content. ALicensing Basis Document Change Request has been initiated to incorporate these changesinto a future revision of the COLA. There are no new regulatory commitments in thiscorrespondence.

If there are any questions regarding this transmittal, please contact me at (410) 470-4205 or Mr.George Wrobel at (585) 771-3535.

UN#08-092December 19, 2008

I declare under penalty of perjury that the foregoing is true and correct.

Executed on December 19, 2008

Greg Gibson

Enclosure: Response to RAI No. 34, Revision 0 - Control Room Area Ventilation System

cc: U.S. NRC Region IU.S. NRC Resident Inspector, Calvert Cliffs Nuclear Power Plant, Units 1 and 2NRC Environmental Project Manager, U.S. EPR Combined License ApplicationNRC Project Manager, U.S. EPR Combined License ApplicationNRC Project Manager, U.S. EPR Design Certification Application (w/o enclosure)

Enclosure

Response to RAI No. 34, Revision 0

Control Room Area Ventilation System

December 19, 2008

UN#08-092 - EnclosurePage 1

RAI Number 34, Revision 0

Question 09.04.01-1

The applicant's FSAR, Section 9.4.1.1, "Design Bases," states that "[t]he evaluation of theCCNPP Unit 3 toxic chemicals in Section 2.2.3 did not identify any credible toxic chemicalaccidents that exceeded the limits established in Regulatory Guide 1.78 (NRC, 2001). Nospecific provisions are required to protect the operators from an event involving a release of atoxic gas. As a result, toxic gas detectors and isolation are not required and will not be providedat CCNPP Unit 3." The U.S. EPR FSAR, referenced in the applicant's COL, in Tier 1, Section2.6.1 states that "[t]he CRACS [control room air conditioning system] maintains habitability ofthe CRE [control room envelope] areas in case of radioactive or toxic gas contamination of theenvironment." Please explain how this will be accomplished if no equipment for this purpose willbe supplied.

Response:

The evaluation of CCNPP Unit 3 toxic chemicals in FSAR Section 2.2.3 did not identify anycredible toxic chemical accidents that exceed the limits established in Regulatory Guide 1.78.No specific provisions are required to protect the operators from an event involving a release oftoxic gas. As a result, toxic gas detectors and toxic gas-related CRE isolation are not'requiredand will not be provided at the CCNPP Unit 3. The COL FSAR Sections 1.8.2, 6.4 and 9.4.1 willbe revised to reflect a departure from the U.S. EPR FSAR with respect to toxic gas protection.Additionally, an exemption request will be taken to the toxic gas protection in the U.S. EPRFSAR, Tier 1, Section 2.6.1.

COLA Impact:

CCNPP Unit 3 FSAR Sections 1.8.2, 6.4 and 9.4.1; and COLA Part 7, Departures andExemption Requests, will be updated in a future COLA revision, as shown on the followingpages.

The page markups reflect changes to the toxic gas monitor description provided in U.S. EPRFSAR Tier 2 Section 6.4 that were previously communicated to the NRC in the response to U.S.EPR RAI 89, Question 06.04-41. Changes involving COL applicant items will not beincorporated in the CCNPP Unit 3 COLA until they are docketed in the U.S. EPR designcertification application.

1AREVA NP, Inc., Response to U.S. EPR Design Certification Application RAI No. 89 (1179,1181), FSAR Ch. 6, e-mail dated October 2, 2008


FSAR 1.8.2 - Page Markup

1.8.2 Departures

The U.S. EPR FSAR includes the following COL Item in Section 1.8.2:

A COL applicant that references the U. S. EPR design certification will provide a listof any departures from the FSAR in the COL FSAR.

This COL Item is addressed as follows:

{The list of departures from the U.S. EPR FSAR is as follows:

Maximum Differential Settlement FSAR 2.5.4 and 3.8.5

Maximum Annual Average Atmospheric Dispersion Factor FSAR 2.3.5

Accident Atmospheric Dispersion Factor from 0 - 2 Hours for FSAR 2.3.4 and 15.0.3the Low Population Zone

Maximu'm Ground Water Elevation FSAR 2.4.12, 3.4.2, and 3.8.5

Technical Specifications (Setpoint Control Program, Limiting FSAR 16.0 and COLA Part 4Trip Setpoint Inequality Signs, Time Delays, Location ofLimiting Trip Setpoint, and Incorporation of Site-SpecificData)

Toxic Gas Detection and Isolation FSAR 6.4 and 9.4.1

Justification for these departures is presented in Part 7 of the COL application.}


FSAR 6.4 - Page Markup

6.4 Habitability Systems

This section of the U.S. EPR FSAR is incorporated by reference with the followingsupplements {and departures.

The U.S. EPR ESAR inclue the following cceptual desig;- f ;or;mation ;n S 4eo 6.:

The habitability systems protect the plant operators from the effetsnr of accidental

[[Detection of and protection from toxic gases -ancd haRZardousw cheiars.]

{For CCNPP Unit 3, detection of toxic gases and subsequent isolation of the CRE is notrequired and is not part of the desig-basis site-specific design. The Fesults evaluationof the CCNPP Unit 3 toxic chemicals in Section 2.2.3 did not identify any credible toxicchemical accidents that exceeded the limits established in Regulatory Guide 1.78 (NRC,2001). No specific provisions are required to protect the operators from an eventinvolving a release of a toxic gas. As a result, toxic gas detectors and isolation are notrequired tte*o gas release and will not be provided at CCNPP Unit 3.)

6.4.1 Design Basis

{This section of the U.S. EPR FSAR is incorporated by reference with the followinqdepartures:

The U.S. EPR ESRAR inldsthe following conceptual design information n Section 641

[[The GRE is proteGte•d fromA ha•a•-,rdous c .h.emicGal roleaso-s to pemit acress andoccupancy of the MGR-]

For CCNPP Unit 3, protection from hazardous chemical releases within the CRE is notrequired and is not part of the design basis. {The evaluation of the CCNPP Unit 3 toxicchemicals in Section 2.2.3 did not identify any credible toxic chemical accidents thatexceed the limits established in Regulatory Guide 1.78 (NRC, 2001). No specificprovisions are required to protect the operators from an event involving a release of atoxic gas. As a result, toxic gas detectors and isolation are not required and will not beprovided at CCNPP Unit 3.)

6.4.2 System Design

{No departures or supplements.l

6.4.2.1 Definition of Control Room Envelope

{This section of the U.S. EPR FSAR is incorporated by reference with the followingdepartures:


I InO I Vu . t-r P-N I iIU VV l IV TIVIIVVill g conceptual design information in So+ti Vii

6.4,.2.1

2-G W~RIw ;fi ts, air upply equipment and protecti•eclothing forF .rotection fromn| m w-I ,*, t• ,.•,

J i~11alLv•|v vi i DV•IVM• •VV•ii.

2SOB-MRA units contafin a iiuaf six hours of air SUPPly capacity [[as specsifiedby RG .78.]]

•&'| ........ i l ....... { •- IN

ni i onuvo ua a uau u uu UU mUaUioUn U -a Iar V.I I lUAV.Tiow

For CCNPP Unit 3, protection from toxic gases within the CRE is not required and is notpart of the site-specific system design. {The evaluation of the CCNPP Unit 3 toxicchemicals in Section 2.2.3 did not identify any credible toxic chemical accidents thatexceed the limits established in Regulatory Guide 1.78 (NRC, 2001). As a result,C-CNIPP 'Unit 3 does not Fr8quie the use of SCBAs to mitigate a toxic gas release nospecific provisions are required to protect the operators from an event involving arelease of a toxic gas.}

6.4.2.2 Ventilation System Design


The U.S. EPR ESAR includes the following conceptual design infrmation in Section

The CRACS ai•e located on the roof of Safeguard Buildings 2 and 3, to

prevent [[intrusion Of toxic gases or]] radioleogical contamin-ation.

[[Control room operatos are preteed from chlorine releases and other toxic

gass n accordance with RG 1.52, RG 1.78, and ASrE AG , (Reference 2).]]

The ventilation system can be operated in full mreirmulation mode without Outside

air makeup du''rg DBAs [[or events involving toxicgas-, releases.]]

Redundancsy for air cooling, Mitratien[[, and toxfic gas protection]] is provided by

Am^ vý il-v v 44-yV llml l ~ )I V l ) 1I V V • v I • V VIV V. /j

. ..... I.# . ...

The -oceuldsg nomto sadesdas flos

For CCNPP Unit 3, detection of toxic gases and subsequent isolation of the CRE is notrequired and is not part of the site-specific system design. {The evaluation of theCCNPP Unit 3 toxic chemicals in Section 2.2.3 did not identify any credible toxicchemical accidents that exceeded the limits established in Regulatory Guide 1.78 (NRC,2001). No specific provisions are required to protect the operators from an eventinvolving a release of a toxic gas. As a result, toxic gas detectors and isolation are notrequired and will not be provided at CCNPP Unit 3.]


6.4.2.3 Leak-tightness

{No departures or supplements.)

6.4.2.4 Interaction with Other Zones and Pressure-Containing Equipment


The U.S. EPR ESAR iniludoc the- foloIIng coI nceptual design infrmationi6.4.2.A.

The CRIM area is isolated and pressurzd, the event of an outside fire,[[external toxic gas releaso,]] smoke, and eceie conentra~tionms of carbonmnoxide orarbon dioxide-.

Upon detection of [[toxic gas]] o k dible or viual alarms are actuatedthe MGR-.

The CrRACS_ doe-ps not ineatwith air conditioning equipmnent sew'ing adjacentzones, minimizing the possibility of transferring [[toxic or]] radioactivegesitthe C;RE--

The conceptual design iaddessed ays fo llows:nA

For CCNPP Unit 3. detection of toxic gases and subsequent isolation of the CRE is notrequired and is not part of the site-specific system design. {The evaluation of the,C6CNPP, Unit 3 toxic chemicals in Section 2.2.3 did not identify any credible toxicchemical accidents that exceeded the limits established in Regulatory Guide 1.78 (NRC,2001). No specific provisions are required to protect the operators from an eventinvolving a release of a toxic gas. As a result, toxic gas detectors and isolation are notrequired and will not be provided at CCNPP Unit

6.4.2.5 Shielding Design

(No departures or supplements.)

6.4.3 System Operational Procedures

This section of the U.S. EPR FSAR is incorporated by reference with the followingsupplements fand departuresl.

The U.S. EPR ESAR includes the following COL Item in Section 6.4.3:

A COL applicant that references the U.S. EPR design certification will providewritten emergency planning and procedures in the event of a radiological orhazardous chemical release within or near the plant, and will provide training ofcontrol room personnel.



{Constellation Generation Group and UniStar Nuclear Operating Services) shall providewritten emergency planning and procedures for use in the event of a radiological orhazardous chemical release within or near the plant, and will provide training of controlroom personnel, prior to receipt of fuel onsite at {CCNPP Unit 3}.

Llhe U.S. EPR F lAR include the following conceptual de÷ig •irmation• in Setion

[[Upon detection of any hazardous chemicals in tho environment which have apotential fo-r infiltrationA ipt-hin the CRE boundar:. the cOntro roomR operator willtake protective mneasures witA9hin a short period- of timne fromn the initiation of thetoxic gas senseors anrd- alarm~s. The operators are not subjected to prolongodexposures during this time.]]

Storage pr Msosfr SCBAe and procedureBs fonr tho-ir -use allow operators tobegin using the SCBAs within a short period of timne after detection ofaradiological event [[Or a hazardous reease.]]

The conceptual design information is addressed as, follows:

For CCNPP Unit 3, detection of toxic gases and subsequent isolation of the CRE is notrequired and is not part of the site-specific system operation. {The evaluation of theCCNPP Unit 3 toxic chemicals in Section 2.2.3 did not identify any credible toxicchemical accidents that exceeded the limits established in Regulatory Guide 1.78 (NRC,2001). No specific provisions are required to protect the operators from an eventinvolving a release of a toxic gas. As a result, toxic gas detectors and isolation are notrequired and will not be provided at CCNPP Unit 3.}

6.4.4 Design Evaluations

This section of the U.S. EPR FSAR is incorporated by reference with the followingsupplements {and departuresl.

The U.S. EPR FSAR includes the following COL Item in Section 6.4.4:

A COL applicant that references the U.S. EPR design certification will confirmthat the radiation exposure of MCR occupants resulting from a DBA at a nearbyunit on a multi-unit site is bounded by the radiation exposure from the postulateddesign basis accidents analyzed for the U.S. EPR; or confirm that the limits ofGDC 19 are met.


{The main control room dose to CCNPP Units 1 and 2 from a CCNPP Unit 3 LOCA isless than 2.0 rem TEDE. This dose is well below the regulatory dose acceptancecriterion of 5 rem TEDE. The CCNPP Unit 3 Main Control Room (MCR) is betterdesigned and equipped for radiological exposure control. Therefore, a LOCA in CCNPPUnit 1 or 2, which already meets the acceptance criteria for the applicable control room,


will also meet the acceptance criteria for the CCNPP Unit 3 Main Control Room. TheCCNPP Unit 3 MCR is equipped with safety-related radiation monitors in the HVACintake ducts and would isolate in a timely manner. The CCNPP Unit 3 MCR HVACemergency filtration system design basis accident configuration is described in U.S. EPRFSAR 15.0.3.)

The U.S. EPR FSAR includes the following c.n..ptual din nformation and COL Itemin Section 6.4.4:

Habitability systems provide the capability to de~tect and protect personnel Withinthe CRE bounda:ries fro exteral fi÷re, smoke [[, toxir. gases]] and airborne;radisaet!'-ty.

A COL applicant that references the U.S. EPR design certification will evaluatethe results of the toxic chemical accidents from Section 2.2.3 and address theirimpact on control room habitability in accordance with RG 1.78.

This The Gcnceptual desig- n information and COL Item is addressed as follows:

{The evaluation of the CCNPP Unit 3 toxic chemicals in Section 2.2.3 did not identify anycredible toxic chemical accidents that exceed the limits established in Regulatory Guide1.78 (NRC, 2001). As a result, toxic gas detectors and CRE isolation is not required forCCNPP Unit 3.}

For CCNPP Unit 3, detection of toxic gases and subsequent isolation of the CRE is notrequired and is not part of the site-specific design. {The evaluation of the CCNPP Unit 3toxic chemicals in Section 2.2.3 did not identify any credible toxic chemical accidentsthat exceeded the limits established in Regulatory Guide 1.78 (NRC, 2001). No specificprovisions are required to protect the operators from an event involving a release of atoxic gas. As a result, toxic gas detectors and isolation is are not required and will not beprovided at f-i: CCNPP Unit 3.)

6.4.5 Testing and Inspection

{No departures or supplements.)

6.4.6 Instrumentation Requirements

This section of the U.S. EPR FSAR is incorporated by reference with the followingsupplements {and departures}.

The U.S. EPR FSAR includes the following con.eptual design inf•ormation and COL Itemin Section 6.4.6:

[[TLoxic chemicl whose release has the potential to affect control roomoperatoyrs are monitred by oxvic gas senors.r A list of nhemiclsr aRd theirIloatioRn is provided in Se••ti 2.2.11


A COL applicant that references the U.S. EPR design certification will identify thetype(s) of any Seismic Category I Class IE toxic gas sensors (i.e., the toxicchemical(s) of concern) necessary for control room operator protection.

This .onceptual design'i"fnForation and COL Item are is addressed as follows:

{The evaluation of the CCNPP Unit 3 toxic chemicals in Section 2.2.3 did not identify anycredible toxic chemical accidents that exceeded the limits established in RegulatoryGuide 1.78 (NRC, 2001). No specific provisions are required to Protect the operatorsfrom an event involvinq a release of a toxic gas. As a result, CCNPP Unit 3 does not

.r.r Seism.GcG ategory 1 •lass IE= toxic ga S.ensors toxic gas detectors andisolation are not required and will not be provided at CCNPP Unit 3.}

For CCNPP Unit 3, toxic gas sensors are not required and are not part of the site-specific instrumentation design. The evaluation of the CCNPP Unit 3 toxic chemicals inSection 2.2.3 did not identify any credible toxic chemical accidents that exceed the limitsestablished in Regulatory Guide 1.78 (NRC, 2001). No specific provisions are requiredto protect the operators from an event involving a release of a toxic gas. As a result,toxic gas detectors and isolation are not required and will not be provided at CCNPP

6.4.7 References

{NRC, 2001. Evaluating the Habitability of a Nuclear Power Plant Control Room during aPostulated Hazardous Chemical Release, Regulatory Guide 1.78, Revision 1, U.S.Nuclear Regulatory Commission, December 2001.}


FSAR 9.4.1 - Page Markup

9.4.1 MAIN CONTROL ROOM AIR CONDITIONING SYSTEM

{No departures or supplements.}

9.4.1.1 Design Bases

{This section of the U.S. EPR FSAR is incorporated by reference with the departuresdescribed below:

The U.S. EPR ES-AR inldsthe following conceptual desinifraini Section

The CRAGS pFro'des adequate protoction against radiation [[and hazardouschemicaal releases]] to pormnit access, to and occupancy of the control room-F un'der-acidentcnditions (GDC 10). [[Tecnrlro1ccpnypoeto

reu rmets meet the guidance of RG 1.7-8.]]

The- C-RA.CS maintains habitability of the CRE areas, du--ring a site radiological

The C-RACS2 outside air inaeiGapable of detecting radiation and smoke [[andtoxic chemicals]] (see Section 6.4.2.4). Associated moenitors actuate alarms nthe AAGR-.

[[Upon attinof the plant toxic gas alarm signal, the outside air intakedampers6 close automatically and the CRE air is automatically diverted i hreciWrculation mode without outside air.]]

For CCNPP Unit 3, detection of toxic gases and subsequent isolation of the CRE is notrequired and is not part of the design basis. {The evaluation of the CCNPP Unit 3 toxicchemicals in Section 2.2.3 did not identify any credible toxic chemical accidents thatexceeded the limits established in Regulatory Guide 1.78 (NRC, 2001). No specificprovisions are required to protect the operators from an event involving a release of atoxic gas. As a result, toxic gas detectors and isolation are not required and will not beprovided at CCNPP Unit 3.)

9.4.1.2 System Description

9.4.1.2.1 General Description

fThis section of the U.S. EPR FSAR is incorporated by reference with the departuresdescribed below.

The U.IS6. E=PR =S.A.R inclu1des the following conceptual design informtion in Section9.4.1.2.1 and associated Figure 9.4.1 :2:


• I FPI • J P 4Sensr~qs on theo o-utSide ai;r inle-t 16tcaant Iitoxic gas (refer to zsectI9n

i k • bb i

A ;A A4 ana3ll rag~ioainnii inmruion........ I .... JJ C,

[[TG Toxinc Gas S-ensorsj]

ThIs connceavtual desi informations addressed as fo'llows

For CCNPP Unit 3, toxic gas sensors are not required and are not included in thesystem description. {The evaluation of the CCNPP Unit 3 toxic chemicals in Section2.2.3 did not identify any credible toxic chemical accidents that exceeded the limitsestablished in Regulatory Guide 1.78 (NRC, 2001). No specific provisions are requiredto protect the operators from an event involving a release of a toxic gas.}

9.4.1.2.2 Component Description

[ClNPP Unit 3 departs from the U.S. ElPR FSAR as folInlo

(The resuits of the C-CN121 Unit 3 toxic. chI mA eGal u • t•innSAection 2242.3; 3 ddl1 nt9

identify any toxic- cnhemnicamats;-; oe~eapa M inf mits esmabooSnea In Reguiamor,' Wuas1.78. Ats a result, toxicgas detectors and ioatinae not required and will nOtbeprovided at -CCNPP2 U nit-3.)

{No departures or supplements.1

9.4.1.2.3 System Operation

{This section of the U.S. EPR FSAR is incorporated by reference with the departuresdescribed below.

The U.S. EPR F=S A *R includes the followirGA.1.2.273.

RGcocota des-iGn iRnformration; in Section

[[During a toxic gas, accident event, the CRAGlS is plaed wi fIll recirculaton

moede without an" outside afir mnakeup (refer to Section 6.4.2.20]]

[[Operation During a Toaxic Gas Event

Outside aiF r, iscntinuously moenitored for toXic gas by the toxic gas sen;Gsorloc-,ated at- the ai naks pon detection of a toxic gas- condition, audible andvisum-al alarms are actuateed inR the MGR.

Operation durin~g External Fire, Smonke Or ToGxic Gas Release]]

Operation during External Fire, Smoke [[or Toxic Gas, Reas]

In the event of an external fire, [[external t gas elease,] smk, oiveconcentration of CO or G02, eUtside air to the CRAGS is isolated manually eFautomatircall and- the s+stem operates ion full FreciUlati.on Mode without fresh amr•

This conceotual desian information is addressed as- fo-llo-Ws:


For CCNPP Unit 3, toxic gas sensors are not required and are not included in thesystem operation. {The evaluation of the CCNPP Unit 3 toxic chemicals in Section 2.2.3did not identify any credible toxic chemical accidents that exceeded the limitsestablished in Regulatory Guide 1.78 (NRC, 2001). No specific provisions are requiredto protect the operators from an event involving a release of a toxic gas.}

9.4.1.3 Safety Evaluation'

No departures or supplements.

9.4.1.4 Inspection and Testing Requirements


9.4.1.5 Instrumentation Requirements


9.4.1.6 References

{NRC, 2001. Evaluating the Habitability of a Nuclear Power Plant Control Room During aPostulated Hazardous Chemical Release, Regulatory Guide 1.78, Revision 1, U. S.Nuclear Regulatory Commission, December 2001.)


COLA Part 7, Departures - Page Markup

7.1.X (Toxic Gas Detection and Isolation)

(Affected U.S. EPR FSAR Sections: Tier I Section 2.6.1, Tier 2 Section 1.8, Tier 2Section 6.4, Tier 2 Section 9.4.1, Tier 2 Section 14.2.12.8.10, Tier 2 Chapter 16

Summary of Departure:

The U.S EPR FSAR Tier 1 Section 2.6.1 requires that the main control room airconditioning system maintain habitability of the control room envelope and ambienttemperature conditions inside the control room envelope during toxic gas contaminationevents. As a result, the U.S. EPR design provides a toxic gas alarm signal withautomatically closing air intake dampers. For CCNPP Unit 3, the toxic gas alarm signalis not required and protection from toxic gas contamination events is not part of thesite-specific design basis.

ScopelExtent of Departure:

This Departure is identified in CCNPP Unit 3 FSAR Sections 1.8, 6.4, and 9.4.1.

Departure Justification:

An evaluation of the site-specific toxic chemical hazards in CCNPP Unit 3 FSAR Section2.2.3 did not identify any credible toxic chemical accidents that exceeded the limitsestablished in Regulatory Guide 1.78. No specific provisions are required to protect theoperators from an event involving a release of a toxic gas. Therefore, detection of toxicgases and subsequent isolation of the Control Room Envelope (CRE) is not requiredand is not part of the CCNPP Unit 3 site-specific design basis.

Departure Evaluation:

This Departure, associated with the detection of toxic gas and automatic isolation of theControl Room Envelope, has been evaluated and determined to not adversely affect thesafety function.

Accordingly, the Departure does not:

1. Result in more than a minimal increase in the frequency of occurrence of anaccident previously evaluated in the plant-specific FSAR;

2. Result in more than a minimal increase in the likelihood of occurrence of amalfunction of a structure, system, or component (SSC) important to safety andpreviously evaluated in the plant-specific FSAR;

3. Result in more than a minimal increase in the consequences of an accidentpreviously evaluated in the plant-specific FSAR;

4. Result in more than a minimal increase in the consequences of a malfunction ofan SSC important to safety previously evaluated in the plant-specific FSAR;


5. Create a possibility for an accident of a different type than any evaluatedpreviously in the plant-specific FSAR;

6. Create a possibility for a malfunction of an SSC important to safety with adifferent result than any evaluated previously in the plant-specific FSAR;

7. Result in a design basis limit for a fission product barrier as described in the plantspecific FSAR being exceeded or altered; or

8. Result in a departure from a method of evaluation described in the plant-specificFSAR used in establishing the design bases or in the safety analyses.

This Departure does not affect resolution of a severe accident issue identified in theplant specific FSAR.

Therefore, this Departure has no safety significance.}

UN#08-092,- EnclosurePage 14

COLA Part 7, Exemptions - Page Markup

7.2.X (Toxic Gas Detection and Isolation)

(Applicable Regulation: 10 CFR Part 52

The U.S EPR FSAR Tier 1 Section 2,6.1 requires that the main control room airconditioning system maintain habitability of the control room envelope and ambienttemperature conditions inside the control room envelope during toxic gas contaminationevents. As a result, the U.S. EPR design provides-a toxic gas alarm signal withautomatically closing air intake dampers. For CCNPP Unit 3, the toxic gas alarm signalis not required and protection from toxic gas contamination events is not part of thesite-specific design basis.

Pursuant to 10 CFR 52.7 and 10 CFR 52.93, Calvert Cliffs 3 Nuclear Project and UniStarNuclear Operating Services request an exemption from compliance with the U.S. EPRFSAR Tier 1 and Tier 2 requirements associated with control room envelope isolation asa result of the toxic gas detection and alarm signal.

Discussion:

The U.S. EPR design includes toxic gas detection and alarm signals to actuateautomatic closure of the control room air intake dampers. The evaluation of toxicchemicals hazards in CCNPP Unit 3 FSAR Section 2.2.3 did not identify any credibletoxic chemical accidents that exceed the limits established in Regulatory Guide 1.78.The evaluation concluded that no specific provisions are required to protect theoperators from an event involving a release of toxic gas. So, toxic gas detection andsubsequent control room envelope isolation are neither needed, nor provided forCCNPP Unit 3. Therefore, this change will not result in a significant decrease in the levelof safety otherwise provided by the design described in the U.S. EPR FSAR.

The exemption is not inconsistent with the Atomic Energy Act or any other statute. Assuch, the requested exemption is authorized by law.

The CCNPP Unit 3 design does not require reliance on a toxic gas detection and alarmsignal to initiate automatic closure of air intake dampers and isolation of the control roomenvelope. An evaluation of the CCNPP Unit 3 toxic chemicals in FSAR Section 2.2.3 didnot identify any credible toxic chemical accidents that exceeded the limits established inRegulatory Guide 1.78. No new or different type of accident will be created that couldpose a risk to public health and safety.

The change does not relate to security and does not otherwise pertain to the commondefense and security. Therefore, the requested exemption will not endanger thecommon defense and security.

The special circumstancei necessitating the request for exemption is that it has beendemonstrated via analysis that the toxic gas detection and alarm signal to initiateautomatic closure of air intake dampers for the main control room envelope is notrequired, as previously discussed. Therefore, application of the rule is not necessary toachieve the underlying purpose of the rule.


This requested exemption does not require a change in the design described in the U.S.EPR FSAR. This exemption request is based on the site specific toxic hazardsevaluation and is requested only for CCNPP Unit 3.

For these reasons, Calvert CliffsNuclear Project and UniStar Nuclear OperatingServices request approval of the requested exemption from compliance with the U.S.EPR FSAR Tier 1 and 2 requirements associated with toxic gas alarms for the maincontrol room.)

submittal of response to request for additional information for … · 2015. 6. 22. · un#08-092...

Documents