ML17334B604

Safety Evaluation Accepting Proposed EAL Changes for Plant

ML17334B604
Person / Time
Site:	Cook
Issue date:	10/25/1996
From:	NRC (Affiliation Not Assigned)
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ML17333A612	List: ML17333A611 ML17334B604
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NUDOCS 9610290230
Download: ML17334B604 (8)

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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY VALUATION BY T E

IC OF NUCL AR CTOR EGU ATION ATED TO REV S

D E

RG NCY C

ON LE S

INDIANA C

GAN POWER CO A Y ONAL C.

COOK UCL AR ANT UN T NOS.

1 AND 2 OCKET NOS.

-315 AND 50-3 6

1. 0 INTRODUCTION By letter dated June 13,

1994, as supplemented by letters dated Harch 31,

1995, Hay 31,

1996, August 30,

1996, September 27,

1996, October 2,

1996, and October 25,

1996, American Electric Power Company (the licensee) proposed changes to the D.C.

Cook Nuclear, Plant emergency action levels (EALs).

Specifically, the licensee provided a proposed revision to the Donald C.

Cook Nuclear Plant Emergency Plan Section 12.3.5, "Emergency Classification System,"

emergency plan implementing procedure, PHP 2080.EPP. 101, and the "Donald C. Cook Nuclear 'Plant E-Plan Classification vs NUHARC/NESP-007 Deviation Basis Document" that described how the proposed EALs incorporated the guidance in NUHARC/NESP-007, "Hethodology for Development of Emergency Action Levels," Revision 2, January 1992.

The NRC has endorsed NUHARC/NESP-007 as an acceptable method by which licensees may develop site-specific emergency classification schemes.

2.0 BACKGROUND

The proposed revision to the D.C.

Cook emergency action levels (EALs) was reviewed against the requirements in 10 CFR 50.47 (b)(4) and Appendix E to 10 CFR Part 50.

Section 50.47 (b)(4) specifies that onsite emergency plans must meet the following standard:

"A standard classification and. action level

scheme, the bases of which include facility system and effluent parameters, is in use by the nuclear facility licensee..."

Appendix E (IV)(C) specifies that "emergency action levels (based not only on onsite and offsite radiation monitoring information but also on readings from a,number of sensors that indicate a potential emergency, such as pressure in containment and response of the Emergency Core Cooling System) for notification of offsite agencies shall be described....The emergency classes defined shall include (1) notification of unusual

events, (2) alert, (3) site area emergency, and (4) general emergency."

In Revision 3 to Regulatory Guide 1. 101, "Emergency Planning and Preparedness for Nuclear Power Reactors,"

the NRC endorsed NUHARC/NESP-007, Revision 2,

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"Methodology for Development of Emergency Action Levels,"

as an acceptable method for licensees to meet the requirements of 10 CFR 50.47 (b)(4) and Appendix E to 10 CFR Part 50.

The staff relied upon the guidance in NUMARC/NESP-007 as the basis for its review of the D.C.Cook EAL changes.

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The licensee organized the EAL tables into five recognition categories:

(1) Abnormal Rad Levels/Radiological Effluents (2) System Malfunctions (3) Natural/Destructive Phenomena (4) Hazards and Other Conditions Affecting Plant Safety (5) Fission Product Barriers The Fission Product Barrier category was sub-divided into three categories for the specific EALs related to each of the three fission product barriers:

I (1) Fuel Clad Barrier (2)

RCS Barrier (3) Containment Barrier Most of the proposed EALs conformed closely to the guidance.

However, some of the licensee's proposed EALs depart from the example EALs in NUMARC/NESP-007 or are site specific changes or/and additions.

The staff's evaluation of these variations is discussed below.

Deviation Pl No Teleperimeter monitor or automatic dose assessment EALs NUMARC example EALs AU1-3 and AU1-4 are:

3.

Valid reading on perimeter radiation monitoring system greater than 0.10 mR/hr above normal background for 60 minutes (for sites having telemetered perimeter monitors'.

4.

Valid indication on automatic real-time dose assessment capability greater than (site-specific value) for 60 minutes or longer (for sites having such capability'.

The licensee stated that it does not possess a telemetered radiation monitoring system or real-time automatic dose assessment capability and, therefore, did not include site-specific EALs for these examples.

This comment is also applicable to NUMARC example EALs AA1-3, AA1-4, AS1-2, and AG1-2.

These deviations are acceptable.

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C Eft Thermocouple Reading Table 4 in NUMARC/NESP-007, PWR EMERGENCY ACTION LEVEL FISSION PRODUCT BARRIER REFERENCE TABLE THRESHOLDS FOR LOSS OR POTENTIAL LOSS OF BARRIERS,"

contains an example EAL for the loss of the fuel clad barrier as indicated by Core Exit thermocouple greater than (site specific) degree F.

The licensee

did not include this EAL in its EAL scheme.

The NUMARC/NESP-007 guidance states that the site-specific value used for this EAL should correspond to the core cooling -

RED Critical Safety Function status.

The licensee included an EAL for the loss of fuel clad barrier based upon the Critical Safety Function Status (Core Cooling Critical Safety Function Status Tree - Red) and therefore will be able to identify the loss of the fuel clad barrier upon an elevated core exit thermocouple reading.

This deviation from the NUMARC guidance is acceptable.

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th 1gthdlgyy C tt tgd Honitor Table 4 in NUMARC/NESP-007, "PWR EMERGENCY ACTION LEVEL FISSION PRODUCT BARRIER REFERENCE TABLE THRESHOLDS FOR LOSS OR POTENTIAL LOSS OF BARRIERS,"

contains an example EAL for the loss of the fuel clad barrier as indicated by Containment Radiation Honitor reading greater than (site-specific) R/hr.

The NUMARC guidance states that the set point should be calculated assuming the instantaneous release and dispersal of the reactor coolant noble gas and iodine inventory associated with a concentration of 300 pCi/g dose equivalent I-131 into the containment atmosphere.

The licensee calculated the set point based upon the D.C.

Cook Core Damage Assessment Methodology which assumed 5 X fuel cladding damage based only on noble gas releases.

It did not include the instantaneous release and disposal of the reactor coolant iodine inventory associated with a concentration of 300 pCi/g dose equivalent I-131 into the containment atmosphere.

This calculational method will result in a conservative and consistent assessment of the degree of core damage during an event and therefore is acceptable.

Deviation ¹4 Deviation in Potential loss of Containment EAL based on core exit thermocouple readings The licensee used an EAL based on Core Cooling Critical Safety Function Status Tree - RED and Restoration procedures are not effective within 15 minutes in place of the NUMARC recommended EAL based on Core exit thermocouples in excess of 1200'F and restoration procedures not effective within 15 minutes; or, core exit thermocouples in excess of 700'F with reactor vessel level below top of active fuel and restoration procedures not effective within 15 minutes.

Since the condition "Core Cooling Critical Safety Function Status Tree RED" is equivalent to the condition of "Core Exit thermocouples exceed 1200'F or the CET exceed 700'F with reactor vessel level below top of active fuel," this deviation is acceptable.

Deviation ¹5'ontrol Room Evacuation NUMARC IC HS2 includes the EAL:

a.

Control room evacuation has been initiated.

b.

Control of the plant cannot be established per (site-specific) procedure within (site-specific) minutes.

The corresponding Cook EAL is:

Control Room evacuation has been initiated AND Control of the following processes is not expected to be established within 15 minutes

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Reactivity RCS Inventory

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SG Heat Sink The Cook EAL deviates from the NUMARC guidance by specifying the processes which need to be controlled rather than referring to the procedure which specifies these processes.

The Cook EAL meets the intent of the NUHARC guidance and therefore is acceptable.

Deviation ¹6 No EAL for the Potential Loss of Fuel Clad Barrier based on Core Cooling Criticality Safety Function Indication Table 4 in NUMARC/NESP-007, "PWR EMERGENCY ACTION LEVEL FISSION PRODUCT BARRIER REFERENCE TABLE THRESHOLDS FOR LOSS OR POTENTIAL LOSS OF BARRIERS,"

contains an example EAL for the potential loss of the fuel clad barrier as indicated by Critical Safety Function Status - Core Cooling Orange.

The licensee did not include this EAL in its EAL scheme.

The indication Critical Safety Function Status - Core Cooling Orange occurs when the reactor vessel water level indication is below 39X and the core exit thermocouples are greater than 700 F.

In place of the Critical Safety Function Status EAL, the licensee include separate EALs for each of these conditions (water level and core exit thermocouple temperature) such that either of the EALs would result in the fuel clad barrier being considered as potentially lost.

This deviation from the NUHARC guidance is acceptable.

Deviation ¹7 No Unusual Event Level EAL for Fuel Clad Damage based upon Radiation Monitor Readings The NUMARC EALs under IC SU4 are:

SU4 Fuel Clad Degradation.

I.

(Site-specific) radiation monitor readings indicating fuel clad degradation greater than technical specification limits.

2.

(Site-specific) coolant sample activity value indicating fuel clad degradation greater than technical specification limits.

The Cook IC/EAL corresponding to this NUMARC IC/EAL are:

S-7 Fuel Clad Degradation

Activity > 1.0 pCi/g'-131 dose equivalent for > 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> in the RCS

-OR-RCS activity > 100/E pCi/g The licensee's EAL scheme did not include a radiation monitor indication based EAL corresponding to the first example EAL under NUNARC IC SU4.

The licensee stated that a-radiation monitor EAL was not included because the Cook plant does not have, a failed fuel monitor.

This deviation from the NUHARC guidance is acceptable.

S te-s ecif'c EAL Ind'cation ¹I Seismic Event EAL NUHARC EAL HAl-I is:

HAl-1 (Site-specific) method indicates seismic event greater than Operating Basis Earthquake '(OBE).

The Corresponding Cook EAL is:

I.

Confirmed Seismic Event greater than plant operating basis earthquake as indicated by:

a.

Seismic instrument activations OR b.

Ground motion at plant recognized as an earthquake based on consensus of control room operators on duty AND 2.

Either a.

Visible major damage to structures,

systems, and components in vital area.

OR b.

Plant trip The Cook (site-'specific) method for detecting a seismic event greater than the OBE includes the condition based upon damage to equipment or a plant trip, in addition to the condition of seismic instruments readings.

This additional condition is indicative of a seismic event greater that the plant operating basis and therefore is acceptable.

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¹ ATWS NUNRC EALs under IC SGl are:

S62-I (Site-specific) indications.exist that automatic and manual scram were not successful AND SG2-2 Either of the following:

a.

(Site-specific) indications exist that the core cooling is extremely challenged OR, b.

(site-specific) indications exist that heat removal is extremely challenged.

The corresponding Cook General Emergency EALs for the Anticipated Transient without scram (ATWS) condition are:

l.

ATWS was NOT terminated by manual reactor trip from the control room

-AND-2.

Subcriticality AND Core Cooling CSFSTs are RED.

- OR-Subcriticality AND Heat Sink CSFSTs are RED.

The condition of "subcriticality CSFST red" occurs when the reactor power level is greater than 5X.

This is used as a site-specific indication of the power generation greater than safety system design which, in conjunction with indication of challenges to the core cooling or heat removal functions, indicates that a core melt sequence exists.

This site-specific EAL threshold meets the intent of the corresponding NUHARC EAL and therefore is acceptable.

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Addition ¹1 Added EAL for the Loss of the Fuel Clad Barrier The licensee added the following site-specific EAL for the Loss of the Fuel Clad Barrier:

Assessment of core damage greater than 5X clad failure The EALs specified in the NUMARC guidance for the loss of the fuel clad barrier are based upon 5X clad damage.

The licensee added this site-specific EAL.

This addition is acceptable.

Site-s ec fic AL ddition ¹2 Added EAL for the Loss of the Containment Barrier The licensee added the following site specific EAL for the Loss of the Containment Barrier:

Entry into ECA-1.2, LOCA OlJTSIDE CONTAINHENT ECA-1.2 is entered when.there is evidence of excessive radiation levels in the auxiliary building while a loss of reactor or secondary coolant is occurring.

This is a valid indication of the loss of the containment barrier and, therefore, this EAL is acceptable.

Unisolable breach of containment The licensee included this EAL because it was indicative of the loss of the containment barrier.

This EAL also encompasses the NUMARC EAL for the loss of the containment barrier, "Valve(s) not closed and downstream pathway to the environment exists."

This site-specific EAL is acceptable.

Site-s eci ic AL ddition ¹3 Added EAL for the Potential Loss of the Containment Barrier.

The licensee added the following site specific EAL for the Potential Loss of the Containment Barrier:

Containment hydrogen concentration greater than 0.5X AND key hydrogen control equipment (Containment air recirculation/hydrogen skimmer

systems, electric hydrogen recombiners OR igniters) inoperable This EAL is indicative of a condition where safety systems meant to protect the containment are required to operate but are inoperable and therefore is indicative of a potential loss of Containment.

This site-specific EAL is acceptable.

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Addition ¹4 Added EAL for Flooding The licensee added the following site-specific Alert level EAL under the category of destructive phenomena:

Flooding in a vital area affecting safety related equipment This EAL is consistent with other Natural or Destructive NUMARC based EALs that affect the vital area and which are classified at the Alert level.

Therefore this EAL is acceptable.

Site-s eci ic AL Additi n ¹5 Added EAL for Release of Radioactive Material or Increase in Radiation Levels Mithin Facilities

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The licensee added the following site-specific EAL:

Valid alarII on New Fuel Storage Vault area radiation oonitor The licensee is using the alarm setting on its New Fuel Storage Vault Area Radiation Monitoring (NFSV) as an EAL.

This EAL has been in the licensee's current approved EAL scheme in its Emergency Implementing Procedures.

This EAL is acceptable.

4.0 g)~C The proposed EAL changes for D.C.Cook are consistent with the guidance in NUNRC/NESP-007, with variations as identified and accepted in this review, and, therefore, meet the requirements of 10 CFR 50.47(b)(4) and Appendix E to 10 CFR Part 50.

Principal Contributors:

L.K. Cohen, PERB/NRR J.B. O'rien, PERB/NRR Date:

October 25, 1996