ML20206A292

Safety Evaluation Concluding That Proposed Changes to EALs for PBAPS Are Consistent with Guidance in NUMARC/NESP-007 & Identified Deviations Meet Requirements of 10CFR50.47(b)(4) & App E to 10CFR50

ML20206A292
Person / Time
Site:	Peach Bottom
Issue date:	04/20/1999
From:	NRC (Affiliation Not Assigned)
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ML20206A283	List: ML20206A280 ML20206A292
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NUDOCS 9904280124
Download: ML20206A292 (9)

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. # CEO p **. UNITED STATES s* NUCLEAR REGULATORY COMMIS810N WASHINGTON, D.C. 30006-0001

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION ON REVISED EMERGENCY ACTION LEVELS FOR PECO ENERGY COMPANY PEACH BOTTOM ATOMIC POWER STATION. UNITS 2 AND 3 DOCKET NOS. 50-277 AND 50 278

1.0 INTRODUCTION

By letter dated April 16,1998, as supplemented by letters dated November 16,1998, January 22,1999 and February 11,1999, PECO Energy Company (the licensee) proposed changes to the Peach Bottom Atomic Power Station (PBAPS), Units 2 and 3, emergency action levels (EALs). The NRC staff's review of these proposed changes against the regulatory requirements contained in 10 CFR Part 50 follows.

The proposed revision to the PBAPS Units 2 and 3 EALs was reviewed against the requirements in 10 CFR 50.47(b)(4) and Appendix E to 10 CFR Part 50.

The regulations at 10 CFR 50.47(b)(4) require that onsite emergency plans must ensure that "a standard emergency classification and action level scheme, the bases of which include facility system and effluent parameters, is in use by the nuclear facility licensee...". I Appendix E, Subsection IV.B specifies in part that ". . . These emergency action levels shall be discussed and agreed on by the applicant and State and local govemmental authorities..."

Appendix E, Subsection 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 the pressure in containment and the response of the Emergency Core Cooling System) for notification of offsite agsncies 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 staff endorsed NUMARC/NESP-007, Revision 2, " 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 forits review of the proposed PBAPS EAL changes.

ENCLOSURE 9904290124 990420 P l PDR- ADOCK 05000277 <

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2.0 EVALUATION The licensee provided Revisions D and D1 of the PBAPS Technical Basis Manual containing the initiating Conditions (ICs), EALs, and technical bases for the EALs utilized in procedure ERP-101," Classification of Emergencies."

Most of the proposed EALs conform closely to the guidance. However, several of the licensee's proposed EALs depart from the example EALs in NUMARC/NESP-007. The staff reviewed the licensee's justification for these deviations, as discussed belovv. The staff found the deviations to be acceptable. The evaluation of the deviations are grouped into the following categories: (1) deviations from NUMARC/NESP-007, e.g., NUMARC/NESP-007 example EALs not included in the licensee's EAL scheme, (2) site-specific indications, e.g., EALs which include unique thresholds or indications, and (3) site-specific additions, i.e., EALs not specified in the NUMARC/NESP-007 guidance which were included in the

, licensee's EAL scheme.

i Deviation #1 AU1-1 NUMARC/NESP-007 EAL AU1-1 is:

A valid reading on one ormore of the following monitors that exceeds the "value shown"(site-specrRc monitors) Indicates that the release may have exceeded the above criterion and Indicates the need to assess the release with (Site-speciRc procedure): \

(Site-speciRclist) i Note: If the monitorreading(s) is sustained forlonger than 60 minutes and the required assessments cannot be completed within this period, then the declaration must be made based on the valid reading.

The corresponding PBAPS EAL (EAL 5.1.1.a) is:

A valid reading on one or more of the following radiation monitors that exceeds two times the HiH! alarm setpoint value for >60 minutes North Stack, South Stack, Radwaste Discharge, Cooling Tower Blowdown AND Calculated maximum offsite dose rate using computer dose model exceeds .114 mRetrVhr TPARD [ Total Protective Action Recommendation Dose] OR .342 mrem child thyroid CDE based on a 60 minute average NOTE: if the required dose projections cannot be completed within the 60 minute period then the declaration must be made based on the valid sustained monitor reading.

The licensas iixeipereted the condition of dose assessment results into this EAL This is not specifically identified in the NUMARC/NESP-007 guidance but is implied in the " note" associated with this EAL. Including the dose assessment results, the EAL provides confirmation that the magnitude of the loss of control of radioactive materials exceeds the threshold for an Unusual Event declaration. Furthermore, the dose assessment results can be i

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used to determine whether the release exceeds the threshold for classifying at a higher emergency classification level. This deviation is, therefore, acceptable. The PBAPS EAL corresponding to NUMARC/NESP-007 EAL AA1-1 deviates in a similar manner and is also acceptable.

Deviation #2 Fission Product Barrier- Main Steam Line Break One of the NUMARC/NESP-007 EALs for the loss of the reactor coolant system (RCS) barrier is:

LOSS:

(site-speci6c) indication of a Main Steam Une Break PBAPS removed this EAL from the fission product barrier table because, if the main steam line isolates as designed, this condition does not constitute a loss of the RCS barrier. However, the licensee included this condition as an event-based EAL due to the potential dose consequences associated with this event. This is consistent with the recommendations provided in the industry-developed Questions and Answers on the NUMARC/NESP-007 guidance which was endorsed by the NRC in a letter dated June 10,1993. This deviation is, therefore, acceptable.

Deviation #3 Fission Product Barrier Matrix - Drywell Pressure One of the NUMARC/NESP-007 EALs for the loss of the RCS barrier based upon drywell pressure is:

Pressure GREATER THAN (site-specific) psig The corresponding PBAPS EAL (3.3-RC.2)is:

DrywellPressure > 2.0 psig and Indication of a leakinside drywell The PBAPS EAL for the loss of RCS based upon drywell pressure indication deviates from the NUMARC/NESP-007 guidance by including the condition " indication of a leak inside drywell."

The licensee added this statement to its EAL as a " human factor reminder to the Emergency Director that use of this EAL is for accident scenarios only." This was to prevent classifying in the situation where drywell pressure increase is due to a loss of drywell cooling. This deviation is, therefore, acceptable.

Deviation #4 HU4 NUMARC/NESP-007 IC HU4 is:

Confirmed Security Event Which Indicates a Potential Degradation in the Level of Safety of the Plant

4 4

One of the NUMARC/NESP-007 example EALs under this IC is:

Bomb device discovered within plant Protected Area and outside the plant Vital Area PBAPS did not include this under its Unusual Event Security IC but did include a similar EAL l under the Alert Level Security IC (8.1.2). A bomb discovered within the protected area meets the condition specified in the Alert Level Security IC, i.e., " Security Event in the Protected Area." Therefore, this deviation is acceptable.

Deviation #5 SU4 NUMARC/NESP-007 IC SU4 is:

1 Fuel Clad Degradation k The NUMARC/NESP-007 example EALs under this IC are:

1. (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 applicable modes specified for these EALs in the NUMARC/NESP-007 guidance are "all" modes.

The license provided the following EALs (1.1.1.b and 4.1.1) corresponding to EAL 1 above:

' SJAE Radiation (Olfgas Monitor) > 2.5x10' mRMr Main Steam Line HiHi Radiation (10xNFPB [ normal fullpower background])

The licensee restricted the mode applicability of these EALs to run, startup, and hot shutdown because these are the only modes in which these monitors will be valid indicators of fuel clad damage. The licensee included an EAL for coolant sampling (* Reactor Coolant activity >4 pCi/gm Dose Equivalent lodine 131") which is applicable in all modes. This deviation is, therefore, acceptable.

Deviation #6 SSS 1 NUMARC/NESP-007 IC SS5 contains the following EALs:

Loss of reactor vessel waterlevel as indicated by:

- Loss of all decay heat removal cooling ....

and

- (site-specific) Indicators that ths core is or will be uncovered.

i The corresponding PBAPS EAL (2.1.3) is:

- RPVlevel < -172" The PBAPS EAL deviates by not including the condition of the " loss of all decay heat removal cooling ...." This is acceptable because water level less than -172" (top of active fuel) is, by itself, indication of the loss of decay heat removal.

j Deviation #7 HA2-1 NUMARC/NESP-007 IC HA2 is:

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Fim or Explosion Affecting the Operability of Plant Safety Systems Required to Establish or Maintain Safe Shutdown.

The NUMARC/NESP-007 EAL under this IC is:

The ibliowing conditions exist:

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n. Fire or explosion in any of the following (site-speci6c) areas:

(site-specr6c) list AND

b. Affected system parameter frutocations show degraded performance orplant personnel report visible damage to permanent structures or equipment within the specthed area PBAPS developed the following EAL for this condition:

Fire or explosion which potentially makes Inoperable:

Two ormore subsystems of a safe shutdown system (Table B-2) ortwo ormore safv shutdown systerns orplant vitalstructures containing sak shutdown equipment and Safe shutdown systems orplant vital structure is required for the present operationalcondrhon The licensee used the condition of "Two or more subsystems of a safe shutdown system (Table 8-2) or two or more safe shutdown systems..." as indication that the magnitude of the fire is such to cause a significant degradation in the level of safety of the plant. The condition

" Safe shutdown systems or plant vital structure is required for the present operational condition" is used as indication that the fire is located in an area which may cause a significant degradation in the level of safety of the plant. The PBAPS EAL meets the intent of the NUMARC/NESP-007 EAL, i.e., to classify fire-events which may cause a potential or actual

substantial degradation in the level of safety of the plant. The site-specific indications used in the PBAPS EAL are intended to prevent classifying, as Alerts, fires whose magnitude or location does not result in a substantial degradation in the level of safety of the plant. This EAL is, therefore, acceptable.

Site-soecific Indication #1 AS1-1, AG1-1 NUMARC/NESP-007 EAL AS1-1 is:

Valid dose assessment capabilityIndocates dose consequences greater than 100 mR whole body or 500 mR child thyroni The licensee expresses its corresponding EAL (5.1.3) in terms of Total Protective Action j Recommendation Dose (TPARD) instead of the whole body dose specified in the NUMARC/NESP-007 guidance. TPARD is equal to Total Effective Dose Equivalent (TEDE) plus 4-day deposition dose and is equivalent to dose guidance in the Environmental Protection Agency's Protective Action Guide' (EPA PAG). This is standard PECO Energy Company j terminology and is included in the output of the computerized dose model MESOREM Jr. The PBAPS EAL meets the intent of the NUMARC/NESP-007 guidance and, therefore, is acceptable. This also applies to the licensee's EAL 5.1.4 (corresponding to NUMARC/NESP-007 EAL AG1-1). l Site-specific Indication #2 AA3-2 NUMARC/NESP-007 IC AA3 is:

Release of Radioactive Material orincreases in Radiation Levels Within the Facility That Impedes Operation of Systems Required to Maintain Safe Operations orto Establish orMaintain Cold Shutdown One of the example EALs under this IC (EAL AA3-2) is:

Valid (Site-specific) radiation monitorreadings GREATER THAN < site specihc> values in areas requiring infrequent access to maintain plant safety functions.

The corresponding PBAPS EAL (5.2.2.a) is:

Valid radiation level readings >5000 mR/hrin areas requiring infrequent access to maintain plant sakty functions as identified in procedure SE-1 or SE-10 and Access is required for sak plant operation, but is impeded due to radiation dose rates The PBAPS EAL deviates from the NUMARC/NESP-007 example EAL by including the condition *and access is required for safe plant operation, but is impeded, due to radiation

' EPA Manual of Protective Action Guides and Protective Actions for Nuclear incidents, EPA 400-R-92-001, May 1992 I l

I dose rates." However, this condition is included in the NUMARC/NESP-007 IC for this EAL and is included in the basis for the EAL in the NUMARC/NESP-007 guidance. The PBAPS EAL is consistent with the intent of the NUMARC/NESP-007 guidance and, therefore, is acceptable, i

Site-Soecific Indication #3 SUS NUMARC/NESP-007 EAL associated with IC SUS is:

1. The following conditions exist:

a. UnidentiSed orpressure boundaryleakage greater than 10 gpm.

OR

b. Identified leakage greater than 25 gpm.

The licensee's proposed EAL is (2.1.1):

The following conditions exist: .

Unidenti6ed Primary System Leakage > 10 gpm into the Drywell OR Identified Primary System Leakage > 25 gpm into the Drywell The proposed EAL appears to deviate from the corresponding NUMARC/NESP-007 EAL in that it does not refer to " pressure boundary leakage." The licensee indicated in its submittal that "There is no Peach Bottom EAL listed for pressure boundary leakage specifically since it is a subset of unidentified leakage. Peach Bottom Technical Specifications require a shutdown if any pressure boundary leakage is found." This is acceptable, in addition, the EAL includes the condition, " leakage into the drywell," which is not specified in the NUMARC/NESP-007 guidance. Measurement of the magnitude of RCS leakage is from indications related to containment sump conditions. Leakage outside of containment is identified from area temperatures or radiation monitors. These indicators are used in EALs which are included in the fission product barrier matrix. The PBAPS EAL meets the intent of the NUMARC/NESP-007 guidance and, therefore, is acceptable.

Site-Specific Indication #4 SA1-1 NUMARC/NESP-007 EAL SA1.1 is:

1. The following conditions exist:

a. Loss of power to (Site-speciSc) transformers.

AND

b. Failure of (Site-specific) emergency generators to supply power to emergency busses.

AND

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c. Failure to restore power to at least one emergency bus within 15 minutes from the time ofloss of both offsite and onsite AC power.

The PBAPS proposed EAL (6.1.2.b) is:

The following conditions exist:

Loss of Power to 2 and 3 Startup and Emergency Aux. Transformers and 343 Startup Transformer dNQ Failure to restore power to at least One 4KV emergency bus within 15 minutes from the time ofloss of both offsite and onsite AC power PBAPS EAL deviates from the NUMARC/NESP-007 EAL in that it does not include the second condition of the NUMARC/NESP-007 EAL, which is "b. Failure of (Site-specific) emergency generators to supply power to emergency busses." However, the condition " Failure to restore power to at least One emergency bus within 15 minutes from the time of loss of both offsite and onsite .AC power" can only occur if the emergency generators fail to supply power to the emergency buses. The PBAPS EAL is consistent with the NUMARC/NESP-007 guidance and is, therefore, acceptable.

Site-sDecific Indication #5 SA3-1 NUMARC/NESP-007 EAL SA3-1 is:

1. The following conditions exist:

a. Loss of(Site-specific) Technical Specification required functions to maintain cold shutdown.

AND

b. Temperature increase that either:

= Exceeds Technical Specification cold shutdown temperature limit OR  ;

• Results in uncontrolled temperature rise approaching cold shutdown technicalspecificationlimit. j The correspondir.g PBAPS EAL is:

Unplanned loss of all tech spec required systems available to provide decay heat removalfunctions and Uncontrolled temperature increase that either: l

- exceeds 200 *F (Excluding a <15 minute rise >200 *F with a heat removal function restored) or

- results in temperature rise approaching 200 *F (with no heat removal function restored)

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The licensee included the conditions " Excluding a <15 minute rise >200 *F with a heat removal funcbon restored" and "(with no heat removal function restored)" to prevent classifying events in which systems can or have been restored in a short period of time to control RCS temperature. Events where this restoration occurs do not warrant an Alert classifcation.

Therefore, this deviation is acceptable.

Sete-specific Addson #1 PBAPS added the following EAL (3.4-PC.5) to the fission product barrier as an indication of a potentialloss of the containment barrier; RPVlevelcannot be deterrrined and RPV Flooding cannot be established per T-116 The licensee added this EAL because under these conditions primary containment flooding would be necessary per their emergency operating procedure and one of the actions taken along with primary containment flooding is the venting of containment. Furthermore, this condition is indicative of a situation where the core cannot be adequately cooled such that a core melt accident may be in progress. This condition is indicative of a potentialloss of containment and this site-specific addition is, therefore, acceptable.

Site-soecific Addition #2 PBAPS added the following EAL (3.3-RC.5) to the fission product barrier as an indication of a potentialloss of the RCS barrier.

RPVlevelcannot be determined The licensee added this EAL because there is a potential for this condition to exist during a loss of coolant accident due to bo, ling in the reactor level reference legs. The licensee provided clarification in the basis for this EAL to limit its application to these type of events.

This site-specific addition is, therefore, acceptable.

3.0 CONCLUSION

The proposed changes to EALs for PBAPS are consistent with the guidance in NUMARC/NESP-007, and the identified deviations meet the requirements of 10 CFR 50.47(b)(4) and Appendix E to 10 CFR Part 50. Therefore, the proposed EALs are .

acceptable.

Principal Contributors: S. Roudier J. O'Brien l

Date: April 20,1999 1 1

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