PLA-6172, Proposed License Amendment for Constant Pressure Power Uprate - Supplement PLA-6172

Proposed License Amendment for Constant Pressure Power Uprate - Supplement PLA-6172

ML070890411
Person / Time
Site:	Susquehanna
Issue date:	03/22/2007
From:	Mckinney B Susquehanna
To:	Document Control Desk, NRC/NRR/ADRO
References
PLA-6172
Download: ML070890411 (7)

Text

Britt T. McKinney Sr. Vice President & Chief Nuclear Officer PPL Susquehanna, LLC 769 Salem Boulevard Berwick, PA 18603 Tel. 570.542.3149 Fax 570.542.1504 btmckinney@pplweb.com I

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~~QI MAR 2 2 2007 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop OP 1-17 Washington, DC 20555 SUSQUEHANNA STEAM ELECTRIC STATION PROPOSED LICENSE AMENDMENT NO. 285 FOR UNIT 1 OPERATING LICENSE NO. NPF-14 AND PROPOSED LICENSE AMENDMENT NO. 253 FOR UNIT 2 OPERATING LICENSE NO. NPF-22 CONSTANT PRESSURE POWER UPRATE -

SUPPLEMENT PLA-6172 Docket Nos. 50-387 and 50-388

Reference:

1)

PPL Letter PLA-60 76, B. T. McKinney (PPL) to USNRC, "Proposed License Amendment Numbers 285for Unit 1 Operating License No. NPF-14 and 253 for Unit 2 Operating License No. NPF-22 Constant Pressure Power Uprate, " dated October 11, 2006.

Pursuant to 10 CFR 50.90, PPL Susquehanna LLC (PPL) requested in Reference 1 approval of amendments to the Susquehanna Steam Electric Station (SSES) Unit 1 and Unit 2 Operating Licenses (OLs) and Technical Specifications (TS) to increase the maximum power level authorized from 3489 megawatts thermal (MWt) to 3952 MWt, an approximate 13% increase in thermal power. The proposed Constant Pressure Power Uprate (CPPU) represents an increase of approximately 20% above the Original Licensed Thermal Power (OLTP).

In a teleconference held February 12, 2007, the NRC staff and PPL staff discussed the two questions and PPL responses contained in the Enclosure.

There are no new regulatory commitments associated with this submittal.

PPL has reviewed the "No Significant Hazards Consideration" and the "Environmental Consideration" submitted with Reference 1 relative to this supplemental information.

We have determined that there are no changes required to either of these documents.

/40(

Document Control Desk PLA-6172 If you have any questions or require additional information, please contact Mr. Michael H. Crowthers at (610) 774-7766.

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

Executed on:

c3*cZ.07 B. T. McKinney

Enclosure:

PPL Responses to NRC Questions Copy:

NRC Region I Mr. A. J. Blamey, NRC Sr. Resident Inspector Mr. R. V. Guzman, NRC Project Manager Mr. R. R. Janati, DEP/BRP

Enclosure to PLA-6172 PPL Responses to NRC Questions

Enclosure to PLA-6172 Page 1 of 4 NRC Question 1:

Table 8-4 indicates the annual collective occupational doses for pre-EPU conditions. The staff requests the licensee to provide the estimated post-EPU annual collective occupational dose. The staff would also like to know whether the licensee plans to install additional shielding on top of the turbine(s) to cut down the potential incremental doses due to "N-16 skyshine" from implementation of the EPU project.

PPL Response:

As indicated in Table 8-4 of the EPU Supplemental Environmental Report, the annual collective occupational doses at SSES have been generally decreasing during the 2000 to 2004 period. This trend has continued in the most recent years of operation as noted for the years 2005 and 2006 in the updated EPU Supplemental Environmental Report Table 8-4 provided below. PPL staff will continue implementing ALARA initiatives; however, the effects of plant aging and operation at higher capacity factors and power levels will tend to increase the collective dose. Our goal is and will continue to be to maintain performance in the top quartile of boiling water reactors in the USA.

Currently, maintenance of annual collective doses in the range of 160-200 person-rem appears to be consistent with the goal and realistic expectations for the years after EPU implementation.

Year Updated Table 8-4 Collective Occupational Radiation Dose at SSES 2000 330 person rem 2001 290 2002 260 2003 250 2004 270 2005 182 2006 184 Each of the last two refueling outages completed at SSES (2005 and 2006) resulted in a collective dose of approximately 100 person-rem. The typical annual non-outage personnel exposure is approximately 40 person-rem per unit. This has resulted in an annual total exposure of approximately 180 person-rem in each of the last two years of operation for SSES.

In the near term future, for years 2007-2009, the annual personnel dose is projected to increase due to an unusual amount of outage and non-outage work that will be needed to support EPU implementation. Detailed dose estimates for outages in 2008 and 2009 have not yet been made. Based on the current in progress 2007 outage, the dose estimated for

Enclosure to PLA-6172 Page 2 of 4 each year during the 2007-2009 period is approximately 230 person-rem, based on an estimated 130 person-rem for scheduled outage related work and 100 person-rem for planned non-outage work.

With EPU implemented (2010 and beyond), pre-EPU drywell shutdown dose rates are projected to increase by approximately the increase in power level or roughly 14%.

Since during a typical cycle the drywell outage dose is approximately 60% of the total outage exposure (based on 2005-2006 data, 100 person-rem), the post-EPU outage exposure is expected to increase to 108 person-rem, (1.14

• 60 + 1.0

• 40).

The typical non-outage exposure (40 person-rem per unit) has the potential to increase roughly in proportion to the power level increase of 14% and potentially up to 20%

locally in the main-steam-affected plant areas due to increased N-i16 levels. Therefore, the average non-outage dose is conservatively estimated at 1.17

• 40 person-rem per unit

• 2 units = 94 person-rem.

Based on the above, the total post-EPU annual collective occupational dose is estimated to be 202 person-rem (108 + 94), as compared to the most recent years' collective dose of approximately 180 person-rem.

There is no plan to install additional shielding on the top of the turbines to cut down the skyshine N-16 doses from EPU. However, localized shielding may be provided as needed based upon the results of EPU Startup and Test radiation surveys. With EPU implementation, onsite and offsite radiation doses will comply with regulatory requirements.

NRC Ouestion 2:

For the offsite doses at EPU conditions, the staff requests the licensee to provide estimates of the post-EPU conditions, considering the potential increases in direct-radiation and gaseous and liquid effluents from the units operating at EPU conditions.

PPL Response:

The Annual Radiological Environmental Operating Report documents offsite doses based on Thermo-Luminescent Dosimeter (TLD) data., The N-16 contribution to offsite dose is included in these measurements but is not measured or reported separately.

Increases in operational dose rates of up to 20% at some onsite and offsite locations due to direct and scattered radiation from main steam and turbine equipment with EPU are expected. These increases are due to an increase in N-16 activity from neutron activation that results from the increased power level of -14%.

An additional increase of less than 6% is due to a reduction in the time for N-16 decay (-7 sec half-life) resulting from the shortened transit time through the main steam and turbine equipment.

Enclosure to PLA-6172 Page 3 of 4 The additional radiation dose due to EPU at the protected area boundary fence line is estimated based on experience with implementation of Hydrogen Water Chemistry (HWC). The highest estimated annual gamma radiation doses at the protected area boundary fence line are provided in the table below.

Year Maximum Fence Dose (mrem)'

Location 1997 3.5 x 103 0.3 miles Southwest (Sector 11S 3) 1998 4.5 x 10.'

0.3 miles Southwest (Sector 11 S3) 1999 1.2 x 10-2 0.2 miles South (Sector 9S2) 2000 2.9 x 10-2 0.2 miles South (Sector 9S2) 2001 2.7 x 10.2 0.2 miles South (Sector 9S2) 2002 3.0 x 10-2 0.2 miles South (Sector 9S2) 2003 3.1 x 10-2 0.2 miles South (Sector 9S2) 2004 3.9 x 10-2 0.2 miles South (Sector 9S2) 2005 2.8 x 10.2 0.2 miles South (Sector 9S2)

'Based upon an assumed occupancy time of one hour per quarter for a member of the public at the specified fence location.

HWC implementation caused N-16 steam activity to increase by approximately 500%.

The above data reflects the impact of HWC beginning in 1999. It is estimated for EPU operation that the comparable dose at the protected area boundary fence will be approximately 0.05 mrem (1.2

• 0.039) using the highest reported fence line dose data from the above Table.

Plant operation at EPU conditions is not expected to have any measurable effect from radiation shine on offsite doses. Data from the off-site environmental TLD stations have not shown any discernible increase in radiation exposures at offsite locations due to HWC implementation.

Operation at EPU conditions is not expected to have any significant effect on the volume or activity of the wastewater treated and released, as discussed in Section 8.2.2 of the EPU Supplemental Environmental Report. Therefore, offsite doses from radioactive liquid effluents are expected to be relatively unchanged from the previously estimated average annual (2000-2004) doses of 2.05 x 10-3 mrem (total body) and 5.31 x 10-3 mrem (organ) given in Table 8-5.

Enclosure to PLA-6172 Page 4 of 4 An approximate increase in proportion to the increase in power level (or approximately 14%) in offsite doses from radioactive gaseous effluents is expected. As a result, for normal operation at EPU conditions, the average annual doses presented in Table 8-6 of the EPU Supplemental Environmental Report are projected to increase to the following values:

Noble gas air dose at site boundary Average Gamma Air Dose (mrad) 4.78 x 10-2 Beta Air Dose (mrad) 1.98 x 10-2 lodines, tritium, and particulate dose to an offsite individual Maximum dose at site boundary for all pathways (mrem) 0.90 Collective dose to members of the public within the Riverlands/Information Center Complex Collective Dose (Person-rem) 2.41 x 10-3