ML042290194

Independent Spent Fuel Storage Installation Safety Analysis Report, Revision 19, Chapter 10, Operating Controls & Limits

ML042290194
Person / Time
Site:	Robinson, 07200003
Issue date:	08/10/2004
From:	Progress Energy Carolinas
To:	Office of Nuclear Material Safety and Safeguards, Office of Nuclear Reactor Regulation
References
-RFPFR
Download: ML042290194 (7)

Text

CHAPTER 10 OPERATING CONTROLS AND LIMITS

HBRSEP ISFSI SAR 10.0 OPERATING CONTROLS AND LIMITS The H. B. Robinson (HBR) Independent Spent Fuel Storage Installation (ISFSI) is a totally passive system which requires minimum operating controls. In the following sections, the operating controls and limits that are pertinent to the ISFSI are specified. The conditions and other items to be controlled are based on the safety assessments for normal and postulated accident conditions provided in Chapter 8 of this report.

The following operating controls and limits are specified:

10.1 Fuel Specifications 10.2 Limits for the Surface Dose Rate of the HSM While the DSC is in Storage 10.3 Limits for the Maximum Air Temperature Rise After Storage 10.4 Surveillance of the HSM Air Inlets 10.5 Surveillance of the HSM Inside Cavity 10.0-1 Amendment No. 1

HBRSEP ISFSI SAR 10.1 FUEL SPECIFICATIONS

1.1 Title

Fuel Specifications

1.2 Specifications

Type 15 x 15 PWR Fuel Burnup <

_ 35,000 MWd/MT Initial (Beginning of Life)

Enrichment _ 3.5% U-235 Post Irradiation Time _ 5 years Weight Per Distance Between Adjacent Spacers Per Assembly _ 106.56 kg Distance Between Spacers <

_ 0.65 m Any fuel not specifically filling the above requirements may still be stored in the ISFSI if all the following requirements are met:

Decay Power _ 1 kw/assembly Neutron Source 1.67 x 108 n/sec/assembly 15 Gamma Source 5.73 x 10 photons/sec/canister With spectrum bounded by that shown in Table 10.1-1 End of Life 0.8% U-235 Fissile Content 0.5% Pu-239 0.1% Pu-241

1.3 Applicability

This specification is applicable to all fuel to be stored in the ISFSI.

1.4 Objective

This specification was derived to insure that the peak fuel rod temperatures, surface doses and nuclear subcriticality are below the design values.

1.5 Action

If this specification is not met, additional analysis and/or data must be presented before the fuel can be placed in the DSC.

1.6 Surveillance The fuel selected for storage must have Requirements: the parameter values specified in 1.2 above verified prior to fuel loading. No other surveillance is required.

1.7 Basis

The fuel parameters specified in this operating control and limit were selected to bound the types of PWR fuel which were in use at the time the HBR ISFSI was installed and loaded with spent fuel.

10.1-1 Revision No. 12

HBRSEP ISFSI SAR TABLE 10.1-1 ACCEPTABLE RADIOLOGICAL CRITERIA FOR STORAGE OF MATERIAL IN THE HBR ISFSI CRITERION VALUE___

16 GAMMA SOURCE PER CANISTER (total) 1.48 x 10 Mev/sec Fractional Breakdown1 Above 1.3 Mev 0.004 Between 1.3 Mev and 0.8 Mev 0.114 Between 0.8 Mev and 0.4 Mev 0.808 Below 0.4 Mev 0.074 NEUTRON SOURCE PER CANISTER (total)2 1.17 x 109 n/sec Fractional Breakdown Above 5 Mev 5.40 x 107 n/sec = 5.41%

Between 2.5 and 5 Mev 2.43 x 108 n/sec = 24.32%

Between 1 and 2.5 Mev 4.56 x 108 n/sec = 45.67%

Below 1 Mev 2.45 x 108 n/sec = 24.53%

1 Fractional breakdown is based on isotopic composition and resulting gamma spectrum calculated by ORIGEN2 analysis.

2 Spectrum from U-235 fission, total number of neutrons per second from ORIGEN2 analysis.

10.1-2 Revision No. 19

HBRSEP ISFSI SAR 10.2 LIMITS FOR THE SURFACE DOSE RATE OF THE HSM WHILE THE DSC IS IN STORAGE 2.l

Title:

Surface Dose Rates on the HSM While the DSC is in Storage

2.2 Specification

Surface dose rates at the following locations

1) Outside of HSM door on centerline of DSC 200 mrem/hr

2) Center of air inlets 200 mrem/hr

3) Center of air outlets 200 mrem/hr Average Dose rates for the following surfaces

1) Roof 50 mrem/hr

2) Front/Back 50 mrem/hr

3) Side 50 mrem/hr Dose rates one meter from the center of the following surfaces of a unit of modules

1) Front/Back 20 mrem/hr

2) Side 20 mrem/hr

2.3 Applicability

This specification is applicable to the ISFSI.

2.4 Objective

The objective of this specification is to maintain as-low-as-reasonably-achievable dose rates on the modules.

2.5 Action

If the dose rates are exceeded, temporary shielding must be placed so as to reduce the dose rates to the specified levels. When temporary shielding is used, the outlet air temperature must be measured after the shielding is installed to verify that the air flow has not been restricted.

2.6 Surveillance

The HSM shall be monitored to verify that this specification has been met immediately after the DSC is placed in storage and the HSM front and rear accesses are closed.

2.7 Basis

The dose rates stated in this specification were selected to maintain as-low-as-reasonably-achievable exposures to personnel performing air duct clearing on the HSM. These dose rates are within industry accepted standards for contact handling, operation and maintenance of radioactive material. Maintenance personnel will be required to remove any potential air blockage. At 200 mrem/hr the dose for a one hour job of unblocking the air inlets (or outlets) would be less than 200 mrem (whole body) and hence would be only 4% of the total yearly burden. Furthermore, analysis provided in Chapter 7 of the HBR ISFSI SAR shows that the expected dose rates around the HSM surface will be well below the specifications listed above.

10.2-1 Revision No. 19

HBRSEP ISFSI SAR 10.3 LIMITS FOR THE MAXIMUM AIR TEMPERATURE RISE AFTER STORAGE

3.1 Title

Maximum Air Temperature Rise from HSM Inlet to Outlet

3.2 Specification

Maximum air temperature rise l00oF (55.6oC)

3.3 Applicability

This specification is applicable to the ISFSI.

3.4 Objective

To limit the maximum air temperature around the DSC.

3.5 Action

If the temperature rise is greater than l00oF (55.6oC), the air inlets and exits should be checked for blockage. If the blockage is cleared and the temperature still exceeds this limit, the DSC must be removed from the module or additional information and analysis shall be provided that will prove the existing condition does not represent an unsafe condition.

3.6 Surveillance

The temperature rise shall be checked at the time the DSC is stored in the HSM, again 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> later, and again after 7 days.

3.7 Basis

The l00oF (55.6oC) temperature rise was selected to limit the hottest rod in the DSC to below 716oF (380oC). If this temperature rise is maintained, then the hottest rod will be below the 716oF (380oC) limit even on the hottest day conditions of 125oF (5l.7oC). The expected temperature rise is less than 100EF (i.e., 82EF (45.5EC) per NUHOMS Topical Report (Reference 8.1), Section 8.1.3) and hence, the current design provides adequate margin for this specification. If the temperature rise is within the specifications, then the HSM and DSC are performing as designed and no further temperature measurements are required during normal surveillance.

10.3-1 Revision No.19

HBRSEP ISFSI SAR 10.4 SURVEILLANCE OF THE HSM AIR INLETS AND OUTLETS

4.1 Title

Surveillance of the HSM Air Inlets and Outlets

4.2 Specifications

Normal visual inspection frequency: Daily Accident visual inspection frequency: Within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after an accident

4.3 Applicability

This specification is applicable to the ISFSI.

4.4 Objective

To assure that no HSM air inlets or outlets are plugged for more than 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> and to assure that complete blockage of all inlets and exits due to an accident will be removed in less than 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />.

4.5 Action

If the air inlets or outlets are plugged, they should be cleared. If the screen is damaged, it should be replaced.

4.6 Surveillance

The HSM shall be inspected to verify that the air inlets are free from obstructions.

4.7 Basis

Analysis in Chapter 8 of the HBR ISFSI SAR showed that no temperature limits are exceeded if a module is completely plugged for 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. Furthermore, analysis showed that blockage of the air inlet alone did not result in unacceptable temperatures.

Therefore, for normal operations, an inspection of the inlets once per day will assure that any local obstructions can be removed. Likewise, after an accident (such as those described in Chapter 8) the HSMs should be examined within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to assure that if a module is completely buried, flow can be restored within another 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

10.4-1 Revision No. 19