ML20101M160

Application for Amend to License NPF-3,App A,Re Surveillance Requirements for Charcoal Filter Lab Testing to Revise Testing Methodology Used to Determine Operability of Charcoal Filters in ESF Air Handling Units

ML20101M160
Person / Time
Site:	Davis Besse
Issue date:	03/29/1996
From:	Stetz J CENTERIOR ENERGY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20101M131	List: ML20101M128 ML20101M160 ML20101M192
References
2369, NUDOCS 9604050168
Download: ML20101M160 (9)

Text

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.. Docket Number 50-346 License Number NPF-3

. ' Serial Number 2369 Enclosure Page 1 APPLICATI M FOR AMRN M W T

'M)  !

FACILITY OPERATING LICENSE NUMBER NPF-3 l DAVIS-BESSE NUCLEAR POWER STATI N UNIT NUMBER 1 I

Attached is the requested change to the Davis-Besse Nuclear Power Station, Unit Number 1, Facility Operating License Number NPF-3. Also )

l included is the Safety Assessment and Significant Hazards Consideration and the Environmental Assessment.

The proposed changes (submitted under cover letter Serial Number 2369) concern.

I Appendix A, Technical Specifications 3/4.6.4.4 - Hydrogen Purge System,  !

3/4.6.5.1 - Shield Building Emergency Ventilation System, and (

TS 3/4.7.6.1 - Control Room Emergency Ventilation System. I 1

I By:

J. P. Stetz" Vic( President - Nuclear Sworn to and subscribed before me this 29th day of March,1996.

ML . %-x rt - M 0 h9 N '

NotaryPublic,flateofOhio '

My Commission expires 9/3/97.

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f 9604050168 960329 PDR ADOCK 05000346 P PDR l

l l ,- . Docket Number 50-366

• License Number NPF-3

• 5erial Number 2369 l Enclosure Page 2 l

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The following information is provided to support issuance of the requested changes to the Davis-Besse Nuclear Power Station (DBNPS), Unit Number 1, Facility Operating License Number NPF-3, Appendix A, Technical Specifications. The changes involve Technical Specifications 3/4.6.4.4 -

Hydrogen Purge System, 3/4.6.5.1 - Shield Building Emergency Ventilation System, and TS 3/4.7.6.-l - Control Room Emergency Ventilation System.

A. Time Required to Implement: This change is to be implemented upon NRC i

issuance of the License Amendment.

B. Reason for Change (License Amendment Request Number 96-0004):

1 The proposed changes involve the aforementioned Technical Specifications (TS) regarding the Surveillance Requirements for charcoal filter laboratory testing to revise the testing methodology used to determine operability of the charcoal filters in the engineered safety features (ESF) air handling units. Currently, the DBNPS is required to test charcoal in the ESF air handling units per Regulatory Guide 1.52, Revision 2, " Design, Testing, and Maintenance Criteria For Post Accident Engineered-Safety-Feature Atmosphere l Cleanup System Air Filtration and Adsorption Units of i Light-Water-Cooled Nuclear Power Plants," dated March 1978. However, I the DBNPS has been utilizing an alternative method of testing which, l although it provides accurate assurance that these air handling units l will perform their design function, it'does not literally comply with l a strict reading of the TS. The proposed changes incorporate the l current testing methodology.

l C. Safety Assessment and Significant Hazards Conside ation: See Attachment 1.

D. Environmental Assessment: See Attachment 2.

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i Docket Number 50-346  ;

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• License Number NPF-3 j Serial Number 2369 Attachment 1 SAFETY ASSESalarr AND SIGNIFICANT l HAZARDS CMSIDERATION i i

FOR l

LICENSE AMinKEnerr REQUEST NO. 96-0004 i (15 pages follow) l l

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LAR 96-0004 Page 1 l

l SAFETY ASSESSMENT AND SIGNIFICANT HAZARDS CONSIDERATION 1

I FOR LICENSE AMENDMENT REQUEST No. 96-0004 l

TITLE:

Revision of Technical Specifications (TS) 3/4.6.4.4, Hydrogen Purge System, 3/4.6.5.1, Shield Building Emergency Ventilation System, and 3/4.7.6.1, l Control Room Emergency Ventilation System.

l DESCRIPTION:

The purpose of the proposed change is to modify the Davis-Besse Nuclear Power Station (DBNPS), Unit 1 Operating License NPF-3, Appendix A, Technical Specifications (TS). The proposed changes would revise the charcoal filter laboratory testing criteria specified in Surveillance l

Requirements (SR) 4.6.4.4.b.2, 4.6.4.4.c, 4.6.5.1.b.2, 4.6.5.1.c, t

4.7.6.1.c.2, and 4.7.6.1.d, to reflect the current testing methodology.

Each of the above-referenced Surveillance Requirements specify that the laboratory testing criteria follow Regulatory Position C.6.a of Regulatory Guide 1.52, " Design, Testing, and Maintenance Criteria for Post Accident l

Engineered-Safety-Feature Atmosphere Cleanup System Air Filtration and Adsorption Units of Light-Water-Cooled Nuclear Power Plants," Revision 2, March 1978, for a methyliodide penetration of less than 1%. These requirements are as follows:

Regulatory Position C.6.a of Regulatory Guide (RG) 1.52, Revision 2, includes requirements that new activated carbon meet the physical property specifications given in Table 5-1 of ANSI N509-1976, " Nuclear Power Plant Air Cleaning Units and i

Components," and that representative samples of used activated  !

carbon pass the laboratory tests given in RG 1.52, Table 2.

The RG 1.52, Table 2 laboratory testing requirements applicable i to the above-referenced SRs refer to Test 5.b of Table 5-1 of ANSI N509-1976 at a relative humidity of 70% for a methyliodide penetration of less than 1%.

Test 5.b of Table 5-1 of ANSI N509-1976 specifies that an acceptable test method is RDT M16-1T, " Gas-Phase Adsorbents for Trapping Radioactive Iodine and Iodine Compounds," except 80oC j and 95% relative humidity air is specified for the test, and the j pre-loading and post-loading sweep medium is 25oC. )

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l LAR 96-0004 Page 2 l

Laboratory testing is presently performed in accordance with ASTM D 3803-1979, " Standard Test Methods for Radioiodine Testing of Nuclear-Grade Gas- I Phase Adsorbents," with the following conditions:

1) Equilibrate for 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> at 30oC and 70% relative humidity

2) Challenge for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> at 30oC and 70% relative humidity

3) Elution for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> at 30oC and 70% relative humidity j l Although this testing methodology is comparable and conservative to '

RG 1.52, it does not meet the literal requirements of the applicable SRs.

Therefore, the proposed changes would add a footnote describing the testing methodology presently in use. These proposed changes are shown on the attached marked-up TS pages.

SYSTEMS, COMPONENTS, AND ACTIVITIES AFFECTED:

The systems affected are the Containment Hydrogen Purge System, the Shield Building Emergency Ventilation System, and the Control Room Emergency Ventilation Systems. The components affected are the charcoal (carbon) filter beds in each of these systems. The activities affected are the periodic surveillance tests performed on representative carbon samples taken from the charcoal filter beds.

l NNCTIONS OF THE AFFECTED SYSTEMS, COMPONENTS, AND ACTIVITIES:

The Shield Building Emergency Ventilation System (EVS) is designed to l provide a negative pressure within the annular space between the shield I building and the containment vessel and in the penetration rooms following l a Loss of Coolant Accident (LOCA), and to reduce the fission product l leakage to the environment by filtration prior to release through the

! station vent. Operation of this system reduces the site boundary doses to j within the limits of 10CFR100 following a LOCA. The EVS consists of two '

redundant fan-filter trains. The filter bank consists of a prefilter, a l HEPA filter and two charcoal adsorber units. The DBNPS Updated Safety l Analysis Report (USAR) Section 6.2.3, " Containment Vessel Air Purification and Clean-up Systems," discusses the design bases for the EVS. The two redundant fan-filter trains would remove airborne particles, methyliodide i

and elemental iodine contaminants resulting from a LOCA. Per the USAR, the filters have a total efficiency of not less than 95%. The system flow rate is designed for 8000 scfm. The USAR Chapter 15 analyses for LOCA and for the fuel handling accident assume an EVS charcoal efficiency of 95% for releases to the station vent.

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LAR 96-0004 Page 3 The Hydrogen Purge System (HPS) is designed to reduce hydrogen concentrations in containment, following a LOCA, by exhausting hydrogen from the containment vessel, through filters, to the station vent.

Operation of this system in conjunction with the Containment Hydrogen Dilution (CHD) System maintains hydrogen concentration in the containment vessel within allowable limits following a LOCA and ensures containment integrity. The driving head for this process is provided by the CHD l System. The HPS filter package consists of two HEPA filters and one l charcoal adsorber. The USAR Section 6.2.5, " Combustible Gas Control in

! Containment Vessel," discusses the design bases for the HPS. The scenario l of hydrogen purging for containment hydrogen control is evaluated for two l cases: (1) filter removal efficiency of 95% for all forms of iodine; and (2) no iodine removal by the filters.

The Control Room Emergency Ventilation System (CREVS) is designed to provide filtered and conditioned air to the control room in the event of high radioactivity. This ensures control room equipment and habitability for control room personnel remain unaffected during and following all credible accident conditions. Operability of CREVS, in conjunction with other control room design provisions, is based on limiting control room l personnel exposure consistent with the requirements of General Design Criterion 19, " Control Room," of Appendix A of 10CFR50. Following a LOCA, the normal control room ventilation system is automatically shutdown and isolated, and the CREVS is manually activated to recirculate control room air through one of two redundant trains. Each of the two 100 percent capacity trains contains a set of filter banks which consists of a prefilter, a HEPA filter, and a charcoal adsorber which are rated for 3300 scfm in the isolation mode. The USAR Section 9.4.1 " Control Room,"

discusses the design bases for the CREVS. The total efficiency of the filters is not less than 95%. The USAR Chapter 15 analyses for a LOCA assumes a CREVS charcoal adsorber unit efficiency of 95% for elemental, particulate and organic material.

EFFECTS ON SAFETY:

The purpose of charcoal adsorber testing is to confirm that iodine removal efficiencies used in the accident analysis are appropriate. There are several methods of testing which can adequately demonstrate the validity of assigned iodine removal efficiencies.

The difference in testing between RG 1.52 and the current DBNPS test methodology is in the pre-load and post-load sweep temperatures, and the test temperatures. Regulatory Guide 1.52 requires pre-load and post-load sweep tests be conducted at 25oC and testing be conducted at 80oC. Current DBNPS test practices perform all testing at 300C.

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l LAR 96-0004 Page 4 The requirements of ASTM D 3803-1979 Method A are:

1. Equilibration for new carbon et 30oC and 95% relative humidity for 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br />. Equilibration for used carbon at 30oc.

2. Feed for new and used carbons at 300C and 95% relative humidity for 120 minutes.

l 3. Elution for new and used carbons at 300C and 95% relative humidity 1

for 240 minutes.

This differs from the current DBNPS test methodology in that equilibration for used carbon is conducted with humidity for 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> and that elution is conducted for 120 minutes. Also, all testing is conducted at 70% relative l

humidity. Other testing requirements meet the requirements of ASTM D3803-1979. The acceptance criteria of 1% penetration is also unchanged.

The quantity of water retained by charcoal is dependent on temperature.

Generally, the higher the temperature, the less water retained. The water retained by the carbon decreases the efficiency of the carbon to adsorb contaminants. Therefore, the lower temperature test medium of the proposed TS changes will yield more conservative results than the present TS.

The current DBNPS test methodology is in accordance with ASTM D 3803-1979 l with the cited exceptions. The change to 30oC provides more conservative l testing than the RG 1.52 required 80oC and there is little difference in l the adsorption behavior of carbon between 25oC and 30oC. The 70% relative '

humidity and two hour elution are in accordance with RG 1.52. Therefore, the lower temperature test medium of the proposed TS change will yield more l conservative results. I i 4 Therefore, there is no adverse impact on safety. l I

SIGNIFICANT HAZARDS CONSIDERATION:

l The Nuclear Regulatory Commission has provided standards in 10CFR50.92(c) l for determining whether a significant hazard exists due to a proposed

! amendment to an Operating License for a facility. A proposed amendment l involves no significant hazards consideration if operation of the facility l in accordance with the proposed changes would: (1) Not involve a signifi-I cant increase in the probability or consequences of an accident previously evaluated; (2) Not create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) Not involve a significant reduction in a margin of safety. Toledo Edison has reviewed the proposed change and determined that a significant hazards consideration i

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LAR 96-0004 i Page 5 '

does not exist because operation of the Davis-Besse Nuclear Power Station, i Unit No. 1, in accordance with these changes would: I la. Not involve a significant increase in the probability of an accident previously evaluated because no accident initiators, conditions, or assumptions are significantly affected by the proposed changes to the carbon sample laboratory test methodology. The proposed test methodology is considered to be more conservative than

' the testing methodology mandated by the current Technical Specifications. The proposed changes do not result in the operation of equipment important to safety outside their acceptable operating range.

lb. Not involve a significant increase in the consequences of an l accident previously evaluated because the proposed change does not I

change the source term, containment isolation, or allowable releases. 1

2. Not create the possibility of a new or different kind of accident from any accident previously evaluated because no new accident initiators or assumptions are introduced by the proposed changes. The proposed l changes do not result in installed equipment being operated in a l manner outside its design operating range. No new or different l

equipment failure modes or mechanisms are introduced by the proposed changes.

3. Not involve a significant reduction in a margin of safety because the proposed changes do not have a significant effect on the initial conditions contributing to accident severity or consequences, l

consequently there are no significant reductions in a margin of safety.

CONCLUSION:

1 On the basis of the above, Toledo Edison has determined that the License Amendment Request does not involve a significant hazards consideration. As l this License Amendment Request concerns a proposed change to the Technical Specifications that must be reviewed by the Nuclear Regulatory Commission, this License Amendment Request does not constitute an unreviewed safety question.

l ATTACHMENT:

Attached are the proposed marked up changes to the operating License.

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REFERENCES:

1. Davis-Besse Nuclear Power Station Operating License NPF-3, Appendix A, Technical Specifications through Amendment 208.

2. Davis-Besse Nuclear Power Station Updated Safety Analysis Report through Revision 19.

3. Regulatory Guide 1.52, Revision 2, March 1978, " Design, Testing, and Maintenance Criteria for Post Accident Engineered-Safety-Feature Atmosphere Cleanup System Air Filtration and Adsorption Units of Light-Water-Cooled Nuclear Power Plants."

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4. ANSI N509-1976, " Nuclear Power Plant Air Cleaning Units and Components."

l 5. U.S. Department of Energy RDT-M16-IT, " Gas-Phase Adsorbents for I

Trapping Radioactive Iodine and Iodine Compounds."

6. ASTM D 3803-1979, " Standard Test Methods for Radioiodine Testing of Nuclear-Grade Gas-Phase Adsorbents."