ML20151R940
| ML20151R940 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 08/01/1988 |
| From: | Shelton D TOLEDO EDISON CO. |
| To: | |
| Shared Package | |
| ML20151R816 | List: |
| References | |
| NUDOCS 8808120353 | |
| Download: ML20151R940 (17) | |
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'. 'Dockst No. 50-346-Lictnsa No. NPF-3 Serial No. 1494
- -Enclosure Page 1 APPLICATION FOR AMENDHENT TO FACILITY OPERATING LICENSE NO. NPF-3 FOR DAVIS-BESSE NUCLEAR POVER STATTON UNIT NO. 1 Attached are requested changes to the Davis-Besse Nuclear Power Station, Unit No. 1 Facility Operating License N3. NPF-3. Also' included are the Safety Evaluation and Significant Hazards Consideration.
Thq proposed changes (submitted under cover letter Serial No. 1494) concernt Section 3/4.6.4.4, Contsinment Systems, Hydrogen Purge Systems, Specification 4.6.4.4b.1;b.2;c;d.1;d.2;e;f; Section 3/4.6.5.1, Containment Systems, Emergency Ventilation System, Specification 4.6.5.1b.1;b.2;b.3;b.4;c;d.1;d.2;d.3;d.4;e,f; Section 3/4.7.6.1, Plant Systems, Control Room Emergency Ventilation System, Specification 4.7.6.la;c.1;c.2;c.3;c.4;d,e;1;e.2;e.3;f;g. i By D. C.-Shelton, Vice. President, Nuclear Sworn and subscribed before me this 1st day of Aagnst, 1988.
Quazl tary Public, State of Ohio sd -
JUDITH HIRSCH Notary Pubec State Of ONo My Commission Expires June 30,1992 8808120353 880801 PDR ADOCK0500g6 P
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Dacket No. 50-346 Licensa No. NPF-3 Serial No.1 1494 Enclosure l Page 2 l 1
The following information is provided to support. issuance of the requested :
. changes (Attachment 3) to the Davis-Besse Nuclear Power Station, Unit No. 1 !
Operating License No. NPF-3, Appen' dix A, Technical Specification Sections f
-4.6.4.4, 4.6.5.1 and 4.7.6.1. i A. Time required to Implement: -This change vill be implemented by the Licensee within 45 days following NRC issuance of the License Amendment.
B. Reason for Change: (FCR No. 86-0402): This change to the Technical'-
Specifications Surveillance Requirements vill clarify the testing requirements and update'the references for High Efficiency Particulate Air (HEPA) filters and charcoal adsorber units in Engineered Safety Feature (ESP) cleanup systems.
C. Safety Evaluation: See attached Safety Evaluation (Attachment No.'l).
D. Significant Hazards Consideration: See attached Significant Hazards Consideration (Attachment No. 2).
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.Dockst No. 50-346 Licznse No. NPF-3 Serial No. 1494 Attachment i l Page 1 i SAFETY EVALUATION DESCRIPTION The purpose of this Safety Evaluation is to review the proposed revisions to the Davis-Besse Nuclear Power Station (DBNPS), Unit'Ne. 1, Technical Specifications (TS) in accordance with the requirements of 10CFR50.59 to ensure that an unreviewed safety question does not caist. The changes to the DBNPS TS Surveillance Requirements (SRs) are proposed to clarify the testing requirements, and update the references, for High Efficiency Particulate Air (HEPA) filters and charcoal adsorber units in Enginerred Safety Feature (ESP) atmosphere cleanup systems.
The following ESF systems and associated TS SRs are affected by this revision:
DBNPS ESF SYSTEM DBNPS TS Hydrogen Purge System (HPS). SR 4.6.4.4 Emergency Ventilation System (EVS) SR 4.6.5.1 Control Room Emergency Ventilation System (CREVS) SR 4.7.6.1 These TS SRs do not clearly reflect the required relationship between the guidance provided in Regulatory Guide 1.52, Revision 2, (Ref. 4), and ANSI N510-1975 (Ref. 5). the testing requirements of the HEPA filters and charcoal adsorber units.
The existing TS SRs state that,
...the system satisfies the in-place testing acceptance criteria and uses the test procedures of Regulatory Positions C.S.a, C.S.c, and C.5.d of Regulatory Guide 1.52, Revision 1, July 1976..."
Regulatory Guide 1.52 requires in-place testing of HEPA filters and charcoal adsorber units. The in-place Dioctyl Phthalate (DOP) penetration and bypass leakage testing acceptance criteria for the HEPA filters is 0.05 percent at rated flov. Based on this criteria an ESF air filtration system is considered to varrant a 99 percent removal efficiency for particulates in accident dose evaluations. The in-place gaseous halogenated hydrogen refrigerant bypass leakage testing acceptance criteria specified by Regulatory Guide 1.52 for charcoal adsorber units is also 0.05 percent.
A charcoal adsorber unit efficiency is not associated with this in-place bypass testing criteria. The existing TS SR does, however, state:
...that a laboratory analysis of a representative carbon sample obtained in accordance with Regulatory Position C.6 of Regulatory Guide 1.52, Revision 1, July 1976, meets the laboratory testing criteria of Regulatory Position C.6.a of Regulatory Guide 1.52, Revision 1, July 1976".
. Dockat No. 50-346 Lictnse No. NPF-3 Serial No. 1494 Attachment 1 Page 2 This requirement assigns a carbon decontamination efficiency based on the carbon bed depth and laboratory testing results.
The existing TS SR requires that in-place DOP testing be in accordance with ANSI N510-1975. This revision of the ANSI is referenced in the existing DBNPS surveillance test procedures for the HPS, EVS, and CREVS.
NRC Generic Letter No. 83-13 (Ref. 3) was issued to clarify'the requirements of, and the relationship between, Regulatory Guide 1.52, kevision 2, ANSI N510-1975, and the NRC staff's assumptions used in its safety evaluations for ESF atmosphere cleanup systems. This document contains revised testing requirements for HEPA filters and charcoal adsorber units to be used in licensee submittals of proposed TS revisions. The revised 13 SRs, as stated in Reference 3, allow in-place, bypass leakage and penetration testing acceptance criteria of 1 percent when a HEPA fi.lter or charcoal adsorber efficiency of 95 percent or less is assumed in the NRC staff's safety evaluation. NRC Generic Letter 83-13 further states, "Use the value assumed for the charcoal adsorber efficiency if the value for the HEPA filter is different from the charcoal adsorber efficiency in the NRC staff's safety evaluation."
The DBNPS Final Safety Analysis Report _(FSAR) evaluation of the ESF atmosphere cleanup systems assumes a charcoal adsorber efficiency of 95 percent. HEPA filter efficiency is not specifically addressed in the evaluation. The DBNPS FSAR vas reviewed by the Nuclear Regulatory Commission (NRC) and the staff issued a Safety Evaluation Report (Ref. 6) documenting this review. The NRC concurred with the evaluation for the ESF atmosphere cleanup systems contained in the FSAR including the 95 percent cfficiency assumed for the charcoal adsorber. DBNPS surveillance testing proceduras for ESF bypass testing uses an acceptance criteria of less than 1 percent for penetration and bypass leakage.
The changes to the existing TS SRs are proposed to incorporate the following:
- 1. The generic wording in the SR enclosed in NRC Generic Letter 83 as applicable to the DBNPS ESF atmospheric cleanup systems and FSAR evaluation assumptions.
- 2. The updating of ANSI N510-1975, referenced in the existing TS SRs, to the current issue, ANSI N510-1980. The ANSI N510-1980 changes have been reviewed for impact on the TS SRs. This issue provides clarification of the testing requirements for ESP atmosphere cleanup ;
1 systems.
- 3. Editorial changes to provide consistency and clarity for the DBNPS ESP atmospheric cleanup system TS SRs.
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, Dockst N3.-50-346 Lictnst No. NPF-3 Serial No. 1494 Attachment 1 Page 3 SYSTEMS AND COMPONENTS AFFECTED Hydrogen Purge System Emergency Ventilation System Control Room Emergency Ventilation System SAFETY FUNCTIONS AFFECTED The EVS is designed to maintain a negative pressure within the negative pressure boundary areas following a Loss of Coolant Accident (LOCA), and to reduce the fission product content of the system exhaust prior to release through the station vent. Operation of this system reduces the site boundary doses to within the limits of 10CFR100 following a LOCA. The negative pressure boundary areas include the containment annulus, the mechanical penetration rooms, the Makeup Pump room, the Emergency Core Cooling System (ECCS) rooms and the Decay Heat Removal cooler room. EVS consists of two redundant fan-filter trains. The filter bank consists of a prefilter, a HEPA filter and two charcoal adsorber units. USAR Section 6.2.3.1 discusses the design bases for the EVS. The two redundant EVS subsystems are provided with f prefilters, HEPA filters and charcoal adsorber units to remove airborne l particles, methyl iodine and elemental iodine contaminants resulting from a LOCA. Per the USAR, the filters have a total efficiency not less than 95 percent. 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 percent for releases to the station vent.
The HPS is designed to reduce hydrogen concentrations in containment, ;
( following a LOCA, by exhausting hydrogen from the containment vessel, through !
l filters, to the station vent. Operation of this system in conjunction'vith l the Containment Hydrogen Dilution (CHD) system maintains hydrogen concentration in the containment vessel within allovable limits following a l
LOCA and ensures containment integrity. The driving head for this process is provided by the CHD System. The filter package consists of a demister, heater, {
and filt.er unit. The HPS filter package consists of two HEPA filters and one i charcoal adsorber. USAR.Section 6.2.5.1 discusses the design bases for the HPS. The scenario of hydrogen purging for containment hydrogen control is evaluated for two cases; (1) filter removal efficiency of 95 percent for all forms of iodine, and (2) no iodine removal by the filters. The flow rate during purging for either case is assumed to be the HPS rated flow rate of 100 scfm.
The CREVS is designed to provide filtered and conditioned air to the control room in the event of high radioactivity or toxic airborne contaminants. This ensares that control room conditions do not affect control room equipment and habitability for control room personnel during and following all credible accident conditions. Operability of CREVS, in conjunction with other control !
I room design provisions, is based on limiting control room personnel exposure
'. Dockat No. 50-346 Licensa No. NPP-3 Serial No. 1494 Attachment 1 Page 4 consistent with the requirements of General Design Criteria 19 of Appendix A of 10CFR50. Following a LOCA or toxic leak, 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. USAR Section 9.4.1.1 discusses the design bases for the CREVS. The total efficiency of the filters is not less than 95 percent. The USAR Chapter 15 analyses for a LOCA assumes a CREVS charcoal adsorber unit efficiency of 95 percent for elemental, particulate and organic material.
EFFECTS ON SAFETY The ESF atmosphere cleanup systems are periodically tested to assure operability per the TS requirements. HEPA filter penetration testing is required to provide an indication of the installed filter efficiency iginally established by factory testing and reveal the presence of leaks in the system. Charcoal adsorber penetration testing indicates leak-tightness of the installed assembly. Efficiency of the in-place charcoal adsorber is inferred by laboratory analysis of a representative carbon sample.
NRC Generic Letter 83-13 establishes an in-place penetration and bypass leakage test acceptance criteria of less than 1 percent when a charcoal adsorber efficiency of 95 percent is assumed in the NRC staff's~Jafety evaluation. It also references sections of Regulatory Guide 1.52, Revision 2, March 1978 for test procedure guidance (C.5.a, C.5.c, C.5.d), carbon sampling for laboratory analysis (C.6.b), and laboratory testing criteria (C.6.a).
ANSI N510-1975 is referenced for in-place leak testing of HEPA filters with DOP aerosol and charcoal adsorbers vith a halogenated hydrocarbon refrigerant test gas.
The proposed revisions to the DBNPS ESP atmosphere cleanup system TSs for HPS (SR 4.6.4.4), EVS (SR 4.6.5.1) and CREVS (SR 4.7.6.1) are evaluated below for impact on the USAR analyzed events.
- 1. Revised TS SR vording in accordance with NRC Generic Letter 83-13 l TS Section Affected: SR 4.6.4.4b.1, SR 4.6.5.lb.2, SR 4.7.6.1c.2 The in-place penetration and bypass leakage testing acceptance criteria of less than 1 percent is in accordance with the charcoal adsorber efficiency of 95 percent assumed in the USAR evaluation.
Performance of testing using the test procedure guidance in Regulatory Position C.5.a, C.5.c and C.S.d of Regulatory Guide 1.52, Revision 2, March 1978 neither alters the surveillance test requirements, nor affects the USAR evaluation. Additional guidance and clarification of in-place testing criteria is provided by reference to these regulatory positions.
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Dockst No. 50-346 i
Lictnsa No. NPF-3 l Serial No. 1494
! Attachment 1 Page 5 TS Section Affected: SR 4.6.4.4b.2, SR 4.6.4.4c, SR 4.6.5.1b.3, SR 4.6.5.lc, SR 4.7.'6.1c.3, SR 4.7.6.1d A carbon sample obtained in accordance with-Regulatory Position C.6.b of Regulatory Guide 1.52, Revision 2, March 1978, does not alter the surveillance test requirements or affect the USAR evaluation. The change clarifies the_ requirements for replacement of the activated carbon adsorber section with new, unused activated carbon.
The laboratory testing criteria of Regulatory Position C.6.a of Regulatory Guide 1.52, Revision 2, March 1978, for a methyl iodine penetration of less than 1 percent does not alter the surveillance test requirements or affect the USAR evaluation. The change specifically states-the penetration acceptance criteria and also clarifies the requirements for new activated carbon.
TS Section Affected: SR 4.6.4.4e, SR 4.6.5.le, SR 4.7.6.lf Verification that after each complete or partial replacement of a HEPA filter bank, the bank satisfies the in-place penetration testing and bypass leakage acceptance criteria of less than 1 percent for a DOP test aerosol, is in accordance with the charcoal adsorber efficiency of 95 percent assumed in the USAR evaluation.
TS Section Affected: SR 4.6.4.4f, SR 4.6.5.lf, SR 4.7,o.lg Verification that, after each complete or partial replacement of a charcoal adsorber unit bank, the charcoal bank satisfies the in-place penetration and bypass leakage testing ar.ceptance criteria of less than 1 percent for a halogenated hydrocarbon refrigerant test gas, is in accordance with the charcoal adtarber efficiency of 95 percent assumed in the USAR evaluation.
- 2. Revised TS SR reference of ANSI N510-1975 to the current issue, ANSI N510-1980 TS Section Affected: SR 4.6.4.4d.2 Testing system heaters in accordance with ANSI N510-1980 the current approved revision, does not alter the requirements of the 1975 revision and provides consistency with the reference of the 1980 revision in other sections of the proposed TS revision. This change does not affect the USAR evaluation.
TS Section Affected: SR 4.6.4.4e, SR 4.6.5.le, SR 4.7.6.lf DOP testing acceptance criteria in accordance with ANSI N510-1980, the currently applicable revision, provides clarification of the requirements of the 1975 revision. This change does not affect the USAR evaluation.
. Dockat No. 50-346 Licensa No. NPF-3 Serial No. 1494 Attachment 1 Page 6 TS Sec; ion Affected: SR 4.6.4.4f, SR 4.6.5.lf, SR 4.7.6.lg Halogenated hydrocarbon refrigerant gas testing in accordance with ANSI N510-1980,. the currently applicable revision, provides clarification of the requirements of the 1975 revision. This change does not affect the USAR evaluation.
TS Section Affected: SR 4.6.5.1b.4, SR 4.7.6.lc.4 Verification of system flowrate in accordance with ANSI.N510-1980, the currently applicable revision, provides additional procedure information and clarification of the test requirements stated in the 1975 revision.' The system flovrate is as stated in the USAR analysis.
- 3. Revised TS SRs'to incorporate editorial clarifications TS Section Affected: SR 4.6.4.4b.2, SR 4.6.5.lb.3,'SR 4.6.5.1c, SR 4.7.6.1c.3 The deletion of the specific footnote requirements is in accordance-with Revision 2, dated March 1978, of Regulatory Guide 1.52 for testing of new activated carbon. The specific testing requirements for activated carbon have been deleted from this footnote and incorporated by reference into the appropriate TS sections. This change does not alter the surveillance test requirements.
TS Section Affected: SR 4.6.4.4d.1, SR 4.6.5.1d, SR 4.7.6.la, SR 4.7.6.le These are miscellaneous. editorial changes to the SRs which do not affect the USAR evaluation.
TS Section Affected: SR 4.6.5.lb.1, SR 4.7.6.lc.1 l
Deletion of this section is editorial in nature'. The requirements of these sections are adequately stated in the proposed revisions to TS sections SR 4.6.5.lb.2 and SR 4.7.6.1c.2, respectively. This change does not affect the USAR evaluation.
UNREVIEVED SAFETY OUESTION EVALUATION l
Revising the TS, as proposed, to clarify and update the SR for the ESP 1 atmosphere cleanup systems vill not increase the probability of an accident previously evaluated in the USAR. The ESF atmosphere cleanup systems are standby systems designed to mitigate the consequences of certain design basis accidents. The systems are not normally in operation, except for periodic testing. Consequently, HPS, EVS, and CREVS do not contribute to the initiation of any USAR accident. (10CFR50.59(a)(2)(i))
Docket No. 50-346 Lietnsa No. NPF-3 Serial No. 1494 Attachment 1 Page 7 Revising the TS, as proposed, to clarify and update the SR for the ESF atmosphere cleanup systems vill not increase the consequences of an accident previously evaluated in the USAR. The ESF atmosphere cleanup systems are designed to mitigate the consequences of design basis accidents. The SR changes do not affect the system operability or component performance assumed in the USAR analysis. (10CFR50.59(a)(2)(i))
Revising the TS, as proposed, to clarify and update the SR for the ESF atmosphere cleanup systems vill not increase the probability of.a malfunction of equipment important to safety. The SR change does not alter the safety function of the ESF atmosphere cleanup systems. Redundancy and single failure assumptions are not affected by this change and remain valid.
(10CFR50.59(a)(2)(1))
Revising the TS, as proposed, to clarify and update the SR for the ESF atmosphere cleanup systems vill not increase the consequences of a malfunction of equipment important,to safety. Clarification and updating of the test requirements and acceptance criteria vill not affect any USAR analysis assumptions for operation of systems or components important to safety. (10CFR50.59(a)(2)(1))
Revising the TS. as proposed, to clarify and update the SR for the ESP atmosphere cleanup systems vill not create the possibility for an accident of a different type than any previously evaluated in the USAR. There are no equipment modifications to the ESF atmosphere cleanup systems associated with this change. The clarification and updating of the test procedure and acceptance criteria does not introduce any new failure modes.
Revising the TS, as proposed, to clarify and update the SR for the ESF atmosphere cleanup systems vill not create the possibility of a malfunction of a different type than any evaluated previously in the USAR. System operation and component performance vill not be changed and the existing l assumptions of the USAR analysis remain valid. (10CFR50.59(a)(2)(ii)) l Revising the TS, as proposed, to clarify and update the SR for the ESF atmosphere cleanup systems vill not reduce the margin of safety as defined in the bases for any Technical Specification. Surveillance testing is not i specifically mentioned in the TS base; for ESF atmosphere cleanup systems. l The operability of these systems, as discussed in the TS bases, is ensured by the continued performance of the SR (10CFR50.59(a)(2)(iii))
CONCLUSION Based on the above evaluation, the proposed TS revision does not constitute an unreviewed safety question.
Docket No. 50-346 Licsnsa No. NPF-3 Serial'Nc. 1494 Attachment 1 Page 8 REFERENCES
- 1. Davis-Besse Nuclear Power Station, Unit No. 1, Operating License, Appendix A, Technical Specifications
- 2. Davis-Besse Nuclear Pover-Station, Unit No. 1, Updated Safety-
. Analysis Report, July 1987
- 3. NRC Generic Letter No. 83-13; dated March 2,1983;
Subject:
Clarification of Surveillance Requirements for HEPA Filters and Charcoal Adsorber Units-in the Standard Technical Specifications on ESF Cleanup Systems
- 4. NRC Regulatory Guide 1.52, Revision 1, dated' July 1976; and Revision 2, dated March 1978; Design, Testing, and Maintenance Criteria for Post Accident Engineered-Safety-Feature Atmosphere Cleanup System Air Filtration and Adsorption Units of Light-Vater-Cooled Nuclear Power Plants
- 5. American National Standard ANSI /ASME N510-1975 and ANSI /ASME N510-1980, Testing of Nuclear Air-Cleaning Systems
- 6. NUREG-0136, Safety Evaluation Report by the Office'of Nuclear Reactor Regulation, United States Nuclear Regulatory Commission, in the matter of Toledo Edison Company, Cleveland-Illuminating Company, Davis-Besse Nuclear Power Station, Unit 1, Docket No. 50-346, December 1976
- 7. Davis-Besse Nuclear Power Station, Unit No. 1, Final Safety Analysis Report, March 1973 l
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Docket No, 50-346 Licensa No. NPF-3 Attachment 2 Page 1 SIGNIFICANT HAZARDS CONSIDERATION DESCRIPTION The purpose of this Significant Hazards Consideration is to review the proposed revisions to the Davis-Besse Nuclear Power Station (DBNPS), Unit No. 1, Technical Specifications (TS) in accordance with the requirements of 10CFR50.92 to ensure that a significant hazards consideration does not exist.
The changes to the DBNPS TS Surveillance Lequirements (SRs) are proposed to clarify the testing requirements and update the references for High Efficiency Particulate Air (HEPA) filters and charcoal adsorber units in Engineered Safety Feature (ESP) atmosphere cleanup systems.
The following ESF systems and associated TS Surveillance Requirements are affected by this revision:
DBNPS ESF ATMOSPHERE CLEANUP SYSTEMS DENPS TS Hydrogen Purge System (HPS) SR 4.6.4.4 Emergency Ventilation System (EVS) SE 4.6.5.1 Control Room Emergency Ventilation System (CREVS) SR 4.7.6.1 These TS SRs do not clearly reflect the relationship between the guidance provided in Regulatory Guide 1.52, Revision 2, (Ref. 4), and ANSI N510-1975 (Ref. 5), the testing requirements of the HEPA filters and charcoal adsorber units. -
The existing TS Surveillance Requirements state that,
...the system satisfies the in-place testing acceptance criteria and uses the )
test procedures of Regulatory Positions C.5.a, C.5.c, and C.S.d of Regulatory i Guide 1.52, Revision 1, July 1976..."
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Regulatory Guide 1.52 requires in-place testing of HEPA filters and charcoal
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adsorber units. The in-place Dioctyl Phthalate-(D0P) penetration and bypass leakage testing acceptance criteria for the HEPA filters is 0.05 percent at )
t rated flov. Based on this criteria an ESF air filtration system is considered to varrant a 99 percent removal efficiency for particulates in accident dose evaluations. The in-place gaseous halogenated hydrogen refrigerant bypass leakage testing acceptance criteria specified by Regulatory Guide 1.52 for charcoal adsorber units is also 0.95 percent. A charcoal adsorber unit efficiency is not associated with this in-place bypass testing criteria. The existing TS SR does, however, state:
"...that a laboratory analysis of a representative carbon sample obtained in accordance with Regulatory Position C.6 of Regulatory Guide 1.52, Revision 1, July 1976, meets the laboratory testing criteria of Regulatory Position C.6.a of Regulatory Guide 1.52, Revision 1, July 1976".
Dockst No, 50-346 License No. NPF-3 Attachment 2 Page 2 This requirement assigns a carbon decontamination efficiency based on the carbon bed depth and laboratory testing results.
The existing TS SR requires that in-place DOP testing be in accordance with ANSI N510-1975. This revision of the ANSI is referenced in the existing DBNPS surveillance test procedures for tha HPS, EVS, and CREVS.
NRC Generic Letter No. 83-13 (Ref. 3) was issued to clarify the requirements of, and the relationship between, Regulatory Guide 1.52, Revision 2, ANSI N510-1975, and the NRC staff's assumptions used in its safety evaluations for ESF atmosphere cleanup systems. This document contains revised testing requirements for HEPA filters and charcoal adsorber units to be used in licensee submittals of proposed TS revisions. The revised TS SRs, as stated in Reference 3, allow in-place, bypass leakage and penetration testing I acceptance criteria of 1 percent when a HEPA filter or charcoal adsorber l efficiency of 95 percent or less is assumed in the NRC staff's safety 1 evaluation. NRC Generic Letter 83-13 further states, "Use the value assumed for the charcoal adsorber efficiency if the value for the HEPA filter is .
different from the charcoal adsorber efficiency in the NRC staff's safety !
evaluation."
The DBNPS Final Safety Analysis Report (FSAR) evaluation of the ESP atmosphere cleanup systems assumes a charcoal adsorber efficiency of 95 percent. HEPA filter efficiency is not specifically addressed in the evaluation. The DBNPS l i
FSAR vas reviewed by the Nuclear Regulatory Commission (NRC) and the staff '
issued a Safety Evaluation Report ef. 6) documenting this review. The NRC concurred with the evaluation for the ESF atmosphere cleanup systems contained
-in the FSAR including the 95 percent efficiency assumed for the charcoal adsorber. DBNPS surveillance testing procedures for ESP bypass testing uses an acceptance criteria of less than 1 percent for penetration and bypass leakage.
The changes to the existing TS SRs are proposed to incorporate the following:
- 1. Th generic wording in the surveillance requirements enclosed in NRC Generic Letter 83-13, as applicable to the DBNPS ESF atmospheric cleanup systems and FSAR evaluation assumptions.
- 2. The updating of ANSI N510-1975, referenced in the existing TS SRs, to the current issue, ANSI N510-1980. The ANSI N510-1980 changes have been reviewed for impact on the TS SRs. This edition provides clarification of the testing requirements for ESF atmosphere cleanup systems.
- 3. Editorial changes to provide consistency and clarity for the DBNPS ESF atmospheric cleanup system TS SRs.
- l Docket No, 50-346- I License No. NPF-3 1 Attachment 2 l Page 3 I SYSTEMS AND COMPONENTS AFFECTED Hydrogen Purge System Emergency Ventilation System Control Room Emergency Ventilation System SAFETY FUNCTIONS AFFECTED The EVS is designed to maintain a negative pressure within the negative pressure boundary areas following a loss of coolant accident (LOCA), and to reduce the' fission product content of the system exhaust prior to release through the station vent. Operation of this system reduces the site boundary doses to within the limits of 10CFR100 following a LOCA. The negative pressure boundary areas include the containment annulus, the mechanical penetration rooms, the Makeup Pump room, the Emergency Core Cooling System (ECCS) rooms and the Decay Heat Removal cooler room. The EVS consists of two redundant fan-filter trains. The filter bank consists of a prefilter, a HEPA filter and two charcoal adsorber units. USAR Section 6.2.3.1 discusses the design bases for the EVS. The two redundant EVS subsystems are provided with prefilters, HEPA filters and charcoal adsorber units to remove airborne particles, methyl iodine and elemental iodine contaminants resulting from a LOCA. Per the USAR, the filters have a total efficiency not less than 95 percent. 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 percent for releases to the station vent.
The 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 System. The filter package consists of a demister, heater, and filter unit. The HPS filter package consists of two HEPA filters and one charcoal adsorber. USAR Section 6.2.5.1 discusses the design bases for the HPS. The scenario of hydrogen purging for containment hydrogen control is evaluated for two cases; (1) filter removal efficiency of 95 percent for all forms of iodine, and (2) no iodine removal by the filters. The flow rate during purging for either case is assumed to be the HPS rated flow rate of 100 sefm. )
1 The CREVS is designed to provide filtered and conditioned air to the control room in the event of high radioactivity or toxic airborne contaminants. This ensures that control room conditions do not affect control room equipment and habitability for control room personnel during and following all credible accident conditions. Operability of CREVS, in conjunction with other control l
Docket No, 50-346 l License No. NPF-3 Attachment 2 Page 4 j room design provisions, is based on limiting control room personnel exposure consistent with the requirements of General Design Criteria 19 cf_ Appendix A ,
of 10CFR50. Following a LOCA or toxic leak, the normal control room l 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. USAR Section 9.4.1.1 discusses the design bases for the CREVS. The total efficiency of the filters is not less than 95 percent. The USAR Chapter 15 analyses for a LOCA assumes a CREVS charcoal adsorber unit efficiency of 95 percent for elemental, particulate and organic material.
EFFECTS ON SAFETY The ESF atmosphere cleanup systems are periodically tested to assure operability per the TS requirements. HEPA filter penetration testing is required to provide an indication of the installed filter efficiency originally established by factory testing and reveal the presence of leaks in the system. Charcoal adsorber penetration testing indicates leak-tightness of the installed assembly. Efficiency of the in-place charcoal adsorber is inferred by laboratory analysis of a representative carbon sample.
NRC Generic Letter 83-13 establishes an in-place penetration and bypass leakage test acceptance criteria of less than 1 percent when a charcoal adsorber efficiency of 95 percent is assumed in the NRC staff's safety evaluation. It also references sections of Regulatory Guide 1.52, Revision 2, March 1978 for test procedure guidance (C.5.a. C.5.c, C.S.d), carbon sampling for laboratory analysis (C.6.b), and laboratory testing criteria (C.6.a).
ANSI N510-1975 is referenced for in-place leak testing of HEPA filters with D0P aerosol and charcoal adsorbers with a halogenated hydrocarbon retrigerant test gas.
The proposed revisions to the DBNPS ESF atmosphere cleanup system TSs for HPS (SR 4.6.4.4), EVS (SR 4.6.5.1) and CREVS (SR 4.7.6.1) are evaluated belov for impact on the USAR analyzed events.
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- 1. Revised TS SR votding in accordance with NRC Generic Letter 83-13.
TS Section Affected: SR 4.6.4.4b.1, SR 4.6.5.lb.2, SR 4.7.6.1c.2 The in-place penetration and bypass leakage testing acceptance l criteria of less than 1 percent is in accordance with the charcoal-adsorber efficiency of 95 percent assumed in the USAR evaluation. J Performance of testing using the test procedure guidance in Regulatory Position C.5.a, C.S.c an/ C.5 d of Regulatory Guide 1.52, Revision 2, March 1978 neither alters the surveillance test requirements, nor affects the USAR evaluation. Additional guidance and clarification of in-place testing criteria is provided by l reference to these regulatory positions. I l
Docket No, 50-346
. License No. NPF-3 Attachment 2 Page 5 TS Section Affected: SR 4.6.4.4b.2, SR 4.6.4.4c, SR 4.6.5.1b.3, SR 4.6.5.1c, SR 4.7.6.lc.3, SR 4.7.6.1d A carbon sample obtained in accordance with Regulatory Position C.6.b of Regulatory Guide 1.52, Revision 2, March 1978, does not alter the surveillance. test. requirements or affect ~the USAR evaluation. The change clarifies the requirements.for replacement oof the activated carbon adsorber section with new, unused activated carbon.
The laboratory testing criteria of Regulatory Position C.6.a of Regulatory Guide 1.52, Revision 2, March 1978, for a methyl iodine penetration of less than 1 percent does not alter the surveillance test requirements or affect the USAR evaluation. The change specifically states the penetration acceptance criteria and also clarifies the requirements for new activated carbon.
TS Section Affected: SR 4.6.4.4e, SR 4.6.5.le, SR 4.7.6.lf Verification that, after each complete or partial replacement of a HEPA filter bank, the bank satisfies the in-place penetration testing and bypass leakage acceptance criteria'of less than 1 percent for a DOP test aerosol, is in accordance with the charcoal adsorber efficiency of 95 percent assumed in the USAR evaluation.
TS Section Affected: SR 4.6.4.4f, SR 4.6.5.1f, SR 4.7.6.lg Verification that, after each complete or partial-replacement of a charcoal adsorber unit bank, the charcoal bank satisfies the in-place penetration and bypass leakage testing acceptance criteria of less than 1 percent for a halogenated hydrocarbon refrigerant test gas, is in accordance with the charcoal adsorber efficiency of 95 percent assumed in the USAR evaluation.
- 2. Revised TS SR reference of ANSI N510-1975 to the current issue, ANSI N510-1980.
TS Section Affected: SR 4,6.4.4d.2 l
Testing system heaters in accordance with ANSI N510-1980 the current approved revision, does not alter tha requirements of the 1975 revision and provides consistency with the reference of the 1980 revision in other sections of the proposed TS revision. This change does not affect the USAR evaluation.
TS Section Affected: SR 4.6.4.4e, SR 4.6.5.le, SR 4.7.6.lf DOP testing acceptance criteria in accordance with ANSI N510-1980, l the currently applicable revision, provides clarification of the l requirements of the 1975 revision. This change does not affect the i USAR evaluation. '
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Dockst No, 50-346' )
License No. NPF-3 l
' Attachment 2 l Page 6
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, TS Section Affected - SR 4.6.4.4f, SR -4.6.5.lf, !HL 4.7.6.lg
- Halogenated hydrocatbon' refrigerant gas testing in accordance.with ANSI N510-1980, the currently applicable revision,-provides clarification.of the requirements of the 1975 revision. This change does not affect the USAR evaluation.
TS,Section Affected: -!Ht 4.6.5.lb.4, SR 4.7.6.1c.4-Verification of system flovrate in accordance with ANSI.N510-1980, the currently applicable. revision, provides additional procedure information and clarification of the test requirements stated'in the 1975 revision. The system flovrate is as stated in the USAR analysis.
- 3. Revised TS SRs to incorporate editorial clarifications. l TS Section Affected: SR 4.6.4.4b'.2, SR 4.6.5.1b.3, SR 4.6.5.1c, SR 4.7.6.1c.3 The deletion of the specific footnote requirements is in accordance
.vith Revision 2, dated. March 1978, of Regulatory Guide 1.52 for testing of new; activated carbon. The specific testing requirements-
~for activated carbon have been deleted from this footnote'and incorporated by reference into the appropriate TS. sections. .This change does not alter the surveillance test requirements.
TS Section Affected: '!Ht 4.6.4.4d.1, SR 4. 6.5.1d , SR 4. 7.6. la ,
SR 4.7.6.le These are miscellaneous editorial changes to the SRs which do not. '
affect the USAR evaluation.
TS Section Affected: SR 4.6.5.lb.1, SR 4.7.6.lc.1 ,
The deletion of this section is editorial in nature. The !
requirements of these sections are adequately stated in the proposed j revisions to TS sections SR 4.6.5.1b.2 and SR 4.7.6.1c.2, i respectively. This change does not affect the USAR evaluation.
SIGNIFICANT HAZARDS ANALYSIS The Commission has provided standards in 10CFR50.92(c) for determining whether a significant hazards consideration exists. A proposed amendment to an Operating License for a facility involves no significant hazards consideration if operation of the facility in accordance with the proposed amendment vould not: (1) involve a significant increase in the probability or consequences of an accioent previously evaluated, (2) create the possibility of a new or different kind of accident from any accident previously evaluated, or (3) ;
involve a significant reduction in a margin of safety. Toledo Edison has I reviewed the proposed change and determined that:
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Docket No, 50-346 License No. NPF-3 Attachment 2 Page 7 The proposed amendment does not involve a significant increase in the probability or consequences of an accident previously evaluated because the ESF atmosphere cleanup systems are standby systems designed to mitigate the consequences of certain design basis accidents. The SR changes clarify testing requirements and update regulatory and industry testing references for HEPA filters and charcoal adsorber units in ESF atmosphere cleanup systems.
Similarly, the SR changes to these systems do not increase the probability or consequences of a previously evaluated accident. (10CFR50.92(c)(1)).
The proposed amendment does not create the possibility of a new or different kind of accident from any previously evaluated because there are no equipment modifications to the ESF atmosphere cleanup systems associated with this change. Similarly, the clarification and updating of the test procedure and acceptance criteria does not introduce any new or different kind of accident.
The proposed amendment does not involve a significant reductior in the margin of safety because system operation and components vill not be changed and the SRs are being updated consistent with NRC guidance. (10CFR50.92(c)(3)).
CONCLUSION Based on the above, it is concluded that the proposed Technical Specification changes do not involve a Significant Hazards Consideration.
REFERENCES
- 1. Davis-Besse Nuclear Power Station, Unit No. 1, Operating License, Appendix A, Technical Specifications
- 2. Davis-Besse Nuclear Power Station, Unit No. 1, Updated Safety Analysis Report, July 1987
- 3. NRC Generic Letter No. 83-13; dated March 2, 1983; Subj ect: Clarification of Surveillance Requiroments for HEPA Filters and Charcoal Adsorber Units in the Standard Technical Specifications on ESF Cleanup Systems
- 4. NRC Regulatory Guide 1.52, Revision 1, dated July 1976; and Revision 2, dated March 1978; Design, Testing, and Maintenance Criteria for Post Accident Engineered-Safety-Feature Atmosphere Cleanup System Air Filtration and Adsorption Units of Light-Vater-Cooled Nuclear Power Plants
- 5. American National Standard ANSI /ASHE N510-1975 and ANSI /ASHE N510-1980, Testing of Nuclear Air-Cleaning Systems
- 6. NUREG-0136, Safety Evaluation Report Related to the Operation of Davis-Besse Nuclear Power Station Unit 1.
- 7. Davis-Besse Nuclear Power Station, Unit No. 1, Final Safety Analysis Report, March 1973
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