ST-HL-AE-5500, Forwards Addl Info to Support Staff Review of 960815 TS Change Request Deleting SR 4.7.7.e.5.Copy of USQ Evaluation 95-0027 Addressing Removal of Toxic Gas Monitoring Sys Encl
| ML20134G089 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 10/31/1996 |
| From: | Thomas S HOUSTON LIGHTING & POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20134G092 | List: |
| References | |
| ST-HL-AE-5500, NUDOCS 9611130039 | |
| Download: ML20134G089 (30) | |
Text
The Light c o m p a n y S uth Texas Project Electric Generating Station liouston Lighting & Power _
P. O. Box 289 Wadsworth, Texas 77483 October 31, 1996 ST-IIL-AE-5500 File No.: G20.01 G21.01 10CFR50.90 t
U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D. C. 20555 l
4 South Texas Project Units 1 and 2 Docket Nos. STN 50-498, STN 50-499 i
Proposed Revision to Technical Specifications Removing Surveillance Reauirement 4.7.7.e.5 - Additional Information
Reference:
Correspondence from T. H Cloninger to Document Control Desk, dated August 15,1996 (ST-HL-AE-5403)
Pursuant to a request from Thomas Alexion, the South Texas Project submits the attached copy of Unreviewed Safety Question Evaluation #95-0027 addressing removal of the Toxic Gas Monitoring System. The evaluation is provided to support the staff's review of the referenced Technical Specification change request deleting surveillance requirement 4.7.7.e.5.
If there are any questions, please contact either Mr. P. L. Walker at (512) 972-8392 or me at (512) 972-7162.
S. E. Thomas
- Manager, Design Engineering PLW/lf
Attachment:
Unreviewed Safety Question Evaluation #95-0027
@[
j 9611130039 961031 PDR ADOCK 05000498 P
PDR Project Manager on BehaH of the Participants in the south Texas Project MISC-W3300 w STI:
Houston Lighting & Power Company ST-HL-AE-5500 South Texas Project Electric Generating Station File No.:
G20.01 GG21.01 Page 2 Leonard J. Callan Rufus S. Scott Regional Administrator, Region IV Associate General Counsel U. S. Nuclear Regulatory Commission Houston Lighting & Power Company 611 Ryan Plaza Drive, Suite 400 P. O. Box 61067 Arlington, TX 76011-8064 Houston, TX 77208 Thomas W. Alexion Institute of Nuclear Power Project Manager, Mail Code 13H3 Operations - Records Center U. S. Nuclear Regulatory Commission 700 Galleria Parkway Washington, DC 20555-0001 Atlanta, GA 30339-5957 David P. Loveless Dr. Bertram Wolfe Sr. Resident inspector 15453 Via Vaquero c/o U. S. Nuclear Regulatory Comm.
Monte Sereno, CA 95030 P. O. Box 910 Bay City, TX 77404-0910 kicinard A. Ratliff Bureau of Radiation Control J. R. Newman, Esquire Texas Department of Health Morgan, Lewis & Bockius 1100 West 49th Street 1800 M Street, N.W.
Austin, TX 78756-3189 Washington, DC 20036-5869 J. R. Egan, Esquire i
M. T. Hardt/W. C. Gunst Egan & Associates, P.C.
City Public Service 2300 N Street, N.W.
P. O. Box 1771 Washington, D.C. 20037 San Antonio, TX 78296 J. C. Lanier/M. B. Lee U. S. Nuclear Regulatory Commission City of Austin Attention: Document Control Desk Electric Utility Department Washington, D.C. 20555-0001 721 Barton Springs Road Austin, TX 78704 Central Power and Light Company J. W. Beck ATTN: G. E. Vaughn/C. A. Johnson Little Harbor Consultants, Inc.
P. O. Box 289, Mail Code: N5012 44 Nichols Road Wadsworth, TX 77483 Cohassett, MA 02025-1166 i
OR G NAL er Licensing Doc. Change Request: _ CN-1979 I3ev. Q.
Page J,1 of OPGP05-ZA-0002 Rev.2 3
10CFR50.59 Evaluations Forrn 2 Unreviewed Safety Question Evaluation Forin Page 1 of 4 Unreviewed Safety Question Evaluation # 95-0027_
. Revision No. 00_ _
ORIGINATING DOCUMENT: CN-1979
~
REV. NO. _0Q.
NOTE: Attach 10CFR50.59 Screening Form or License Compliance Review Form to this USQE.
A.1 1
Does the subject of this evaluation increase the probability of O YES E NO occurrence of an accident previously evaluated in the Safety Analysis Report?
Bases: The SAR evaluated the ofpbability of accidents related to nostulated relemes of hazardous chemicals onsitemijdthin a five mile radius of STPEGS.Comorebensive l
analyses were ocrformed iy evilyg.the effects of a postulated release of potentially hazardous chemicals which gghwa threat to mntrol room habitability. De SAR evaluation was based on the ongga! Oncite and Offsite Toxic Gas Analyses. De results of the latest revision to these annivses shcw that none of the notentially ha7ardont chemicals utilized onsite or in the surTounding 5 mile radius pose a credible hazard to STPEGS. The results of the latest analyses demonstrate a decrease in the probability of occurrence of an accident previously evaluated.
p II Does the subject of this evaluation increase the consequences O YES E NO Q
of an accident previously evaluated in the Safety Analysis Report?
Bases: The subiect chance revises the monitorine recuirements for potentially hazardo.g3 N
chemicals based on the latest revision of the Onsite and offsite Toxic Gas Analyses. De Q
results of these analyses demonstrate that deletion of the chemical detection system will i
not increase the consequences of an accident evaluated in the SAR since cone of the chemicals considered cose a credible hazard to STPEGS..
Li"i III Does the subject of this evaluation increase the probability of O YES E NO g
occunence of a malfunction of equipment important to safety previously evaluated in the Safety Analysis Report?
Bases: The subiect CN eliminates the recuirement for instrumentation to detect. alarm.
pnd automatically isolate the control room in the event of hich concentration of certa _lr.1 hazardous chemicals. The latest analyses determined that none of the votentia!!v bazardous chemicals considered nose a credible hazard to STPEGS. Therefore. the b'
eauipment of concern iLno longer important to safety and does not increase the I
probability of occurence of a malfunction of cauipment important to safety.
IV Does the subject of this evaluation increase the consequences O YES E NO O
of a malfunction of equipment impetant to safety previously evaluated in the Safety Analysis r4 ut?
Bases: The subiect CN eliminates the reouirement of monitorine for bazardous chemicals from the SAR and TRM based on the latest analyses. Since the,
O hiittumentation is no loneer imoortant ta safety and will be isolated from all safety Cl related coulement: consecuences of a malfunction of this instrumentation no longer need to be evaluated in the Safety Analysis Report.
,e
. = =
.-emm.==em.4e me s
.e.+=
.-e..
aw..
..m.e a.s
ORIGINAL Licensing Doc. Change Request: CN-1979 Rev. _Q_
Pcce.f(,of OPGP05-ZA-0002 Rev.2 10CFR50.59 Evaluations i
i Form 2 Unreviewed Safety Question Evaluation Form Page 2 of 4 A.2 I
Does the subject of the eviluation create the O YES E NO possibility of an a ident of a different type than any previously evaluated in the Safety Analysis Report?
Bases: The Toxic Gas Monitorine system was provided to protect against 1 anidous.
toxic tas releases only. The revised analysis prove none of the h=dous chemicals l
evaluated pose a credible threat to STPEGS. therefore. no new accidents have been created.
i 4
II Does the subject of this evaluation create the O YES E NO possibility of a different type of malfunction than any previously evaluated in the Safety Analysis Report?
Bases: Disabling of the chemical detection system. includine all interfaces with Engineered Safety Features, will not create the possibility of a malfunction of a different tvoc than previously evaluated.
i A.3 I
Does the subject of this evaluation reduce the margin O YES E NO of safety as defined in the basis for any Technical Specifications?
Bases:* The sublect CN eliminates the renuirement of monitorine for hazardous chemicals from the SAR and TRM based on the latest revision to the Onsite and Offsite Toxic Oas Analyses. The original analyses provided the basis for reauiring a chemical detection system based on the existine chemical hazards to STPEGS. The latest revision to these analyses show that none of the chemicals considered pose a credible hazard to STPEGS. therefore, the basis for reauiring a chemical detection system no longer exists.
Elimination of the chemical detection system based on. current chemical hazards to STPEOS does not reduce the marcin of safety reauired to maintain control room babitability. Technical Specification 4.4.7 Surveillance e.5 requires testine of CRE IIVAC damoer response time. This test is moverned by Plant Surveillance Procedure OPSP-HE-0002 Rev. 9. The design channe to disable the toxic ras analyzers does not inhibit performance of this test as written. Therefore. there is no decrease in martin of safety as defined in the basis for Techrdcal Soecification 4.4.7 Surveillance e.5.
O
ORIGINAL Licensing Doc. Change Request: CN-1979 Rev. O Page [ of I
OPGP05-ZA-0002 Rev. 2 10CFR50.59 Evaluations Form 2 Unreviewed Safety Question Evaluation Form Page 3 of 4 SAFETY EVALUATION SUhBIARY The subject of this evaluation involves a change to the STPEGS Updated Final Safety Analysis (UFSAR) and Technical Reauirements Manual (TRM). Channes are beine made to eliminate all references in the UFSAR to the Toxic Gas Monitorine System as well as climinatinc monitoring LegyDtrents frotn the TRM based on the latest revisions (Revision 5 &J5) to the Onsite (NC9015) and Offsite (NC9006) T' xic Gas' Analyses. ' Tiiese analyses consist of a comorebensive 6
evaluation of all chemicals utilized onsite and stored or transoorted within a five mile radius of STPEGS. The evaluations consist of extensive screening. dispersion analysis and probability analysis in accordance with the guidance Riven in Regulatory Guide (RG) 1.78. methodology presented in NUREG-0570. and_ptilize the most current /anoticable toxicity limits of notentially jtazardous chemicals. The results of these analyses prove that none of the chemicals considered pose a credible bazard to STPEGS. Therefore, climination of the reautrement to maintain instrumentation to alann and isolate the control room upon detection of certain chemicals does not compromise control room babitability.
O
ORIGINAL Licensing Doc. Change Request: CN-1979 Rev._Q Page & of O
ororos-z^.ooo2 nev. 2 10CFR50.59 Evaluations Page# of/ph3 f
Form 2 Unreviewed Safety Question Evaluation Form f
14 B.
1.
XXX All of the above questions were answered NO; therefore, the originating document does pM involve an Unreviewed Safety Question.
2.
One or more of the above questions was marked YES; therefore, the originating document involves an Unreviewed Safety Question. The originating document, as presented, shall NOT be implemented without prior approval by the NRC. Provide a recommendation for disposition of the Unreviewed Safety Question below Refer to OPGP05-ZA-0004 for processing licensing amendments. Further processing of this farm to the PORC, Plant Manager and NSRB is not required. Notify Procedure Control that the evaluation involved an Unreviewed Safety Question so that Procedure Control can close the USQE number.
RECOMMENDED DISPOSITION: These channes do not involve an Unreviewed Safety Ouestion.
therefore approval of this eval glion is recommended.
s
/%
.b PREPARED BY:
Mb-84'- Pf~~
TRIGINA' TOR - Tim L. Locker Date REVIEWED BY:
Mr##
[w
[ f$ - Y 7 DilALIFIED REVIEWER Date 8' 8 3 APPROVED BY:
~ DEPARTMENT MANAGER Date PORC MEETING NO.
WN D.
<i'9' W Date
[~~
APPROVED BY:
N PLANT MANAGER Date REMARKS
ORIGINAL Licensing Doc. Change Request: _CN 1979 Rev._Q.
Page fq. of O
ocoros-z^.ooo2 nev. 2 10CFR50.59 Evaluations Form i 10CFR50.59 Screening Form Page 1 of 3 O UNIT #1 E OFSAR CN O DESIGN CHANGB~
E OTHER TRM Channe O UNIT #2 E BOTH ORIGINATING DOCUMENT NO. CN-1979 ilEV. NO._06_
DESCRIPTION OF CHANGEi The sublect Chance Notice (CN) is being issued to revise the Toxic Gas monitorinn reauirements described in the UFSAR and detailed in the Technical Reauirements Manual (TRM) to reflect the results of latest revisions of the Onsite and Offsite Toxic Gas Asialyses. NC9015 and NC9006. respectively. The revised analyses evaluate all chemicals currently stored at and shipped to and from STPEGS and surrounding facilities within a five mile radius to determine the effects a posjylaJt d release of hazardous chemicals would have on control room habitability. The revised analyses og in accordance with the enidance riven in Regulatory Guide (RG) 1.78 and methodology presented in NUREG-0570. Revisions 5 & 6 of these analyses show that none of the chemicals utilized onsite. at snrrounding facilities or transoorted within five miles of the site cose a credible hazard to STPEGS. The subiect _CN is issued to revise the UFSAR by dRletint all references to the toxic ras monitorine system and to remove the monitoring scouirements froni the TRM based on the results of the analyses.
PRELIMINARY SCREENING YES NO
- 1. Does the proposed change represent a change to the Plant Technical Specifications?
O E
- 2. Is an Unreviewed Safety Question known to be associated with the subject change?
O N
NOTE: If "YES" to either questions 1 or 2 refer to OPGP05-ZN-0004.
Does the proposed change represent:
- 3. A change to only correct a typographical, editorial or drafting error?
O E
- 4. A change which is identical to and addressed in its entirety by an existing approved 10CFR50.59 Screening /USQE or NRC approved licensing submittal?
O E
- 5. A spare or replacement part/ component change with an equivalent part/ component?
O E
(See Section 2.3 for a definition of equivalent)
- 6. A configuration change within existing design specifications?
O E
If all answers to the above questions are "NO" perform the final screening and mark N/A in the approval blocks below.
If the answer to any question (3) through (6) is "YES" a final screening is not necessary.
Sign approval blocks below and discard pages 2 through 3.
Provide a justification and references if any of items (3) through (6) is answered "YES".
N/A
'O Prepared by:
N/A Originator Date Approved by:
N/A Qualified Reviewer Date
ORIGINAL Ucensing Doc. Change Request: _ CN-1979 Rev. _0_
Page.JZ. of O
ororos-z^.ooo2 aev. 2 10CFR50.59 Evaluations Form 1 10CFR50.59 Screening Form Page 2 of 3 FINAL SCREENING la response to the questions below, if the change involves sometblog that is not described in the SAR and is not part of the licensing basis, the "N_Q" is appropriate. However, this decision must be clearly documented with adequate technicaljustification for each question and the sections reviewed of applicable documents and applicable attributes reviewed should be indicated. The listing of attributes and documents for 10CFR50.59 screening can be found in Addendum 5.
Inter-discipline Coordination Required?
E YES O NO If "yes", obtalo appropriate concurrence.
O Risk and Reliability Analysis O Thermal Hydraulics O Reactor Engr.
O Civil O Mech ~
O Elect
Licensine '
O YES NO 1.
Does the subject of this review involve a change to the facility as described in the Safety Analysis Report? _ Based on the results of Revisions 5& 6 to the Onsite and Offsite Toxic 5
O Gas Analysis the monitoring recuirements discussed in the UFSAR and Technical Reauirements Manual (TRM) are being deleted. Since a cbante is beine made to the facility as desenbed in the UFSAR. a USOE will be reauired. Refer to USOE 95-0027 for further eyaluation of these chanam a
Affected UFSAR Section(s); _2.2.3. 6.4 and 9.4 2.
Does the subject of this review involve a change to the procedures as described in the Safety Analysis Report? Refer to OPAP01-ZA-0103. Procedures that reauire revision as O
E a result of deletine monitoring reauirements are not described in the UFSAR.
i i
0 1
i 0RIGINAL Licensing Doc. Change Request: __CN-19 79 Rev._0_
Page12. of
- O ocoros-z^.ooo2 nev. 2 10CFR50.59 Evaluations Form 1 10CFR50.59 Screening Form Page 3 of 3 YES NO i
3.
Does the subject of this review propose the conduct of tests or experiments not described O
E i
in the Safety Analysis Report? The subiect channe involves deletion of Toxic Gas Monitorian reauirements and does not oropose the conduct of any new tests or experiments.
4.
Does the proposed change affect condidons or bases assumed in the Safety Analysis E
O Report or safety-related functions of equipment / systems, even though the proposed change does not entail any physical change in existing structures, systems, or procedures as described in the SAR? The subject chance nodce to the UFSAR and TRM involves a change to the bases assumed in the UFSAR for reauiring instrumentation to detect byardous chemicals which could have adverse affects on control room habitability. Due to channes in the cuantities and tvoes of potendally hazardous chemicals stored at and O
transported to and from STPEGS and surroundine facilities the potential harards have changed. The oririnal bases were determined by the previous revisions to the analyses
~
which identified potential _ hazards to STPEGS based on the conditions at the time of those.
revisions. Revisions 5 & 6 to the Onsite and Offsite Toxic Gas Analyses show that nonc of the current chemicals _ considered pose a credible bazard to control room habitability.
Therefore. the latest analyses provide a new bases for determinion the Toxic Gas Monitorine reauirements at STPEGS.
j Refer to USQE No.: 95-0027 If any answer is affirmative, complete the screening form and perform an Unreviewed Safety Question Evaluation.
If all answers are negadve, no Unreviewed Safety Question Evaluadon is required.
Prepare by:
dh 8 ff" Originator - Tim L. Locker Date Approved by:
/2.a.-, / [d b #~JT'
/ f / Qualified Reviewer Date O
l ORIGINAL OPGP05-ZN-0004 Rev.1
{
Changes to Licensing Basis Docunients and Amendments to the Operating License 1
CN-1979 Licensing Document Change Request Page _f._ of /__O6_
}
4 4
i i
1 i
i i
i Change Notice CN-1979 i
Deletion of Toxic Gas Monitor references in the UFSAR and monitoring j
requirements from the Technical Requirements Manual (TRM) 4 I
i i
ORLGINAL OPGP05-ZN-0004 Rev.1 Changes to Licensing Basis Documents and Amendments to the Operating License Data Sheet 1 Licensing Document Change Request Page A of Change Number 1979 Date 7/10/95 I
I Originator Tim L. Locker Dept DED/l&C Change Description f,
Revise Uodated Final Safety Analysis Reoort (UFSAR) and the Technical Recuirements Manual (TRM) to incorporate chances in the Toxic Gas Monitorina reauirements at STPEGS based on th_g latest revision of the Onsite and Offsite Toxic Gas Analyses (NC9015 and NC9006 Revision 6).
Initiating Documentation Onsite Toxic Gas Analysis NC9015 Revision 6, Offsite Toxic Gas Analysis NC9006 Revision 6.
USOE Number 95-0027 Unit (s)
Unit 1 Unit 2 nu vedakJ Bhohs e
tation Status:
Unit 1 Completion Date mg Unit 2 Completion Date y
m 3r R viewed and Approved 2B g Engineer, Nuclear Licensing Date R viewed and Approved
- ate (ER, UFSAR 2.1, 2.2, 2.3)
PEanager, Technica? Services Department D
Reviewed by
}jh (OQAP changes only)
General Manager, Nuclear Assurance Date Cp. % - BBM This Form when completed, shall be retained for the life of the plant.
-e
i l
0PGP05-ZN-0004 Rev.1 Changes to Licensing Basis Documents and Amendments to the Operating License CN-1979 Licensing Document Change Request Page.,3__ of ___
l Order / Layout of Chance Package Section 1
> Description of Change Section 2
> Description of Current Requirements and Bases Section 3
> Summary of Analyses Section 4
> Summary of Design Change to Disable the Analyzers Section 5
> 50.59 Evaluation /Unreviewed Safety Question Evaluation Section 6 UFSAR Sections - including associated revisions Section 7
> Affected TRM Pages Section 8
> References
l OPGP05-ZN 0004 Rev.1 Changes to Licensing Basis Documents and Amendments to the Operating License CN-1979 Licensing Document Change Request Page_i,of_,,_
SECTION 1 Description of Change i
The purpose of this change is to revise Licensing-based documents. 'Ihe subject of this change involves a revision to the STPEGS Updated Final Safety Analysis (UFSAR) and Technical Requirements Manual (TRM) based on the latest revisions (Revisions 5 & 6) to the Onsite (NC9015) and Offsite (NC9006) Toxic Gas Analyses. These analyses consist of a comprehensive evaluation of all chemicals utilized onsite and stored or transported within a five mile radius of the South Texas Project Electric Generating Station. The evaluations consist of extensive screening, dispersion analysis and probability analysis in accordance with the guidance given in Regulatory Guide (RG) 1.78, methodology presented in NUREG-0570, and utilize the most current / applicable toxicity limits of potentially hazardous chemicals. The results of these analyses demonstrate that none of the chemicals considered pose a credible hazard to STPEGS. Therefore, elimination of the requirement j
to maintain instrumentation to alarm and isolate the control room upon detection of certain chemicals 1
does not compromise control room habitability. The UFSAR is revised to reflect the results of the revised analyses. The TRM is revised to remove the Limiting Condition for Operation and Surveillance Requirements for Chemical Detection Systems.
The Chemical Detection Systems for each unit will be disabied per Design Change Package DCP#94-3615-10.
i OPGP05-ZN-0004 Rev.1 Changes to Licensing Basis Documents and Amendments to the Operating License CN_1979 Licensing Document Change Request Page [ of _
SECTION 2 Toxic Gas Monitorine Reauirements and Bases Original licensing basis that determined a need for Toxic Gas Monitoring:
Criterion 4. " Environmental and missile design bases," of Appendix A " General Design Criteria for Nuclear Power Plants" to 10CFR50 requires, in part, that structures, systems and components 4
important to safety be designed to accommodate the effects of and to be compatible with the environmental conditions associated with normal operation, maintenance, testing, and postulated accidents. Criterion 19, " Control room," requires that a control room be provided from which actions can be taken to operate the nuclear power unit safely under normal conditions and to maintain it in a safe condition under accident conditions. Release of hazardous chemicals can potentially result in the control room becoming uninhabitable. Regulatory Guide 1.78, " Assumptions for Evaluating the liabitability of a Nuclear Power Plant Control Room During a Postulated Hazardous Chemical Release", describes assumptions acceptable to the Nuclear Regulatory Commission staff for assessing the habitability of the control room during and after a postulated external release of hazardous chemicals and describes criteria that are generally acceptable for the protection of the control room operators.
De Standard Review Plan (SRP) requires that toxic substances stored or transported in the vicinity of a nuclear site which may pose a threat to the plant operators upon a postulated accidental release be identified. He SRP refers to Regulatory Guide 1.78 for determining methods for analyzing the degree of risk and, in general terms, the.various protective measures that could be instituted if the hazard is found to be too great. The protective measures should provide time for personnel in the control room to fit themselves with self-contained breathing apparatus.
During the licensing of the South Texas Project Electric Generating Station (STPEGS), it was determined that six of the chemicals stored at and shipped to and from the Celanese Chemical Company, located almost 5 miles from the plant, pose a potential hazard to STPEGS. An analysis was performed to determine the effects that a postulated release of these chemicals would have on control room habitability. The methods and assumptions of the analysis were in agreement with the guidance given in Regulatory Guide 1.78 and methodology presented in NUREG-0570 and NUREG/CR-1741. The results of the analysis showed:
- 1. Detection, alarm, and automatic isolation were necessary for vinyl acetate and anhydrous ammonia to allow ample time for control room personnel to don protective breathing apparatus.
- 2. Detection and alarm were necessary for hydrochloric acid, acetic acid, acetaldehyde, and naphtha to allow ample time for control room personnel to don protective breathing apparatus.
OPGP05-ZN-0004 Rev.1 Changes to Licensing Basis Documents nnd Amendments to the Opernting License CN-1979 Licensing Document Change Request Page.ff_ of _
SECTION 2 Toxic Gas MonitorinLR.tquirements nnd Bnses Cont'd Redundant chemical detectors are currently located in the outside air intake to the control room envelope to provide automatic isolation from potentially hazardous chemicals in the event of an onsite or offsite chemical spill accident. These same redundant detectors also provide for detection and alarm for specific chemicals.
He South Texas Project Technical Requirements Manual has Limiting Condition for Operation, Action statements for inoperable chemical detection systems, and Surveillance requirements for chemical detection systems.
l
OPGP05-7sN 0004 Rev.1 Changes to Licensing Basis Documents and Amendments to the Operating License CN-1979 Licensing Document Change Request Page,l_ of ___
1 SECTION 3
~
Summary of Analyses Methods and Results l
- Ihe Onsite and Offsite Toxic Gas Analyses, NC9015 and NC9006, respectively, provide the bases for the chemical detection system requirements at the South Texas Electric Generathig Station (STPEGS). These analyses evaluate all chemicals stored at and shipped to and from STPEGS and surrounding facilities within a five mile radius of the STPEGS control rooms to determine the effects a postulated release of hazardous chemicals would have on control room habitability. The analyses are in accordance with the guidance provided in Regulatory Guide (RG) 1.78, NUREG-0570 and
.NUREG-0800, Standard Review Plan, Section 2.2.3.
'Ihe requirements identified in Section 2 of this Change Notice (CN) are based on the results of Revision 4 to the Onsite Toxic Gas Analysis, NC9015, and the Offsite Toxic Gas Analysis, NC9006.
1hese requirements are those currently stated in the UFSAR, and are as follows:
- 1. Detection, alarm, and automatic isolation were necessary for vinyl acetate and anhydrous arnmonia to allow ample time for control room personnel to don protective breathing apparatus.
- 2. Detection and alarm were necessary for hydrochloric acid, acetic acid, acetaldehyde, and naphtha to a110w ample time for control room personnel to don protective breathing apparatus.
Changes in type and quantity of chemicals used onsite and within the surrounding 5 mile radius of STPEGS prompted revision (Rev. 5) to the existing analyses to evaluate the current chemicals hazards to STPEGS. 'Ihe STPEGS Tier Two Report dated Febmary 24,1994 was used to identify all potential onsite chemical hazards while a survey was performed to identify all chemical storage tanks, as well as barge, rail and truck shipments, within five miles of the control room. All chemicals identified were then evaluated for their effect on control room habitability.
NC9006 & NC9015. Revision 5 4
Ihe evaluation consisted of three parts: preliminary screening, dispersion analysis, and probability analysis.
A preliminary screenind was performed which evaluated the chemical storage quantities, shipping frequencies, vapor pressures and toxicity limits in accordance with RG 1.78. Based on RG 1.78, chemicals stored or situated at distances greater than five miles from the control room need not be considered in the analysis. Chemicals whose storage quantity is less than 100 lbs or whose vapor pressure is less than 10 torr at 100*F need not be considered. In addition infrequent chemical shipments need not be considered. No further analysis is required for chemicals with low vapor pressures, low shipping frequencies, small storage quantities, or nonestablished toxicity limits.
Preliminary screening identified chemicals which pose a potential threat to the control room habitability.
=
OPGP05-ZN-0004 Rev.1 Changes to Licensing Basis Documents and Amendments to the Operating License CN-1979 Licensing Document Change Request Page.8__ of _,
SECTION 3 Summary of Analyses Methods and Results _.
A dispersion analysis was performed for all chemicals that pose potential threat to the control room.
A nonisolated control room is considered, and the maximum control room concentration is determined. The dispersion analysis is based on the rupture of the largest storage or shipping container. The stored or shipped quantity is considered acceptable if the maximum concentration of a nonisolated control room is below the toxicity limit or if the control room concentration six minutes after nasal detection is below the toxicity limit. No further analysis is required if the maximum control room concentration is below the toxicity limit. A more detailed dispersion analysis is performed for all chemicals whose control room concentration exceeds the toxicity limit. Nasal detection is considered, and the control room concentration six minutes after nasal detection is determined (six minutes is the time allotted for STPEGS operators to don protective breathing apparatus). No further analysis is required if the six minute concentration is below the toxicity limit.
A crobability analysis is performed for all chemicals whose six minute concentration exceeds the toxicity limit. No monitoring is required for those chemicals whose_ occurrence probability is below
]
the acceptable value, as specified in NUREG-0800. Based on NUREG-0800, Standard Review Plan, i
Section 2.2.3, if the realistic occurrence probability of an event is 104 or less per year, or if the occurrence probability based on conservative assumptions and combined with reasonable qualitative arguments is 104 or less per year, the event occurrence probability is acceptable and no further analysis is required.
Preliminary Screenine Preliminary screening identified 13 offsite chemicals including acetic acid, vinyl acetate, acetaldehyde, and naphtha which required further analysis.
The preliminary screening found that anhydrous ammonia and hydrochloric acid are no longer used at STPEGS or at the Celanese plant. Therefore, ammonia and hydrochloric acid do not present a hazard to control room habitability at STPEGS.
Dispersion Analysis Based on dispersion analysis it was determined that no monitoring was required for all chemicals except vinyl acetate, acetic acid, acetaldehyde, and naphtha.
It was determined that a detector setpoint of 100 ppm was required to alarm and isolate the control room for vinyl ncetate and acetic acid to maintain control room habitability based on the toxicity limits specified in revision 5.
OPGP05-ZN-0004 Rev.1 Changes to Licensing Basis Documents and Amendments to the Operating License CN-1979 Licensing Document Change Request Page.f_ of _.
SECTION 3 Summary of Analyses Methods and Results Probability Analysis The probabilities of causing uninhabitable conditions in the control room due to an accidental release of acetaldehyde and naphtha were determined as detailed below.
Acetaldehyde The dispersion analysis referenced in the previous section is based upon the rupture of one sphere.
For conservatism, it is assumed that the entire released quantity will flash forming an instantaneous puff. 'The results show that the control room concentration, six minutes after nasal detection, is 89 ~
ppm for stability category E. This is below the toxicity limit of 100 ppm (Time Weighted Average TWA). Therefore, only stability categories G and F will cause uninhabitable conditions in the control room.
The probability of causing uninhabitable conditions in the control room due to an accidental release of acetaldehyde is evaluated in accordance with NUREG-0800. Based on design input, computations shew the occurrence probability of stability categories G and F is 0.205, and that of the NNE wind direction is 0.079. These are the stability categories and the wind direction that would cause uninhabitable conditions in the control room. Based on design input the occurrence probability of catastrophic rupture of a pressure vessel is 1x104/ year.
Based on the above, the probability of causing uninhabitable conditions in the control room due to an accidental release of acetaldehyde, P-, is determined as follows.
P,
= Ne, Pma,,,%, P, w
,y Pu %
where Ne, is the number of tanks / vessels, P
,,is the occurrence probability of tank / vessel rupture, P,em,, is the occurrence probability of the stability categories that would cause uninhabitable conditions in the control room, and Pm m._ is the occurrence probability of the wind directions inat would cause uninhabitable conditions in the control room.
P,
= (2) (1x104) (0.205) (0.079) = 3.24x104 Naphtha Naphtha is stored in two tanks contained in the same berm. The two tanks hold 2.4x105 galand 2
0.9x10' gal respectively, and the area of the berm is 180000 ft.
OPGP05-ZN-0004 Rev.1 Changes to Licensing Basis Documents and Amendments to the Operating License CN-1979 Licensing Document Change Request Page A of _ _,
SECTION 3 Summary of Analyses Methods and Results he dispersion analysis is based upon the rupture of a single 2.4x10' gal tank. The results of the dispersion analysis show that the maximum control room concentration is 354 ppm for stability category G, and 144 ppm for stability category F. Rese values exceed the toxicity limit of 100 ppm (TWA). The results also show that the maximum control room concentration is 59 ppm for stability category E. This is below the toxicity limit of 100 ppm (TWA). Therefore, only stability categories G and F will cause uninhabitable conditions in the control room, The probability of causing uninhabitable conditions in the control room due to an accidental release of naphtha is evaluated in accordance with NUREG-0800. Based on design input the occurrence probability of catastrophic rupture of atmospheric storage tanks is 6x104/ year. Also the occurrence probability of stability categories G and F is 0.205, and that of the NNE wind direction is 0.079.
These are the stability categories and the wind direction that would cause uninhabitable conditions in the control room.
Based on the above, the probability of causing uninhabitable conditions in the control room due to an accidental release of naphtha, P
, is determined as follows.
P
= Na, Pa ny, P,
- y.,, P,w %
where Nm, is the number of tanks, Pang, is the occurrence probability of tank rupture, Pomo,,, is the occurrence probability of the stability categories that would cause uninhabitable conditions in the control room, and P,w % is the occurrence probability of the wind directions that would cause uninhabitable conditions in the control room.
P. = (2) (6x104) (0.205) (0.079) = 1.95x10'7 The results show the probabilities of event occurrence to be on the order of 104 and 10~' for Acetaldehyde and Naphtha, respectively, which are acceptable based on the criteria specified in NUREG-0800, Standard Review Plan, Section 2.2.3. Therefore, no monitoring for these chemicals is required.
NC9006. Revision 6 - Offsite Analysis An independent verification / validation of the subject analyses contracted to PLG, Inc identified assumptions in Revision 5 that were overly conservative. This prompted further evaluation of the previous analyses which resulted in Revision 6 to the Onsite and Offsite Toxic Gas Analyses, NC9015 and NC9006, respectively. Revision 6 presents results based on a more realistic set of assumptions, which are consistent with the requirements set forth in Regulatory Guide 1.78 and NUREG-0570.
l OPGP05-ZN-0004 Rev.1 Changes to Licensing Basis Documents and Amendments to the Operating License CN-1979 Licensing Document Change Request Page11.of SECTION 3 Summary of Analyses Methods and Results NUREG-0570 suggests the use of a minimum spill thickness of I cm. Such an assumption is valid for spills on land. The spills of concern for this analysis are located on the Colorado River at it's nearest point to the STPEGS control rooms. For spills on quiescent water, a minimum spill thickness of 0.25 cm has been proposed. Revision 6 utilizes realistic pool spread ~models with a minimum spill thickness of 0.25 cm since the spills in the offsite analysis are on water rather than land. This assumption will yield pools having larger surface area and therefore a larger vapor release rate. This assumption is therefore more conservative than the assumption utilized in Revision 5.
- Ihe methodology / steps followed in Revision 6 to both.the Onsite Toxic Gas Analysis, NC9015, and Offsite Toxic Gas Analysis, NC9006 are described below.
Step 1: The establishment of the toxicity criteria.
Step 2: The debition of the source terms for the dispersion analysis are presented below in the chemical sperhic subsections.
Steps 3 through 5: Conduct dispersion analysis for a representative matrix of stabilities and wind speed conditions and validate the results.
Regulatory Guide 1.78 states that "the value of the atmospheric dilution factor between the release point and the control room that is used in the analysis should be that value that is exceeded only 5%
of the time". These high stability-low wind speed scenarios yield the highest concentrations of the hazardous substance at the control room air intake and meet the 5% exceedance criteria. If the concentration of the hazardous substance at the control room intake did not exceed the toxicity limit, no further analysis was conducted and it was concluded that no monitoring is required for that substance.
Steps 6 through 8: Prepare control room time histories to determine whether operators have adequate time to take protective action. The low dilution factor scenarios described above might not yield the fastest rise in concentration of the hazardous substance in the control room. Hence at this stage dispersion analysis was conducted for a representative matrix of stabilities and wind speed conditions. Control room time histories for the rise of concentration of the hazardous material were prepared. If the rise in the control room concentration of the hazardous material from the odor threshold to the toxicity limit occurred over a period greater than six minutes no further analysis was conducted.
Steps 9 and 10: Conduct release frequency analysis and PSA event sequence analysis to see if NUREG-0800 screening criteria cotild be met.
r
^
OPGP05-ZN.0004 Rev.1 Changes to Licensing Basis Documents and Amendments to the Operating License CN-1979 Licensing Document Change Request Page f1 of _,_
SECTION 3 Summary of Analyses Methods and Results ne following summarizes the source term determination and analysis conclusions for acetic acid and vinyl acetate.
He effect of releases of acetic acid and vinyl acetate, due to a barge accident, on the habitability of the STPEGS control rooms was studied using appropriate toxicity criteria (ERPG-2/IDLH) and dispersion models (dense gas in the near field). Immediately dangerous to life or health (IDLH) concentrations represent the maximum concentration from which in the event of respirator failure, one could escape within 30 minutes without a respirator and without any escape-impairing or irreversible health effects. ERPG-2 is the maximum airborne concentration below which nearly all individuals could be exposed for up to I hour without experiencing or developing irreversible or other serious health effects or symptoms that could impair an individual's ability to take protective action.
Since both acetic acid and vinyl acetate are substantially heavier than air, simple Gaussian models do not apply as pointed out in NUREG-0570, Section 2.2 "this diffusion model is applicable only to the vapors whose densities do not differ greatly from that of air". CHEM-MIDAS, a PLG computer code was used to conduct the dispersion analysis for these cases. CHEM-MIDAS is capable of dense gas dispersion analysis and of switching to Gaussian models at the point where the vapor cloud becomes neutrally buoyant. (Gaussian models were used in Rev. 5).
For the purpose of this analysis the code ALOHA has been used to verify the models implemented in CHEM-MIDAS. ALOHA is a dense gas dispersion code distributed by the U. S. Environmental i
Protection Agency (EPA), the National Oceanic and Atmospheric Administration (NOAA), and the National Safety Council (NSC). Due to limitations of spill size and duration that ALOHA can treat, it could not be used to directly analyze the dispersion for the scenarios of interest to this study.
Herefore, a benchmark case was analyzed using both CHEM-MIDAS and ALOHA. For both acetic acid and vinyl acetate it was concluded that CHEM-MIDAS yicids valid, but conservative results.
Acetic Acid Source Term:
He scenario that represents the maximum concentration accident for acetic acid is the instantaneous release of the entire contents of the largest container shipped by barge. The largest container holds 4.5 x 105 gallons of acetic acid. He ambient temperature and the temperature of the contents is assumed to be 100'F, which is the one percentile ambient temperature as per Revision 5. This analysis used a minimum spill thickness of 0.25 cm which represents an extremely consen'ative assumption. Further factors that will cause the actual vapor release to be smaller than the modeled quantities are listed on the following page..
OPGP05-ZN-0004 Rev.1 Changes to Licensing Basis Documents and Amendments to the Operating License CN-1979 Licensing Document Change Request Page d. of,_,,_
SECTION 3 Summary of Analyses Methods and Results s-Acetic acid is miscible in water.
Acetic acid is slightly heavier than water.
Instantaneous release of the entire contents of a container is physically not possible.
ne spilled material will be limited in area by the width of the Colorado River and will flow away from the STP site toward the Gulf of Mexico.
Results of Dispersion Analysis:
'lte source term resulted in concentrations that exceeded the 1000 ppm limit out to about 1.75 Km (1.1 miles). No further analysis is necessary since the IDLH value of 1000 ppm is not exceeded at the control room intake which is at a distance of greater than 2.8 miles from the river. Herefore, it is not required to monitor the control room. intake for acetic acid.
Vinyl Acetate Source Term:
The scenario that represents the maximum concentration accident for vinyl acetate is the instantaneous release of the entire contents of the largest container shipped by barge. The largest container holds 5
5.04 x 10 gallons of vinyl acetate. The ambient temperature and the temperature of the contents is assumed to be 100*F, which is the one percentile ambient temperature as per Revision 5. This analysis used a minimum spill thickness of 0.25 cm which represents an extremely conservative assumption. Further factors that will cause the actual vapor release to be smaller than the modeled quantities are listed below.
Instantaneous release of the entire contents of a container is physically not possible.
ne spilled material will be limited in area by the width of the Colorado River and will flow away from the STP site toward the Gulf of Mexico.
Results of Dispersion Analysis:
~
Runs were made for a tank rupture release of 5.04x10 gallons of vinyl acetate for undiked ronditions. He ERPG-2 limit of 75 ppm was exceeded beyond the 2.84 mile distance from the barge to the control room intake. The worst case conditio.n was for an "F" stability and a wind speed of 2.5 m/see which would result in the vinyl acetate limit being exceeded out to about 40 km (25 miles). Further analysis was conducted to determine the control room time history.
4 OPGP05-ZN 0004 Rev.1 Changes to Licensing Basis Documents and Amendments to the Operating License CN 1979 Licensing Document Change Request Pagefj_of SECTION 3 Summary of Analyses Methods and Results Joint frequency distributions were run to determine the percentage of the time a combination of wind speed, direction and stability were observed. 'Ihe analyses show the number of hours and the percent of all hours in the year that weather conditions would have caused control room intake concentrations" to exceed 75 ppm. For the barge accident scenarios, wind from the north, clockwise to the south-southeast were considered. The analyses show the peak concentration for each combination of direction, wind speed and stability that exceeded the 75 ppm limit for vinyl acetate.
Control room time histories generated from a CHEM-MIDAS run for Stability F and wind speed of 2.5 m/s were determined. For this case it takes more than 29 minutes from odor detection for the control room concentration to reach the ERPG-2 level with maximum air intake. If the dampers are closed after six minutes the control room concentration reaches only 22 ppm in 30 minutes. This is well within the six minute criterion for operators at STPEGS to take protective actions.
The maximum concentration of vinyl acetate for all of these runs is 910 ppm. A theoretical bounding calculation was conducted. The basis of this calculation is that the vinyl acetate concentration at the control room intake goes from zero to the maximum (910 ppm) in one computational time step of CHEM-MIDAS. It is thus impossible to get a faster rate of increase in the control room concentration of vinyl acetate irrespective of the prevailing meteorological conditions. For this case it takes 8 minutes for the control room concentration to rise to the ERPG-2 value with maximum air exchange rate. If the dampers are closed in six minutes, it takes 22 minutes for the control room concentration to rise to the ERPG-2 value. If the control room is in "recirc" mode from the beginning it takes 44 minutes for the control room concentration to reach the ERPG-2 level.
It was found that under the " worst" case conditions the concentration of vinyl acetate at the control room air intake does exceed the toxicity criterion used in this study. However, the time that it takes for the control room concentration to rise from the odor threshold to the toxicity limit is at least 22 minutes. Based on this result it was concluded that it is not necessary to monitor the control room air intake for vinyl acetate, since the vinyl acetate can be readily detected by odor within the first minute after arrival at the control room.
Conservatism inherent in the nnalysis:
It is not physically possible to have an instantaneous spill of 450,000 or 504,000 gallon of material. Even in a severe accident, the entire contents of the barge may not be released.
The size of the spill will be contained by the river banks. In this analysis such a constraint has not been applied. It has been postulated that the minimum thickness of the spill is 0.25 cm, which would be conservative even if the material could spill without any constraints.
OPGP05-ZN-0004 Rev.1 Changes to Licensing Basis Documents and Amendments to the Operating License CN-1979 Licensing Document Change Request Page ff( of _,,
SECTION 3 Summary of_ Analyses Methods and Results The river will be continuously removing the hazardous material. This effect has not been modeled.
The temperature of the river has been taken to be 100'F, which is high. The actual source term is likely to be lower.
In the case of acetic acid, the source term is likely to be substantially smaller since acetic acid will dissolve in water and will thus be removed from the surface.
The vapor cloud moves towards the STPEGS control room at approximately the wind speed.
The control room should be aware of the presence of the hazardous material well before it arrives at the control room air intake, since both materials have distinct odors and have also low odor thresholds. The odors would not go unnoticed by outdoor personnel. Further, STPEGS has an agreement with Hoechst Celanese and Lyondell Petrochemical for prompt notification in the event of a~ release.
For vinyl acetate the results represent a theoretical upper bound on the rate of increase of the control room concentration based on the maximum control room air intake concentration being reached in one computational time step of five minutes _. In reality CHEM-MIDAS runs show that it takes over two hours for the concentration to reach this peak value at the control room Intake.
For the calculations of control room time histories it has been assumed that even in "recirc" mode one of the three dampers remains open.
He use of ERPG-2 as the toxicity limit implies that it is possible to tolerate up to sixty minutes of exposure at those levels.
NC9015. Revision 6 - Onsite Analysis.
Revision 5 to the Onsite Analysis, NC9015, concluded that no monitoring of the control room air intake was necessary for any onsite chemicals. This analysis assumed modifications to the containment areas for ethanolamine and hydrazine. Further evaluation was conducted by PLG, Inc.
based on the above described methodology to verify the conclusions of Revision 5 based on a more realistic set of assumptions which are consistent with the requirements set forth in Regulatory Guide 1.78 and NUREG-0570.
~
%e following summarizes the source term determination.and analysis conclusions for ethanolamine (ETA) and hydrazine.
e-n m OPGP05 ZN-0004 Rev.1 Chnnge= to Licensin Basis Documents and Amendments to the Operating License CN-1979 Licensing Document Change Request Page _
of _
SECTION 3 Ermmary of Analyses Methods and Results Ethanolamine Source Term:
The temperature of the content.s and the ambient temperature is assumed to be 100#F. Minimum spill thickness is I cm as recommended by NUREG-0570 for spills on land. The onsite storage of ethanolamine has been identified in Cale No. NC9015, Rev. 5 as shown below.
Location /1dentifier Concentration Capacity Containment Area Distance to CR 1 Air latake CR-2 AirIntake Ihhanolamine Tote 80% Aqueous 500 ca!!ons (one 2.86 m'
> 115:n
> t l5m Tanks (Temporarr of Two Tote i
14 cation Box Tanks)
- 3M)
Ethanolamine 80% Aqueour 500 callons (One 35 m'
> 115rn
> 115m Tanks (Area 18) of Five Tanks)
Aqua Ammonia 85% Aqueous 13,400 callons 80 m'
> 115m
> ll5m Taak Results of Dispersion Analysis Two Chem-MIDAS runs were made using the 0.5% meteorology: for source terms Nos. 2 and 3 in the table above. Source term No.1 is bounded by source term No. 2 because of its smaller containment area. The peak concentrations at 100m were 2.9 ppm and 5.4 ppm for source term Nos.
2 and 3, respectively. In both cases the 1,000-ppm limit was not exceeded. The actual distance from the source to the control room air intake is greater than 115m. Based on these results no further analysis was conducted and it was concluded that it is not required to monitor the control room air intake for ethanolamine.
Hydrazine Source Term The temperature of the contents and the ambient temperature is assumed to be 100*F. The table given on the following page identifies the onsite locations for hydrazine storage. The minimum spill thickness was taken to be 1 cm as recommended by NUREG-0570. Containment does exist around the 120-gallon tank; however, the area of the berm is so large that it is possible to reach the minimum spill thickness of 1 cm. All the scenarios in the table following are therefore bounded by the release of the entire contents of the 120-gallon tank.
OPGP05-ZN-0004 Rev.1 Changes to Licensing Basis Documents and Amendments to the Operating License
~
CN-1979 Licensing Document Change Request Page ff_ of ___
SECTION 3 Summary of Analyses Methods and Results ir-""""
Il location / Identifier Concentration Capacity Contalsment Area Distance and Direction to CR-1 AirIntake CR-2 AirIntake 8
in TGB-1 35% Aqueous 500 Gallon 21.9 m 91 m NW 92m NE in TGB-1 10% Aqueous 500 Ca!!ons 21.9 m' 91m NW 92m NE in TGB-2 35% Aqueous 500 Ga!!ans 21.9 m8 252m WNW 92m NW in 10B-2 10% Aqueous 500 Ga!!ons 21.9 m' 252m WNW 92m NW South of TGD-1 35% Aqueous 500 Galices 2.87m8 138m %NW 72m NE South of TGB 2 35% Aqueous 500 Gahne LR7m8 317m W 138rn WNW Auxiliary Boller 35% Aqueous 120 Gallons No Containment 99m SSW 172m SE Hydrazine Tank Building 19 35% Aqueous 55 Gallons (7 no.)
No Containment 340m 340m Section G Results of Dispersion Analysis Chem-MIDAS runs showed that the toxicity limit of 80 ppm is not exceeded beyond 50m from the source of the spill. The shortest distance from a hydrazine tank to the intake of either control room is 72m. Therefore the toxicity limit will not be exceeded at the control room air intake for any of the above scenarios. Based on these results no further analysis was conducted and it was concluded that it is not required to monitor the control room air intake for hydrazine.
- Ihe effect of releases of ethanolamine and hydrazine, due to failure of onsite storage tanks, on the habitability of the STPEGS control rooms was studied using appropdate toxicity criteria (IDLH) and dispersion models (dense gas in the near field).
It was found that under the " worst" case conditions the concentration of either ethanolamine or hydrazine at the control room air intake does not exceed the toxicity criterion used in this study.
Revision 6 to the Onsite Toxic Gas Analysis NC9015 conclides it is not required to monitor the
~
control room air intake at STPEGS for Ethanolamine (ETA) or Hydrazine to assure control room habitability on the requirements set forth in Regulatory Guide 1.78.
Conservatism Inherent in the Analysis:
Entire contents of the storage tank are assumed to be instantaneously released.
The ambient, ground and spill temperature has been taken to be 100'F, which is the one percentile temperature.
'Ihe use of IDLII as the toxicity limit implies that it is possible to tolerate up to thirty minutes of exposure at those levels.
OPGP05-ZN-0004 Rev.1 Changes to Licensing Basis Documents and Amendments to the Operating License CN-1979 Licensing Document Change Request Page jf{, of _
SECTION 3 Summary of Angl.tses Methods and Realts General Conclusions /Results:
Based on the previous analysis STPEGS design features incorporated instrumentation to detect, alarm, and provide automatic isolation of the control room as necessary for Vinyl Acetate and Anhydrous Ammonia. Instrumentation is also provided to detect and alarm as necessary for hydrochloric acid, acetic acid, acetaldehyde, and naphtha.
Revisions 5 & 6 to these analyses justify elimination of these instrument functions. Botn revisions 5
& 6 of the analyses comply with Regulatory Guide 1.78, NUREG-0570, and NUREG-0800, Standard Review Plan, Section 2.2.3.
The Revision 6 analyses identified assumptions in Revision 5 that were overly conservative and presented resuits based on a more realistic set of assumptions.
The Toxic Gas monitoring requirements detailed in the UFSAR and TRM are no longer valid. The subject CN is issued to correct the references in the UFSAR and remove the monitoring requirements from the TRM.
OPGP05-ZN-0004 Rev.1 Changes to Licensing Basis Documents and Amendments to the Operating License CN-1979 Licensing Document Change Request Page A of __
SECTION 4 Sununary ofDesien Channe to Disable the Analyzers
' Design Change Package DCP# 94-361510 disables the Toxic Gas Analyzers, associated actuation circuitry, ERFDADS displays and annunciators. His design change is issued to disable the analyzers based on the results of Revisions 5 & 6 to the Onsite and Offsite Toxic Gas Analyses, NC9015 and NC9006, respectively.
- Ihis design change packege is intended to disable the analyzers by making changes to the key drawing associated with the Toxic Gas Monitoring System. He design change consists of lifting leads and installing jumpers to disable toxic gas monitoring inputs to the Control Room HVAC actuation circuitry, ERFDADS computer points and associated control room annunciators. EE580 cards are provided to replace the normally closed contacts of the toxic gas system with a jumper in series between the smoke detectors contacts and the coils of the actuation relays. Installation of this jumper will eliminate the toxic gas analyzer contacts from the actuation circuit. Leads will also be lifted to the ERFDADS computer points, which in conjunction with ERFDADS software changes will disable the ERFDADS displays and control room annunciators. Power to the analyzers will be removed by lifting leads at each analyzers associated distribution panel. Implementation of this design change will isolate the Toxic Gas Monitoring System from the HVAC system, therefore preventing any future interaction or risk of spurious actuations.
Following a detailed cost analysis, a decision will be made to either abandon the system in place or remove all or part of the chemical detection system. At that time an all encompassing design change package will be issued to incorporate these changes to all vendor and design documents which are associated with the Toxic Gas Monitoring system.
j OPGP05-ZN-0004 Rev.1 Changes to Licensing Basis Documents and Amendments to the Operating License CN-1979 Licensing Document Change Request Page i l of _
SECTION 6 i
UFSAR Sections 2.2.3. 6.4. 7A & 9.4 The following pages include the UFSAR sections which reference the Toxic Gas Moni. tors. Changes made by this Licensing Document Change Request are marked on the affected page. Affected pages are noted as
" requiring revision" in the lower margin.
o
l OPGP05-ZN-0004.
Rev.1 Changes to Licensing Basis Documents and Amendments to the Operating License CN-1979 Licensing Document Change Request Page 26 of UFSAR SECTION 2.2 i
Nearby Industrial. Transportation, and Military Facilities..
Affected Sections:
2.2.3 Evaluadon Of Potential Accidents i
2.2.3.1 Determimig of Design Basis Events 2.2.3.1.1.
Industrial Facilities 2.2.3.1.2 Transportation 2.2.3.1.6 Plant Site Chemical Storage Protection 2.2.3.2 Effects of Design Basis Events Table 2.2-5 Potentially Hazardous Chemicals Stored at Celanese Chemical Company and on the STPEGS Site Tnble 2.2-6 Potentially Hazardous Chemicals Shipped from the Celanese Chemical Company.
... _ _