ML15070A086
| ML15070A086 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 03/04/2015 |
| From: | Office of Information Services |
| To: | |
| References | |
| FOIA/PA-2015-0076 | |
| Download: ML15070A086 (7) | |
Text
FOIA/PA NO: 2015-0076 GROUP: B RECORDS BEING RELEASED IN-PART The following types of information are being withheld:
Ex. 1:E3 Records properly classified pursuant to Executive Order 13526 Ex. 2:[D Records regarding personnel rules and/or human capital administration Ex. 3:0 Information about the design, manufacture, or utilization of nuclear weapons ElInformation about the protection or security of reactors and nuclear materials E"Contractor proposals not incorporated into a final contract with the NRC "Other Ex. 4:- Proprietary information provided by a submitter to the NRC "Other Ex. 5 :7 Draft documents or other pre-decisional deliberative documents (D.P. Privilege)
M Records prepared by counsel in anticipation of litigation (A.W.P. Privilege)
M-Privileged communications between counsel and a client (A.C. Privilege)
E-Other Ex. 6:E] Agency employee PII, including SSN, contact information, birthdates, etc.
[-Third party PII, including names, phone numbers, or other personal information Ex. 7(A):E] Copies of ongoing investigation case files, exhibits, notes, ROI's, etc.
'7*Records that reference or are related to a separate ongoing investigation(s)
Ex. 7(C): '-1 Special Agent or other law enforcement PII
-]PII of third parties referenced in records compiled for law enforcement purposes Ex. 7(D): M-Witnesses' and Allegers' PH1 in law enforcement records E--]Confidential Informant or law enforcement information provided by other entity Ex. 7(E): [--Law Enforcement Technique/Procedure used for criminal investigations
.*T*cjnique or procedure used for security or prevention of criminal activity Ex. 7(F):)Information that could aid a terrorist or compromise security
S aMeTy* -RECURITwan RConfTEr ImFoRA ATis Safety Review and Confirmatory Analysis Entergy's 10 CFR 50.59 Safety Evaluation Algonquin Incremental Market (AIM) Project Indian Point Energy Center (IPEC)
Introduction Algonquin Gas Transmission, LLC (Algonquin) proposes an installation of new 42-inch diameter pipeline near the southern boundary of IPEC for the transport of natural gas as part of the AIM Project, to replace the existing 26-inch pipeline in vicinity of IPEC, which will remain in place but idled. Entergy prepared a 10 CFR 50.59 Safety Evaluation (Reference 1) related to the proposed AIM Project with an enclosure OHazards Analysis" (Reference 2). The 10 CFR 50.59 safety evaluation and enclosure covered the consequences of a postulated fire and explosion following release of natural gas from the proposed new (southern route) AIM Project 42-inch pipeline south of IPEC and determined exposure rates associated with failure of that proposed 42-inch natural gas pipeline. Based on the hazards analysis and also accounting for the pipeline design and installation enhancements, Entergy has concluded that the proposed AIM Project poses no increased risks to IPEC and there is no significant reduction in the margin of safety. Therefore, Entergy further concluded that the change in the design basis external hazards analysis associated with the proposed AIM Project does not require prior NRC approval.
The NRO/DSEA/RPAC Staff at NRC Headquarters has reviewed Entergy's hazards analysis that supports the 10 CFR 50.59 Safety Evaluation related to the AIM Project, by performing independent confirmatory calculations to determine whether or not the licensee's conclusion is reasonable and acceptable, and also to ascertain that there is adequate reasonable assurance of safe operation of the plant or safe shutdown of the plant.
Summary of Evaluation The staff has reviewed Entergy's "Hazard Analysis" supporting the 10 CFR 50.59 Safety Evaluation related to the AIM Project. Entergy evaluated potential hazards to safety-related structures, systems and components (SSCs). and also. SSCs. important to safety (SSC. ITS) using reasonable assumptions and rationale. Entergy's methodology is appropriate and acceptable. The staff has performed independent confirmatory calculations with conservative assumptions and rationale using RG 1.91. methodology and also using. the. ALOHA model for vapor plume explosion. The staff also calculated the frequency of potential pipe line failure and determined that there is no additional potential risk to the safe operation of the IPEC units.
Based on the review of the hazards analysis provided as part of Entergy's 10 CFR 50.59 Safety Evaluation, and the staff's independent confirmatory calculation results using conservative VITI assumptions and rationale, the. staff concludes that (1) no 1. psi overpressure is extended to. any safety-related SSG inside the Security Owner Control Area (SOCA),IZ]F)
However, nearby SSG ITS would be affected, because the calculated minimum safe distances to the impacts are exceeded. The staff finds that the impacts to the SSC ITS from the proposed new 42-inch pipeline, are bounded by the impacts from low probability. events of extreme natural phenomena (including seismic activity, tornado winds, and hurricanes) which have been assessed and already addressed in the Indian Point Units 2 and 3 UFSARs. The cloud flash fire may occur aloft and bum very rapidly In a few seconds, without affecting any safety-related SSCs or equipment; and the existing margin of safety is not expected to be reduced due to a potential rupture of the proposed AIM Project pipeline near IPEC. The staff also finds that the applicant's conclusions, that the potential rupture of the proposed AIM Project pipeline near IPEC poses no threat to safe operation of the plant or safe shutdown of the plant, are reasonable and acceptable, and also comparable to the staff's conclusions.
Technical Evaluation.
The staffs independent confirmatory analysis was performed based on the rupture of the proposed new 42-inch natural gas pipeline consisting of about 3 miles between isolation valves, of which the enhanced section of pipeline length is identified to be 3935 ft., located along the southern route near IPEC. The. analysis assumed that rupture of the natural gas pipeline may result in an unconfined explosion or jet flame at the source, delayed vapor cloud fire, or vapor cloud explosion. Missile generation may also accompany the rupture/explosion. For the assessment of an unconfined explosion, RG 1.91 (Reference 3) methodology was used to calculate the minimum safe distance. For the jet flame, cloud fire, and vapor cloud explosion, the ALOHA chemical. release modeling. computer code (Reference. 4) is. used. to. determine. the hazard.
impact distances which are compared with the actual distances at IPEC to structures, systems and components (SSCs) related to safety or SSCs important to safety (SSC ITS), as listed in Reference 2,. Table 1, in order to assess the impact potential.. ALOHA is. run. using the appropriate source term (amount.of methane released) for the scenario considered, using (b()Fconservative meteorolo-gical conditionsJ(77 (F)
Open country ground roughness conditions modeling assumptions were chosen.
EXPLOSION The ALOHA model for explosion scenario 1 conservatively assumed that the pipe rupture occurred at the. far end of the pipe line above the surface, considering the length of pipeline to be 3 miles, )=
lat a maximum operating pressure ot 850 psig. The ALOHA calculation tor this scenario resulted in a maximum sustained methane release rate of b
)
and estimated total release amount of I considering manual closure of the isolation valves within 3 minutes. Conservatively assuming the maximum release Fb)7F)
J(Wi)(F) t and determining the TNT equivalent amount with al(jb)F)
(t-n(Fl lwith equationogiven below, the minimum safe distance (d) to 1 psi overpressure is calculated to b4bMjF) 'by using RG 1.91 methodology as follows:
WTNT= (Mf
- DHC
- Y)/4500 where WTNT= TNT equivalent Mass, kg Mf = Mass of vapor,, kg.
DHC = Heat of combustion, kj/kg (50030) y =4(b)(7)(F)I d=. 45 *I (w)"3 where.
d=. minimum safe distance (ft) to I psi overpressure w=. TNT equivalent mass in pounds This calculated minimum safe distance of.
is smaller than. the actual distance of Irm-1to the SOCA (Security Owner Control Area) from the pipeline at the far end. above surface. orll)"" I
,-).to.
the nearest safety-related SSC (nearest safety-related SSC inside SOCA from is about Lin from. the edge of the SOCA) and therefore. 1. psi overpressure. is not expected at any safety-related SSC inside the SOCA from a potential rupture and explosion. at the. far end of the.
pipeline located above the surface. However, as the. calculated. minimum safe. distance of E (bXT-).___
is larger than. the. actual. distances to all. SSC ITS,. they may experience greater than. 1. psi overpressure.. Therefore, the SSC ITS would. be. impacted.. Nevertheless, their impacts are bounded by the severelbeyond design. basis accidents considered as part of low probability.
events. such as natural. phenomena that include. seismic, hurricane. and tornado events including-Loss of Offsite Power and Station. Black Out (SBO). considerations with design. of redundant.
systems, engineering safeguards and. mitigation measures. in the. plant UFSARs. The frequency of exposure due. to. failure of these SSC ITS. from potential rupture. of AIM Project is also. briefly.
presented later in. this, report to. address. whether the margin. of safety. is. reduced. or compromised due. to. rupture. of AIM Project.
Assuming. a)'Xf)
Ifor an. unconfined methane explosion (as given in RG 1.91), the.
methane amount determined from. the. maximum Ib)7(F)
I of methane releasedF" 771 d(b)0).. Idetermined from the. ALOHA run) is used as an instantaneous methane release to simulate the. vapor cloud dispersion, transport, and delayed explosion I(bX1)(f)
(b)(7)(F) fMoreover, the SSCs are generallv designed to withstand. an overpressure of 3 Dsi.. (b)((F)
I I(b)VXF) las methane is buoyant and quickly rises aloft, disperses rather rapidlyi l(b)(7)(F)
Therefore, the ALOHA model was rerun with the same input except with an assumption. of no.
congestion In the area.. The ALOHA model resulted In no vapor cloud. explosion of 1. psi.
SENSITIVE
-E~ SLCUR I EDLLIT IFJFORMAI
-4.-
overpressure. at any distance, due. to potential. ignition. The potential. pipe. rupture. underground. at the enhanced section of the pipeline would. be expected to. result in a slower methane, release.
rate, and. thereby. have. potentially much. lower, impacts than those determined as above.
JET. FIRE The ALOHA model. was run conservatively assuming that the, pipe. rupture occurred at the, far end. of the pipe line above. the surface, considering. the. length. of pipeline to. be. 3. mlles,I:'
1(bXTXF)
I at a maximum operating pressure of 850 psig... Methane. is assumed. to be released from the ruptured. pipe as a flammable gas and burning. The. ALOHA model run resulted In a maximum bum rate o t(b)M(F) and an. estimated total. amount burned offmm I-and considering manual closure. of the isolation valves within 3 minutes... The, distances (Table. 2) to thermal radiation levels of.
5.0 kW/m2,. and 2.0 kW/m2 calculated, by ALOHA are FF' (bTF)
Jrespectively..
The ALOHA model. was also run. conservatively assuming. that the. rupture. of pipe occurred in the middle of the. pipe located. underground. at the enhanced section identified. close. to the SOCA, considering half the. length. of the. pipeline. between. isolation valves. (1.5. miles) on each.
side. of the rupture. location, I
V rat a maximum operating pressure of 850. psig... Methane is assumed. to. be. released. from e ruptured. pipe. segment as. a burning. flammable. gas. The. ALOHA model. run. resulted. in. a maximum bum rate of
=
I and considering closure of the isolation valves within 3 minutes... The calculated,distances(Table 2) to the thermal radiation levels of.
5.0 kW/m2, 2.0 kW/m2 arerMI-7 respectively.
The distances determined. to the thermal radiation level. of (b)7) )
which has a potential to damage structures and equipment) due to potential pipe rupture at far end of the pipeline or in middle, of the. pipeline. arel(b)(7)(F) respectively... Both of these determined. distances.
are. smaller than the actual. distances.
o and 1580 ft, respectively, to. the SOCA, and.
therefore, jet fire. would. not pose. any adverse. effect on. SSCs. related to. safety... However, it may impact some, of the SSC ITS. as the. radiation. level. of (b)()(F)
-Jmay be exceeded. for some.
SSC. ITS. outside of the. SOCA.. Nevertheless,. the impacts to SSC. ITS. are. bounded by the.
severe/beyond design. basis. accidents. considered as part of seismic. and. tornado. events.
covering Station. Black Out (SBO) and Loss of. Offsite Power considerations, with. design of.
redundant. systems, engineering. safeguards. and. mitigation. measures. already addressed in. the plant UFSARs...
CLOUD. FIRE The. ALOHA model. was run conservatively assuming that the rupture. of pipe. occurred. at the. far end. of the pipe. line. above. the. surface, considering. the, length. of pipeline to. be. 3 miles,.IME
()at a maximum. operating. pressure CEl3It IE Ia-.
3ECUlR~vITY
- ,EllTEDP I
blrO.
lT V~lrJTI Nl.
of 850 si The. ALOHA model. run. resulted. in a maximum. sustained. release rate of.
- b)VXF)
- 1. and. an. estimated. total release. amount of7TF" (V
Jcnsidering manual. closure. of the isolation valves within 3 minutes... Conservatively assuming the. maximum release. rat l(W'-F)
I of methane. (determined.
from the. ALOHA run) is used as an instantaneous releasefb)Vn(F)
Jto simulate the vapor cloud dispersion,. transport to determine the. distance to. reach the. methane lower explosive limit (LEL). of 44,000 ppm. The ALOHA model determined a distance of IW7Zto reach the LEL. This estimated distance would bound the potential distance to the. LEL from the rupture in the. middle of pipe. in. the enhanced area buried underground... Even though the methane plume travels. for a long distance,. it is buoyant and rises aloft quickly and, therefore,.
also. bums rather rapidly in. seconds far above the ground without sustaining. and. without challenging the structures and. components, If enough oxygen. is available. Therefore,. the impact from cloud fire on SSCs and equipment is not considered challenged.
DETERMINATION OF EXPOSURE RATE FOR FAILURE OF THE AIM PROJECT PIPELINE NEAR IPEC Based on Pipeline Hazardous Materials Safety Administration (PHMSA) data (www.phmsa.dot.gov),. and also published information from "Handbook of Chemical Hazards Analysis. Procedures" (Reference 5),. the accident rate. of pipes greater than 20 inches diameter is about 5. x I 04/mile-yr... Assuming 3. miles of AIM. Project pipeline. near IPEC, the. accident rate is determined. to be 1.5. x 10"3/yr. Based on the information in these references, estimating 1.
percent of accidents. result in. a complete pipe. break or 100 percent instantaneous. release,. and assuming. also. only 5 percent of the time. that the released gas. becomes. ignited leading to.
potential. explosion, the explosion frequency for the AIM project pipeline. near IPEC is. calculated to. be about 7.5 x 10"7/yr. If this release is due to the underground. pipe,. the frequency. of explosion will. be further reduced. by at least an order of magnitude.. In addition, the frequency of a large radioactivity release from the reactor due to the frequency of the above pipe rupture event, considering. operating reactor conditional core damage frequency (CCDF), would be at least a few orders of magnitude lower, and. therefore would. not be. identified. as. a design basis event...
Therefore, it is concluded. that the pipe failure resulting in a methane release from the. proposed AIM Project near IPEC, would. not reduce any further the. existing safety margins, and. would not pose. a threat to. the. safe operation. of the. plant or safe. shutdown..
CONCLUSION......
Based on the review of the. hazards analysis. provided as part of Entergy's 10. CFR 50.59. Safety Evaluation. related. to the. AIM Project near IPEC,. and. staffs. independent confirmatory calculation results. using conservative assumptions. and rationale,. the staff concludes that no I psi overpressure. is extended. to. any safety-related SSC inside the SOCAI~h)(7)(F)
However, nearby SSC ITS would be affected, as the calculated minimum safe distances to the impacts are exceeded, but these impacts are bounded by the impacts from low probability events of extreme natural phenomena that include seismic, tornado winds, hurricanes which have been assessed and already addressed in UFSAR. Cloud flash fire may occur aloft and bum very rapidly in few seconds, without affecting any safety related SSCs or equipment, and the existing margin of safety is not expected to be reduced due to. potential rupture of the proposed. AIM Project pipeline near IPEC. The staff also finds that the applicant's conclusions that the potential rupture. of the proposed AIM Project pipeline. near IPEC. poses no threat to safe operation. of the. plant or safe. shutdown of the plant are reasonable and acceptable.. The.
staffs review finds that the hazards analysis supporting the licensee's 10 CFR 50.59 safety evaluation. isappropriate and shows that there is not more than a minimal increase to. the likelihood of occurrence or consequences of damage to a safety-related SSC or SSC ITS, when compared to the current hazards analysis in the plant UFSARs.
REFERENCES.
1..
Entergy, "10 CFR 50.59. Safety Evaluation and Supporting Analyses. Prepared in.
Response to. the..
Algonquin Incremental Market Natural. Gas Project Indian. Point Nuclear Generating.
Units Nos. 2 & 3," NL-14-106, August 21, 2014. ML14245A110.
- 2.
Entergy, "Hazards Analysis," Enclosure to NL-14-106, August 21, 2014.
ML14245A111. (Non-public)..
- 3.
US Nuclear Regulatory Commission, Regulatory Guide 1.91, "Evaluations of Explosions Postulated to Occur at nearby Facilities and on Transportation Routes Near Nuclear Power Plants,". Revision 2, April 2013..
4..
US EPA,. NOAA,"ALOHA User's. Manual,". February. 2007.
5...... FEMA, US. DOT,. US. EPA,. "Handbook of Chemical. Hazard. Analysis. Procedures."....
Principal Contributor. Rao Tammara Date: October 16, 2014 Q
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