ML18096A555
| ML18096A555 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 02/28/1992 |
| From: | Labruna S Public Service Enterprise Group |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-3.D.3.4, TASK-TM NLR-N92016, NUDOCS 9203100109 | |
| Download: ML18096A555 (5) | |
Text
Public Service Electric and Gas Company Stanley LaBruna Public Service Electric and Gas Company P.O. Box 236, Hancocks Bridge, NJ 08038 609-339-1200 Vice President - Nuclear Operations FEB 2 8 1992 NLR-N92016 United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 Gentlemen:
SAFETY EVALUATION OF A POSTULATED ACCIDENT OF AN AMMONIUM HYDROXIDE STORAGE TANK ON CONTROL ROOM HABITABILITY SALEM UNITS 1 AND 2 DOCKET NOS. 50-272, 50-311 Public Service Electric and Gas (PSE&G) has completed the safety evaluation of the onsite storage of ammonium hydroxide and the impact of a postulated storage accident on control room habitability.
Compensatory actions implemented from previous analysis, as discussed in our letter dated December 30, 1991, as well as tanker truck delivery accidents are addressed in. the safety evaluation.
The safety evaluation concludes that there is no impact on control room habitability from a postulated ammonium hydroxide storage tank or tanker truck accident using the changes described in our December 30, 1991 letter.
The evaluation shows the acceptability of using concentrations of 27.5 wt.% or 15 wt.%
at specified volumes in accordance with a temperature versus volume curve.
The basis for the safety evaluation's conclusion is that ammonium hydroxide's volatility (liquid) is concentration ahd temperature dependent and its impact on habitability is proportional to the quantity of ammonia (gas) available for release and dispersion to the control room intakes.
A determination was made of the quantities of ammonium hydroxide that can be stored for 27.5 wt.%
and 15 wt.% at various temperatures.
A calculation of the concentration of ammonia gas accumulating in the control room, as a result of a postulated storage tank failure, concludes that the regulatory criteria are met if the compensatory measures specified by the safety evaluation are foll~wed.
The calculation performed in support of the safety evaluation used the VAPOR model, which is based on the equations of NUREG 0570.
VAPOR uses a single puff release which is
,~2o310AOD*~-b;g~~~72 PDR PDR I
p
Document Control Desk NLR-N92016 2
FEB 2 8. 1992 instantaneously vaporized into the atmosphere.
It also models atmospheric and solar heat fluxes, consistent with the assumption of outdoor storage tanks (vs. Salem's indoor tank).
These heat fluxes increase the overall heat transfer to the release, thereby increasing the accumulation of the vapor in the control room.
The CHARM model, which was used for PSE&G's preliminary assessment in September 1991, indicated that the toxic limit would not be exceeded for the as found condition of the tanks (i.e., prior to any compensatory measures).
CHARM, which has been used by the EPA for industrial applications, models the release as a function of time (sequential puffs vs. single puff release).
CHARM also allows the omission of the atmospheric and solar heat fluxes because of the indoor location of the Salem tank.
Therefore, the differences in mass and heat transfer mechanisms between the two models result in significant differences in the calculated results.
Because the VAPOR model is considered more conservative, PSE&G has used it in support of the safety evaluation.
The potential adverse impact of a postulated storage tank failure on control room habitability, prior to performance of the safety evaluation and implementation of compensatory measures, was reported via LER 50-272/91-038, January 16, 1992.
In accordance with the request in Inspection Report 50-272/91-32 and 50-311/91-33, the following is the reason that ammonium hydroxide was not considered previously in support of initial licensing, or in response to NUREG-0737, TMI Action Item III. D. 3 *. 4, for its impact on control room habitability.
As discussed in LER 50-272/91-038-00, the apparent cause of this condition was determined to be inadequate design review.
The Salem FSAR was written to the June 30, 1966 AEC Guide for the Organization and Contents of Safety Analysis Reports and AEC General Design Criteria dated July 10, 1967.
The AEC criteria did not require review and evaluation of site hazards to the degree required after Salem was licensed.
The FSAR was submitted in 1972 and a SER issued October 11, 1974.
FSAR Section 10.2.1.6, Chemical Feed System, only identified morpholine as the chemical to be used for pH control.
Morpholine is less toxic than ammonia and has a higher boiling point.
The FSAR made no commitment to Regulatory Guide 1.78 (June 1974),
but did evaluate the potential effects of hazardous materials stored onsite, in response to FSAR Review Question 2.11 (September 1972).
After submittal of the FSAR, but prior to issuance of an operating license, Section 10.2.1.6 was revised by Amendment 37 (April 1976) to change secondary water treatment from morpholine to ammonium hydroxide.
Document Control Desk NLR-N92016 3
FEB 2 8 1992 During licensing of Salem Unit 2, an assessment of the ability to meet or comply with Regulatory Guide 1.78 was conducted, as summarized in PSE&G internal memorandum dated September 14, 1977.
The engineering assessment noted that Table C.1 of Regulatory Guide 1.78 did not contain ammonium hydroxide, although it did contain ammonia.
The memo stated that ammonium hydroxide was stored in sufficient quantities to pose a potential problem.
However, it was concluded that "there should be little problem in maintaining a habitable environment in the Salem Unit 2 control room following a postulated hazardous chemical release".
The assessment's conclusions were based on the ability of the control room ventilation design to meet 10CFR50 Appendix A, Design Criteria 19 regarding habitability for a LOCA.
It was assumed that the effects from a LOCA were more limiting than the effects from a ammonium hydroxide release.
In response to NUREG-0737 Action Item III.D.3.4, PSE&G notified the staff by letters dated August 13, 1980 and July 1, 1980 that it had reviewed the criteria of the Standard Review Plan (SRP) and Regulatory Guide 1.78, and concluded the Unit 2 control room was protected from unacceptable levels of hazardous chemicals on or in the vicinity of the site.
PSE&G's July 1, 1980 response to Action Item III.D.3.4 references the response to FSAR Question 9.60, regarding toxic chemicals transported past the site, using the guidance of Regulatory Guide 1.78.
The response provided a table of hazardous chemicals stored onsite which were identified in Regulatory Guide 1.78, Table C-1.
It is assumed the response did not identify ammonium hydroxide because it was not in the regulatory guide table.
PSE&G's response to Salem FSAR Question 9.60 included sodium hydroxide, which is one of two chemicals identified in response to the inspection report.
PSE&G's response to FSAR Question 9.60 concluded that sodium hydroxide was not volatile and therefore no airborne hazard existed.
PSE&G's letter dated December 30, 1991, which identifies sodium hydroxide and hydrazine, also concludes that these chemicals have a low volatility and would not be expected to be an airborne hazard for control room habitability.
Review of the FSAR shows that hydrazine was an original feed chemical for secondary water chemistry control.
Hydrazine is not listed in Regulatory Guide 1.78.
Therefore, it is assumed that the original review concluded a low volatility liquid, not listed as a hazard, did not have to be identified.
In response to a request by NRC Inspector R. Nimitz per telephone conversation on February 7, 1992, the following is the basis by which Hope Creek did not consider ammonium hydroxide at Salem and evaluate its impact on control room habitability:
Document Control Desk NLR-N92016 4
FEB 2 8 1992 The determination of Hope Creek's Design Basis Events (DBE) evaluated the possibility of an impact associated with the hazards from the Salem site by toxic vapor dispersion as discussed in Hope Creek UFSAR Section 2.2.3.1.
Potential accidents involving release of toxic chemicals are evaluated in Hope Creek UFSAR Section 2.2.3.1.3 and list chemicals stored at Salem in Table 2.2-4.
Hope Creek's assessment is based on the data contained in Salem's UFSAR.
Since Salem did not specifically identify ammonium hydroxide as a toxic chemical stored within the plant, Hope Creek did not evaluate its impact.
The UFSAR evaluations of toxic chemicals at Salem concludes there are no impacts on control room habitability. Therefore, it was concluded that Salem's toxic chemicals would not impact Hope Creek's control room habitability.
As a result of additional chemicals being identified at Salem, Hope Creek's UFSAR will also be revised.
Hope Creek's UFSAR will have a change notice processed and approved by July 1992.
A. safety evaluation of the impact from the Salem ammonium hydroxide storage tank and tanker delivery truck accident on Hope Creek is scheduled to be completed by the end of April 1992.
An evaluation of the impact on Hope Creek from the two other chemicals at Salem (i.e., sodium hydroxide, hydrazine) will be completed by the end of July 1992.
In summary, Salem's original design was not based on Regulatory Guide 1.78 or the criteria of standard Review Plan Sections 2.2 and 6.4.
However, in response to later NRC requests, the plant design was evaluated for compliance with the intent of the regulatory guide and NRC criteria.
Based on an error in design review, PSE&G concluded that Salem's design met the intent of those criteria.
Upon discovering that the ammonium hydroxide storage tank posed a potential control room habitability hazard, PSE&G reported the condition, took compensatory actions, and completed a safety evaluation to ensure that control room habitability would not be compromised in the event of a tank rupture accident.
Should you have any questions, please contact us.
_Sincerely,
Document Control Desk NLR-N92016 5
C Mr. T. T. Martin, Administrator - Region I
- u. s. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Mr. J. c. Stone, Licensing Project Manager -
Salem U. S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Rockville, MD 20852 Mr. T. P. Johnson (S09)
USNRC Senior Resident Inspector Mr. K. Tosch, Chief NJ Department of Environmental Protection Division of Environmental Quality Bureau of Nuclear Engineering CN 415 Trenton, NJ 08625 FEB 2 ~ 1992